arch/kmap: remove redundant arch specific kmaps

The kmap code for all the architectures is almost 100% identical.

Lift the common code to the core.  Use ARCH_HAS_KMAP_FLUSH_TLB to indicate
if an arch defines kmap_flush_tlb() and call if if needed.

This also has the benefit of changing kmap() on a number of architectures
to be an inline call rather than an actual function.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200507150004.1423069-4-ira.weiny@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/xtensa: move kmap build bug out of the way

Move the kmap() build bug to kmap_init() to facilitate patches to lift
kmap() to the core.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200507150004.1423069-3-ira.weiny@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/kmap: remove BUG_ON()

Patch series "Remove duplicated kmap code", v3.

The kmap infrastructure has been copied almost verbatim to every
architecture.  This series consolidates obvious duplicated code by
defining core functions which call into the architectures only when
needed.

Some of the k[un]map_atomic() implementations have some similarities but
the similarities were not sufficient to warrant further changes.

In addition we remove a duplicate implementation of kmap() in DRM.

This patch (of 15):

Replace the use of BUG_ON(in_interrupt()) in the kmap() and kunmap() in
favor of might_sleep().

Besides the benefits of might_sleep(), this normalizes the implementations
such that they can be made generic in subsequent patches.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian König <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Link: http://lkml.kernel.org/r/20200507150004.1423069-1-ira.weiny@intel.com
Link: http://lkml.kernel.org/r/20200507150004.1423069-2-ira.weiny@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmalloc: fix a typo in comment

There is a typo in comment, fix it.
"nother" -> "another"

Signed-off-by: Jeongtae Park <jtp.park@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20200604185239.20765-1-jtp.park@samsung.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/debug: add tests validating architecture page table helpers

This adds tests which will validate architecture page table helpers and
other accessors in their compliance with expected generic MM semantics.
This will help various architectures in validating changes to existing
page table helpers or addition of new ones.

This test covers basic page table entry transformations including but not
limited to old, young, dirty, clean, write, write protect etc at various
level along with populating intermediate entries with next page table page
and validating them.

Test page table pages are allocated from system memory with required size
and alignments.  The mapped pfns at page table levels are derived from a
real pfn representing a valid kernel text symbol.  This test gets called
via late_initcall().

This test gets built and run when CONFIG_DEBUG_VM_PGTABLE is selected.
Any architecture, which is willing to subscribe this test will need to
select ARCH_HAS_DEBUG_VM_PGTABLE.  For now this is limited to arc, arm64,
x86, s390 and powerpc platforms where the test is known to build and run
successfully Going forward, other architectures too can subscribe the test
after fixing any build or runtime problems with their page table helpers.

Folks interested in making sure that a given platform's page table helpers
conform to expected generic MM semantics should enable the above config
which will just trigger this test during boot.  Any non conformity here
will be reported as an warning which would need to be fixed.  This test
will help catch any changes to the agreed upon semantics expected from
generic MM and enable platforms to accommodate it thereafter.

[anshuman.khandual@arm.com: v17]
Link: http://lkml.kernel.org/r/1587436495-22033-3-git-send-email-anshuman.khandual@arm.com
[anshuman.khandual@arm.com: v18]
Link: http://lkml.kernel.org/r/1588564865-31160-3-git-send-email-anshuman.khandual@arm.com
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> [ppc32]
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Link: http://lkml.kernel.org/r/1583919272-24178-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86/mm: define mm_p4d_folded()

Patch series "mm/debug: Add tests validating architecture page table
helpers", v18.

This adds a test validation for architecture exported page table helpers.
Patch adds basic transformation tests at various levels of the page table.

This test was originally suggested by Catalin during arm64 THP migration
RFC discussion earlier.  Going forward it can include more specific tests
with respect to various generic MM functions like THP, HugeTLB etc and
platform specific tests.

https://lore.kernel.org/linux-mm/20190628102003.GA56463@arrakis.emea.arm.com/

This patch (of 2):

This just defines mm_p4d_folded() to check whether P4D page table level is
folded at runtime.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/1587436495-22033-2-git-send-email-anshuman.khandual@arm.com
Link: http://lkml.kernel.org/r/1588564865-31160-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: remove __ARCH_HAS_5LEVEL_HACK and include/asm-generic/5level-fixup.h

There are no architectures that use include/asm-generic/5level-fixup.h
therefore it can be removed along with __ARCH_HAS_5LEVEL_HACK define and
the code it surrounds

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-15-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

asm-generic: remove pgtable-nop4d-hack.h

No architecture defines __ARCH_USE_5LEVEL_HACK and therefore
pgtable-nop4d-hack.h will be never actually included.

Remove it.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-14-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

unicore32: remove __ARCH_USE_5LEVEL_HACK

The unicore32 architecture has 2 level page tables and
asm-generic/pgtable-nopmd.h and explicit casts from pud_t to pgd_t for
page table folding.

Add p4d walk in the only place that actually unfolds the pud level and
remove __ARCH_USE_5LEVEL_HACK.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-13-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sh: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate and remove usage of __ARCH_USE_5LEVEL_HACK.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-12-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sh: drop __pXd_offset() macros that duplicate pXd_index() ones

The __pXd_offset() macros are identical to the pXd_index() macros and
there is no point to keep both of them.  All architectures define and use
pXd_index() so let's keep only those to make mips consistent with the rest
of the kernel.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-11-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sh: fault: modernize printing of kernel messages

  - Convert from printk() to pr_*(),
  - Add missing continuations,
  - Use "%llx" to format u64,
  - Join multiple prints in show_fault_oops() into a single print.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-10-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

powerpc: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate and replace 5level-fixup.h with pgtable-nop4d.h.

[rppt@linux.ibm.com: powerpc/xmon: drop unused pgdir varialble in show_pte() function]
Link: http://lkml.kernel.org/r/20200519181454.GI1059226@linux.ibm.com
[rppt@linux.ibm.com; build fix]
Link: http://lkml.kernel.org/r/20200423141845.GI13521@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> # 8xx and 83xx
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-9-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

openrisc: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate and remove usage of __ARCH_USE_5LEVEL_HACK.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-8-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nios2: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate and remove usage of __ARCH_USE_5LEVEL_HACK.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-7-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ia64: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate, remove usage of __ARCH_USE_5LEVEL_HACK and
replace 5level-fixup.h with pgtable-nop4d.h

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-6-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hexagon: remove __ARCH_USE_5LEVEL_HACK

The hexagon architecture has 2 level page tables and as such most of the
page table folding is already implemented in asm-generic/pgtable-nopmd.h.

Fixup the only place in arch/hexagon to unfold the p4d level and remove
__ARCH_USE_5LEVEL_HACK.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-5-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arm64: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate, replace 5level-fixup.h with pgtable-nop4d.h and
remove __ARCH_USE_5LEVEL_HACK.

[arnd@arndb.de: fix gcc-10 shift warning]
Link: http://lkml.kernel.org/r/20200429185657.4085975-1-arnd@arndb.de
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-4-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arm: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate, and remove __ARCH_USE_5LEVEL_HACK.

[rppt@linux.ibm.com: fix kexec]
Link: http://lkml.kernel.org/r/20200508174232.GA759899@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-3-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

h8300: remove usage of __ARCH_USE_5LEVEL_HACK

Patch series "mm: remove __ARCH_HAS_5LEVEL_HACK", v4.

These patches convert several architectures to use page table folding and
remove __ARCH_HAS_5LEVEL_HACK along with
include/asm-generic/5level-fixup.h and
include/asm-generic/pgtable-nop4d-hack.h.  With that we'll have a single
and consistent way of dealing with page table folding instead of a mix of
three existing options.

The changes are mostly about mechanical replacement of pgd accessors with
p4d ones and the addition of higher levels to page table traversals.

This patch (of 14):

h8300 is a nommu architecture and does not require fixup for upper layers
of the page tables because it is already handled by the generic nommu
implementation.

Remove definition of __ARCH_USE_5LEVEL_HACK in
arch/h8300/include/asm/pgtable.h

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com> [openrisc]
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Joerg Roedel <joro@8bytes.org>
Link: http://lkml.kernel.org/r/20200414153455.21744-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200414153455.21744-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/util.c: remove the VM_WARN_ONCE for vm_committed_as underflow check

This check was added by commit 82f71ae4a2b8 ("mm: catch memory
commitment underflow") in 2014 to have a safety check for issues which
have been fixed.  And there has been few report caught by it, as
described in its commit log:

: This shouldn't happen any more - the previous two patches fixed
: the committed_as underflow issues.

But it was really found by Qian Cai when he used the LTP memory stress
suite to test a RFC patchset, which tries to improve scalability of
per-cpu counter 'vm_committed_as', by chosing a bigger 'batch' number for
loose overcommit policies (OVERCOMMIT_ALWAYS and OVERCOMMIT_GUESS), while
keeping current number for OVERCOMMIT_NEVER.

With that patchset, when system firstly uses a loose policy, the
'vm_committed_as' count could be a big negative value, as its big 'batch'
number allows a big deviation, then when the policy is changed to
OVERCOMMIT_NEVER, the 'batch' will be decreased to a much smaller value,
thus hits this WARN check.

To mitigate this, one proposed solution is to queue work on all online
CPUs to do a local sync for 'vm_committed_as' when changing policy to
OVERCOMMIT_NEVER, plus some global syncing to garante the case won't be
hit.

But this solution is costy and slow, given this check hasn't shown real
trouble or benefit, simply drop it from one hot path of MM.  And perf
stats does show some tiny saving for removing it.

Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Qian Cai <cai@lca.pw>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20200603094804.GB89848@shbuild999.sh.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

usb: core: kcov: collect coverage from usb complete callback

This patch adds kcov_remote_start/stop() callbacks around the urb
complete() callback that is executed in softirq context when dummy_hcd is
in use.  As the result, kcov can be used to collect coverage from those
callbacks, which is used to facilitate coverage-guided fuzzing with
syzkaller.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Link: http://lkml.kernel.org/r/4520671eeb604adbc2432c248b0c07fbaa5519ef.1585233617.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/2821d497ac1cdc0efb5e00df30271e4a67fc8009.1584655448.git.andreyknvl@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kcov: collect coverage from interrupts

This change extends kcov remote coverage support to allow collecting
coverage from soft interrupts in addition to kernel background threads.

To collect coverage from code that is executed in softirq context, a part
of that code has to be annotated with kcov_remote_start/stop() in a
similar way as how it is done for global kernel background threads.  Then
the handle used for the annotations has to be passed to the
KCOV_REMOTE_ENABLE ioctl.

Internally this patch adjusts the __sanitizer_cov_trace_pc() compiler
inserted callback to not bail out when called from softirq context.
kcov_remote_start/stop() are updated to save/restore the current per task
kcov state in a per-cpu area (in case the softirq came when the kernel was
already collecting coverage in task context).  Coverage from softirqs is
collected into pre-allocated per-cpu areas, whose size is controlled by
the new CONFIG_KCOV_IRQ_AREA_SIZE.

[andreyknvl@google.com: turn current->kcov_softirq into unsigned int to fix objtool warning]
Link: http://lkml.kernel.org/r/841c778aa3849c5cb8c3761f56b87ce653a88671.1585233617.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Link: http://lkml.kernel.org/r/469bd385c431d050bc38a593296eff4baae50666.1584655448.git.andreyknvl@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kcov: use t->kcov_mode as enabled indicator

Currently kcov_remote_start() and kcov_remote_stop() check t->kcov to find
out whether the coverage is already being collected by the current task.
Use t->kcov_mode for that instead.  This doesn't change the overall
behavior in any way, but serves as a preparation for the following softirq
coverage collection support patch.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Link: http://lkml.kernel.org/r/f70377945d1d8e6e4916cbce871a12303d6186b4.1585233617.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/ee1a1dec43059da5d7664c85c1addc89c4cd58de.1584655448.git.andreyknvl@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kcov: move t->kcov_sequence assignment

Move t->kcov_sequence assignment before assigning t->kcov_mode for
consistency.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Link: http://lkml.kernel.org/r/5889efe35e0b300e69dba97216b1288d9c2428a8.1585233617.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/f0283c676bab3335cb48bfe12d375a3da4719f59.1584655448.git.andreyknvl@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kcov: move t->kcov assignments into kcov_start/stop

Every time kcov_start/stop() is called, t->kcov is also assigned, so move
the assignment into the functions.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Link: http://lkml.kernel.org/r/6644839d3567df61ade3c4b246a46cacbe4f9e11.1585233617.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/82625ef3ff878f0b585763cc31d09d9b08ca37d6.1584655448.git.andreyknvl@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kcov: fix potential use-after-free in kcov_remote_start

If vmalloc() fails in kcov_remote_start() we'll access remote->kcov
without holding kcov_remote_lock, so remote might potentially be freed at
that point.  Cache kcov pointer in a local variable.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Link: http://lkml.kernel.org/r/9d9134359725a965627b7e8f2652069f86f1d1fa.1585233617.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/de0d3d30ff90776a2a509cc34c7c1c7521bda125.1584655448.git.andreyknvl@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kcov: cleanup debug messages

Patch series "kcov: collect coverage from usb soft interrupts", v4.

This patchset extends kcov to allow collecting coverage from soft
interrupts and then uses the new functionality to collect coverage from
USB code.

This has allowed to find at least one new HID bug [1], which was recently
fixed by Alan [2].

[1] https://syzkaller.appspot.com/bug?extid=09ef48aa58261464b621
[2] https://patchwork.kernel.org/patch/11283319/

Any subsystem that uses softirqs (e.g. timers) can make use of this in
the future. Looking at the recent syzbot reports, an obvious candidate
is the networking subsystem [3, 4, 5 and many more].

[3] https://syzkaller.appspot.com/bug?extid=522ab502c69badc66ab7
[4] https://syzkaller.appspot.com/bug?extid=57f89d05946c53dbbb31
[5] https://syzkaller.appspot.com/bug?extid=df358e65d9c1b9d3f5f4

This pach (of 7):

Previous commit left a lot of excessive debug messages, clean them up.

Link; http://lkml.kernel.org/r/cover.1585233617.git.andreyknvl@google.com
Link; http://lkml.kernel.org/r/ab5e2885ce674ba6e04368551e51eeb6a2c11baf.1585233617.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Link: http://lkml.kernel.org/r/4a497134b2cf7a9d306d28e3dd2746f5446d1605.1584655448.git.andreyknvl@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: Fix mremap not considering huge pmd devmap

The original code in mm/mremap.c checks huge pmd by:

if (is_swap_pmd(*old_pmd) || pmd_trans_huge(*old_pmd)) {

However, a DAX mapped nvdimm is mapped as huge page (by default) but it
is not transparent huge page (_PAGE_PSE | PAGE_DEVMAP).  This commit
changes the condition to include the case.

This addresses CVE-2020-10757.

Fixes: 5c7fb56e5e3f ("mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd")
Cc: <stable@vger.kernel.org>
Reported-by: Fan Yang <Fan_Yang@sjtu.edu.cn>
Signed-off-by: Fan Yang <Fan_Yang@sjtu.edu.cn>
Tested-by: Fan Yang <Fan_Yang@sjtu.edu.cn>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge branch 'exec-linus' of git://git./linux/kernel/git/ebiederm/user-namespace

Pull execve updates from Eric Biederman:
 "Last cycle for the Nth time I ran into bugs and quality of
  implementation issues related to exec that could not be easily be
  fixed because of the way exec is implemented. So I have been digging
  into exec and cleanup up what I can.

  I don't think I have exec sorted out enough to fix the issues I
  started with but I have made some headway this cycle with 4 sets of
  changes.

   - promised cleanups after introducing exec_update_mutex

   - trivial cleanups for exec

   - control flow simplifications

   - remove the recomputation of bprm->cred

  The net result is code that is a bit easier to understand and work
  with and a decrease in the number of lines of code (if you don't count
  the added tests)"

* 'exec-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (24 commits)
  exec: Compute file based creds only once
  exec: Add a per bprm->file version of per_clear
  binfmt_elf_fdpic: fix execfd build regression
  selftests/exec: Add binfmt_script regression test
  exec: Remove recursion from search_binary_handler
  exec: Generic execfd support
  exec/binfmt_script: Don't modify bprm->buf and then return -ENOEXEC
  exec: Move the call of prepare_binprm into search_binary_handler
  exec: Allow load_misc_binary to call prepare_binprm unconditionally
  exec: Convert security_bprm_set_creds into security_bprm_repopulate_creds
  exec: Factor security_bprm_creds_for_exec out of security_bprm_set_creds
  exec: Teach prepare_exec_creds how exec treats uids & gids
  exec: Set the point of no return sooner
  exec: Move handling of the point of no return to the top level
  exec: Run sync_mm_rss before taking exec_update_mutex
  exec: Fix spelling of search_binary_handler in a comment
  exec: Move the comment from above de_thread to above unshare_sighand
  exec: Rename flush_old_exec begin_new_exec
  exec: Move most of setup_new_exec into flush_old_exec
  exec: In setup_new_exec cache current in the local variable me
  ...

Merge branch 'proc-linus' of git://git./linux/kernel/git/ebiederm/user-namespace

Pull proc updates from Eric Biederman:
 "This has four sets of changes:

   - modernize proc to support multiple private instances

   - ensure we see the exit of each process tid exactly

   - remove has_group_leader_pid

   - use pids not tasks in posix-cpu-timers lookup

  Alexey updated proc so each mount of proc uses a new superblock. This
  allows people to actually use mount options with proc with no fear of
  messing up another mount of proc. Given the kernel's internal mounts
  of proc for things like uml this was a real problem, and resulted in
  Android's hidepid mount options being ignored and introducing security
  issues.

  The rest of the changes are small cleanups and fixes that came out of
  my work to allow this change to proc. In essence it is swapping the
  pids in de_thread during exec which removes a special case the code
  had to handle. Then updating the code to stop handling that special
  case"

* 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  proc: proc_pid_ns takes super_block as an argument
  remove the no longer needed pid_alive() check in __task_pid_nr_ns()
  posix-cpu-timers: Replace __get_task_for_clock with pid_for_clock
  posix-cpu-timers: Replace cpu_timer_pid_type with clock_pid_type
  posix-cpu-timers: Extend rcu_read_lock removing task_struct references
  signal: Remove has_group_leader_pid
  exec: Remove BUG_ON(has_group_leader_pid)
  posix-cpu-timer:  Unify the now redundant code in lookup_task
  posix-cpu-timer: Tidy up group_leader logic in lookup_task
  proc: Ensure we see the exit of each process tid exactly once
  rculist: Add hlists_swap_heads_rcu
  proc: Use PIDTYPE_TGID in next_tgid
  Use proc_pid_ns() to get pid_namespace from the proc superblock
  proc: use named enums for better readability
  proc: use human-readable values for hidepid
  docs: proc: add documentation for "hidepid=4" and "subset=pid" options and new mount behavior
  proc: add option to mount only a pids subset
  proc: instantiate only pids that we can ptrace on 'hidepid=4' mount option
  proc: allow to mount many instances of proc in one pid namespace
  proc: rename struct proc_fs_info to proc_fs_opts

Merge tag 'for_v5.8-rc1' of git://git./linux/kernel/git/jack/linux-fs

Pull ext2 and reiserfs cleanups from Jan Kara:
 "Two small cleanups for ext2 and one for reiserfs"

* tag 'for_v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  reiserfs: Replace kmalloc with kcalloc in the comment
  ext2: code cleanup by removing ifdef macro surrounding
  ext2: Fix i_op setting for special inode

Merge tag 'fsnotify_for_v5.8-rc1' of git://git./linux/kernel/git/jack/linux-fs

Pull fsnotify updates from Jan Kara:
 "Several smaller fixes and cleanups for fsnotify subsystem"

* tag 'fsnotify_for_v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fanotify: fix ignore mask logic for events on child and on dir
  fanotify: don't write with size under sizeof(response)
  fsnotify: Remove proc_fs.h include
  fanotify: remove reference to fill_event_metadata()
  fsnotify: add mutex destroy
  fanotify: prefix should_merge()
  fanotify: Replace zero-length array with flexible-array
  inotify: Fix error return code assignment flow.
  fsnotify: Add missing annotation for fsnotify_finish_user_wait() and for fsnotify_prepare_user_wait()

Merge tag 'zonefs-5.8-rc1' of git://git./linux/kernel/git/dlemoal/zonefs

Pull zonefs update from Damien Le Moal:
 "Only one patch in this pull request to cleanup handling of uuid using
  the import_uuid() helper, from Andy"

* tag 'zonefs-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs:
  zonefs: Replace uuid_copy() with import_uuid()

Merge branch 'for-linus' of git://git./linux/kernel/git/livepatching/livepatching

Pull livepatching updates from Jiri Kosina:

 - simplifications and improvements for issues Peter Ziljstra found
   during his previous work on W^X cleanups.

   This allows us to remove livepatch arch-specific .klp.arch sections
   and add proper support for jump labels in patched code.

   Also, this patchset removes the last module_disable_ro() usage in the
   tree.

   Patches from Josh Poimboeuf and Peter Zijlstra

 - a few other minor cleanups

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
  MAINTAINERS: add lib/livepatch to LIVE PATCHING
  livepatch: add arch-specific headers to MAINTAINERS
  livepatch: Make klp_apply_object_relocs static
  MAINTAINERS: adjust to livepatch .klp.arch removal
  module: Make module_enable_ro() static again
  x86/module: Use text_mutex in apply_relocate_add()
  module: Remove module_disable_ro()
  livepatch: Remove module_disable_ro() usage
  x86/module: Use text_poke() for late relocations
  s390/module: Use s390_kernel_write() for late relocations
  s390: Change s390_kernel_write() return type to match memcpy()
  livepatch: Prevent module-specific KLP rela sections from referencing vmlinux symbols
  livepatch: Remove .klp.arch
  livepatch: Apply vmlinux-specific KLP relocations early
  livepatch: Disallow vmlinux.ko

Merge branch 'for-linus' of git://git./linux/kernel/git/hid/hid

Pull HID updates from Jiri Kosina:

 - hid-mcp2221 GPIO support, from Rishi Gupta

 - MT_CLS_WIN_8_DUAL obsolete quirk removal from hid-multitouch, from
   Kai-Heng Feng

 - a bunch of new hardware support to hid-asus driver, from Hans de
   Goede

 - other assorted small fixes, cleanups and device-specific quirks

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid:
  HID: multitouch: Remove MT_CLS_WIN_8_DUAL
  HID: multitouch: enable multi-input as a quirk for some devices
  HID: sony: Fix for broken buttons on DS3 USB dongles
  HID: Add quirks for Trust Panora Graphic Tablet
  HID: apple: Swap the Fn and Left Control keys on Apple keyboards
  HID: asus: Add depends on USB_HID to HID_ASUS Kconfig option
  HID: asus: Fix mute and touchpad-toggle keys on Medion Akoya E1239T
  HID: asus: Add support for multi-touch touchpad on Medion Akoya E1239T
  HID: asus: Add report_size to struct asus_touchpad_info
  HID: asus: Add hid_is_using_ll_driver(usb_hid_driver) check
  HID: asus: Simplify skipping of mappings for Asus T100CHI keyboard-dock
  HID: asus: Only set EV_REP if we are adding a mapping
  HID: i2c-hid: add Schneider SCL142ALM to descriptor override
  HID: intel-ish-hid: avoid bogus uninitialized-variable warning
  HID: mcp2221: add GPIO functionality support
  HID: fix typo in Kconfig
  HID: logitech: drop outdated references to unifying receivers

Merge tag 'sound-5.8-rc1' of git://git./linux/kernel/git/tiwai/sound

Pull sound updates from Takashi Iwai:
 "It was another busy development cycle, and the majority of changes are
  found in ASoC side. Below are Some highlights.

  ASoC core:
   - Lots of core cleanups and refactorings, still on-going work by
     Morimoto-san

  ASoC drivers:
   - Continued work on cleaning up and improving the Intel SOF stuff,
     along with new platform support including SoundWire

   - Fixes to make the Marvell SSPA driver work upstream

   - Support for AMD Renoir ACP, Dialog DA7212, Freescale EASRC and
     i.MX8M, Intel Elkhard Lake, Maxim MAX98390, Nuvoton NAU8812 and
     NAU8814 and Realtek RT1016.

  USB-audio:
   - Improvement for sync and implicit feedback streams with the more
     accurate frame size calculation and full-duplex support

   - Support for RME Babyface Pro and Prioneer DJ DJM

  HD-audio:
   - Fixes for Mic mute LED on HP machines

   - Re-enable support of Intel SST driver for SKL/KBL platforms

  FireWire:
   - Lots of refactoring, add support for RME FireFace and MOTU
     UltraLite-mk3"

* tag 'sound-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (428 commits)
  ALSA: es1688: Add the missed snd_card_free()
  ALSA: hda: add sienna_cichlid audio asic id for sienna_cichlid up
  ALSA: usb-audio: Add Pioneer DJ DJM-900NXS2 support
  ASoC: qcom: q6asm-dai: kCFI fix
  ASoC: soc-card: add snd_soc_card_remove_dai_link()
  ASoC: soc-card: add snd_soc_card_add_dai_link()
  ASoC: soc-card: add snd_soc_card_set_bias_level_post()
  ASoC: soc-card: add snd_soc_card_set_bias_level()
  ASoC: soc-card: add snd_soc_card_remove()
  ASoC: soc-card: add snd_soc_card_late_probe()
  ASoC: soc-card: add snd_soc_card_probe()
  ASoC: soc-card: add probed bit field to snd_soc_card
  ASoC: soc-card: add snd_soc_card_resume_post()
  ASoC: soc-card: add snd_soc_card_resume_pre()
  ASoC: soc-card: add snd_soc_card_suspend_post()
  ASoC: soc-card: add snd_soc_card_suspend_pre()
  ASoC: soc-card: move snd_soc_card_subclass to soc-card
  ASoC: soc-card: move snd_soc_card_get_codec_dai() to soc-card
  ASoC: soc-card: move snd_soc_card_set/get_drvdata() to soc-card
  ASoC: soc-card: move snd_soc_card_jack_new() to soc-card
  ...

Merge branch 'pcmcia-next' of git://git./linux/kernel/git/brodo/linux

Pull pcmcia updates from Dominik Brodowski:
 "Two minor PCMCIA odd fixes: one replacing zero-length arrays with a
  flexible-array member, and one making a local function static"

* 'pcmcia-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux:
  pcmcia: make pccard_loop_tuple() static
  pcmcia: Replace zero-length array with flexible-array

Merge tag 'leds-5.8-rc1' of git://git./linux/kernel/git/pavel/linux-leds

Pull LED updates from Pavel Machek:
 "New drivers: aw2013, sgm3140, some fixes

  Nothing much to see here, next release should be more interesting"

* tag 'leds-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/pavel/linux-leds:
  leds: add aw2013 driver
  dt-bindings: leds: Add binding for aw2013
  leds: trigger: remove redundant assignment to variable ret
  leds: netxbig: Convert to use GPIO descriptors
  leds: add sgm3140 driver
  dt-bindings: leds: Add binding for sgm3140
  leds: ariel: Add driver for status LEDs on Dell Wyse 3020
  leds: pwm: check result of led_pwm_set() in led_pwm_add()
  leds: tlc591xxt: hide error on EPROBE_DEFER
  leds: tca6507: Include the right header
  leds: lt3593: Drop surplus include
  leds: lp3952: Include the right header
  leds: lm355x: Drop surplus include

Merge tag 'tag-chrome-platform-for-v5.8' of git://git./linux/kernel/git/chrome-platform/linux

Pull chrome platform updates from Benson Leung:
 "cros_ec_typec:
   - Add notifier for update, and register port partner

  Sensors/iio:
   - Fixes to cros_ec_sensorhub around allocation of resources, and
     send_sample

  Wilco EC:
   - Fix to output format of h1_gpio

  Misc:
   - Misc fixes to appease kernel-doc and other warnings
   - Set user space log size in chromeos_pstore"

* tag 'tag-chrome-platform-for-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux:
  platform/chrome: cros_usbpd_logger: Add __printf annotation to append_str()
  platform/chrome: cros_ec_i2c: Appease the kernel-doc deity
  platform/chrome: typec: Fix ret value check error
  platform/chrome: cros_ec_typec: Register port partner
  platform/chrome: cros_ec_typec: Add struct for port data
  platform/chrome: cros_ec_typec: Use notifier for updates
  platform/chrome: cros_ec_ishtp: free ishtp buffer before sending event
  platform/chrome: cros_ec_ishtp: skip old cros_ec responses
  platform/chrome: wilco_ec: Provide correct output format to 'h1_gpio' file
  platform/chrome: chromeos_pstore: set user space log size

Merge tag 'linux-watchdog-5.8-rc1' of git://linux-watchdog.org/linux-watchdog

Pull watchdog updates from Wim Van Sebroeck:

 - add new arm_smc_wdt watchdog driver

 - da9062 and da9063 improvements

 - clarify documentation about stop() that became optional

 - document r8a7742 support

 - some overall fixes and improvements

* tag 'linux-watchdog-5.8-rc1' of git://www.linux-watchdog.org/linux-watchdog:
  watchdog: m54xx: Add missing include
  dt-bindings: watchdog: renesas,wdt: Document r8a7742 support
  watchdog: Fix runtime PM imbalance on error
  watchdog: riowd: remove unneeded semicolon
  watchdog: Add new arm_smc_wdt watchdog driver
  dt-bindings: watchdog: Add ARM smc wdt for mt8173 watchdog
  watchdog: imx2_wdt: update contact email
  watchdog: iTCO: fix link error
  watchdog: da9062: No need to ping manually before setting timeout
  watchdog: da9063: Make use of pre-configured timeout during probe
  watchdog: da9062: Initialize timeout during probe
  watchdog: clarify that stop() is optional
  watchdog: imx_sc_wdt: Fix reboot on crash
  watchdog: ts72xx_wdt: fix build error

Merge tag 'backlight-next-5.8' of git://git./linux/kernel/git/lee/backlight

Pull backlight updates from Lee Jones:
 "Core Framework:
   - Add backlight_device_get_by_name() to the API

  New Device Support:
   - Add support for WLED5 to Qualcomm WLED

  Fix-ups:
   - Convert to GPIO descriptors in l4f00242t03
   - Device Tree fix-ups for qcom-wled

  Bug Fixes:
   - Properly disable regulators on .probe() failure"

* tag 'backlight-next-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: Add backlight_device_get_by_name()
  backlight: qcom-wled: Add support for WLED5 peripheral that is present on PM8150L PMICs
  dt-bindings: backlight: qcom-wled: Add WLED5 bindings
  backlight: qcom-wled: Add callback functions
  dt-bindings: backlight: qcom-wled: Convert the wled bindings to .yaml format
  backlight: l4f00242t03: Convert to GPIO descriptors
  backlight: lp855x: Ensure regulators are disabled on probe failure

Merge tag 'mfd-next-5.8' of git://git./linux/kernel/git/lee/mfd

Pull MFD updates from Lee Jones:
 "Core Frameworks:
   - Constify 'properties' attribute in core header file

  New Drivers:
   - Add support for Gateworks System Controller
   - Add support for MediaTek MT6358 PMIC
   - Add support for Mediatek MT6360 PMIC
   - Add support for Monolithic Power Systems MP2629 ADC and Battery charger

  Fix-ups:
   - Use new I2C API in htc-i2cpld
   - Remove superfluous code in sprd-sc27xx-spi
   - Improve error handling in stm32-timers
   - Device Tree additions/fixes in mt6397
   - Defer probe betterment in wm8994-core
   - Improve module handling in wm8994-core
   - Staticify in stpmic1
   - Trivial (spelling, formatting) in tqmx86

  Bug Fixes:
   - Fix incorrect register/PCI IDs in intel-lpss-pci
   - Fix unbalanced Regulator API calls in wm8994-core
   - Fix double free() in wcd934x
   - Remove IRQ domain on failure in stmfx
   - Reset chip on resume in stmfx
   - Disable/enable IRQs on suspend/resume in stmfx
   - Do not use bulk writes on H/W which does not support them in max77620"

* tag 'mfd-next-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd: (29 commits)
  mfd: mt6360: Remove duplicate REGMAP_IRQ_REG_LINE() entry
  mfd: Add support for PMIC MT6360
  mfd: max77620: Use single-byte writes on MAX77620
  mfd: wcd934x: Drop kfree for memory allocated with devm_kzalloc
  mfd: stmfx: Disable IRQ in suspend to avoid spurious interrupt
  mfd: stmfx: Fix stmfx_irq_init error path
  mfd: stmfx: Reset chip on resume as supply was disabled
  mfd: wm8994: Silence warning about supplies during deferred probe
  mfd: wm8994: Fix unbalanced calls to regulator_bulk_disable()
  mfd: wm8994: Fix driver operation if loaded as modules
  dt-bindings: mfd: mediatek: Add MT6397 Pin Controller
  mfd: Constify properties in mfd_cell
  mfd: stm32-timers: Use dma_request_chan() instead dma_request_slave_channel()
  mfd: sprd: Remove unnecessary spi_bus_type setting
  mfd: intel-lpss: Update LPSS UART #2 PCI ID for Jasper Lake
  mfd: tqmx86: Fix a typo in MODULE_DESCRIPTION
  mfd: stpmic1: Make stpmic1_regmap_config static
  mfd: htc-i2cpld: Convert to use i2c_new_client_device()
  MAINTAINERS: Add entry for mp2629 Battery Charger driver
  power: supply: mp2629: Add impedance compensation config
  ...

Merge tag 'Smack-for-5.8' of git://github.com/cschaufler/smack-next

Pull smack updates from Casey Schaufler:
 "Clean out dead code and repair an out-of-bounds warning"

* tag 'Smack-for-5.8' of git://github.com/cschaufler/smack-next:
  Smack: Remove unused inline function smk_ad_setfield_u_fs_path_mnt
  Smack:- Remove redundant inode_smack cache
  Smack:- Remove mutex lock "smk_lock" from inode_smack
  Smack: slab-out-of-bounds in vsscanf
  smack: remove redundant structure variable from header.
  smack: avoid unused 'sip' variable warning

Merge tag 'keys-next-20200602' of git://git./linux/kernel/git/dhowells/linux-fs

Pull keyring updates from David Howells:

 - Fix a documentation warning.

 - Replace a zero-length array with a flexible one

 - Make the big_key key type use ChaCha20Poly1305 and use the crypto
   algorithm directly rather than going through the crypto layer.

 - Implement the update op for the big_key type.

* tag 'keys-next-20200602' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  keys: Implement update for the big_key type
  security/keys: rewrite big_key crypto to use library interface
  KEYS: Replace zero-length array with flexible-array
  Documentation: security: core.rst: add missing argument

Merge tag 'perf-tools-2020-06-02' of git://git./linux/kernel/git/acme/linux

Pull perf tooling updates from Arnaldo Carvalho de Melo:
 "These are additional changes to the perf tools, on top of what Ingo
  already submitted.

   - Further Intel PT call-trace fixes

   - Improve SELinux docs and tool warnings

   - Fix race at exit in 'perf record' using eventfd.

   - Add missing build tests to the default set of 'make -C tools/perf
     build-test'

   - Sync msr-index.h getting new AMD MSRs to decode and filter in 'perf
     trace'.

   - Fix fallback to libaudit in 'perf trace' for arches not using
     per-arch *.tbl files.

   - Fixes for 'perf ftrace'.

   - Fixes and improvements for the 'perf stat' metrics.

   - Use dummy event to get PERF_RECORD_{FORK,MMAP,etc} while
     synthesizing those metadata events for pre-existing threads.

   - Fix leaks detected using clang tooling.

   - Improvements to PMU event metric testing.

   - Report summary for 'perf stat' interval mode at the end, summing up
     all the intervals.

   - Improve pipe mode, i.e. this now works as expected, continuously
     dumping samples:

        # perf record -g -e raw_syscalls:sys_enter | perf --no-pager script

   - Fixes for event grouping, detecting incompatible groups such as:

        # perf stat -e '{cycles,power/energy-cores/}' -v
        WARNING: group events cpu maps do not match, disabling group:
          anon group { power/energy-cores/, cycles }
            power/energy-cores/: 0
            cycles: 0-7

   - Fixes for 'perf probe': blacklist address checking, number of
     kretprobe instances, etc.

   - JIT processing improvements and fixes plus the addition of a 'perf
     test' entry for the java demangler.

   - Add support for synthesizing first/last level cache, TLB and remove
     access events from HW tracing in the auxtrace code, first to use is
     ARM SPE.

   - Vendor events updates and fixes, including for POWER9 and Intel.

   - Allow using ~/.perfconfig for removing the ',' separators in 'perf
     stat' output.

   - Opt-in support for libpfm4"

* tag 'perf-tools-2020-06-02' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (120 commits)
  perf tools: Remove some duplicated includes
  perf symbols: Fix kernel maps for kcore and eBPF
  tools arch x86: Sync the msr-index.h copy with the kernel sources
  perf stat: Ensure group is defined on top of the same cpu mask
  perf libdw: Fix off-by 1 relative directory includes
  perf arm-spe: Support synthetic events
  perf auxtrace: Add four itrace options
  perf tools: Move arm-spe-pkt-decoder.h/c to the new dir
  perf test: Initialize memory in dwarf-unwind
  perf tests: Don't tail call optimize in unwind test
  tools compiler.h: Add attribute to disable tail calls
  perf build: Add a LIBPFM4=1 build test entry
  perf tools: Add optional support for libpfm4
  perf tools: Correct license on jsmn JSON parser
  perf jit: Fix inaccurate DWARF line table
  perf jvmti: Remove redundant jitdump line table entries
  perf build: Add NO_SDT=1 to the default set of build tests
  perf build: Add NO_LIBCRYPTO=1 to the default set of build tests
  perf build: Add NO_SYSCALL_TABLE=1 to the build tests
  perf build: Remove libaudit from the default feature checks
  ...

atomisp: avoid warning about unused function

The atomisp_mrfld_power() function isn't actually ever called, because
the two call-sites have commented out the use because it breaks on some
platforms.  That results in:

  drivers/staging/media/atomisp/pci/atomisp_v4l2.c:764:12: warning: ‘atomisp_mrfld_power’ defined but not used [-Wunused-function]
    764 | static int atomisp_mrfld_power(struct atomisp_device *isp, bool enable)
        |            ^~~~~~~~~~~~~~~~~~~

during the build.

Rather than commenting out the use entirely, just disable it
semantically instead (using a "0 &&" construct), leaving the call in
place from a syntax standpoint, and avoiding the warning.

I really don't want my builds to have any warnings that can then hide
real issues.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'media/v5.8-1' of git://git./linux/kernel/git/mchehab/linux-media

Pull media updates from Mauro Carvalho Chehab:

 - Media documentation is now split into admin-guide, driver-api and
   userspace-api books (a longstanding request from Jon);

 - The media Kconfig was reorganized, in order to make easier to select
   drivers and their dependencies;

 - The testing drivers now has a separate directory;

 - added a new driver for Rockchip Video Decoder IP;

 - The atomisp staging driver was resurrected. It is meant to work with
   4 generations of cameras on Atom-based laptops, tablets and cell
   phones. So, it seems worth investing time to cleanup this driver and
   making it in good shape.

 - Added some V4L2 core ancillary routines to help with h264 codecs;

 - Added an ov2740 image sensor driver;

 - The si2157 gained support for Analog TV, which, in turn, added
   support for some cx231xx and cx23885 boards to also support analog
   standards;

 - Added some V4L2 controls (V4L2_CID_CAMERA_ORIENTATION and
   V4L2_CID_CAMERA_SENSOR_ROTATION) to help identifying where the camera
   is located at the device;

 - VIDIOC_ENUM_FMT was extended to support MC-centric devices;

 - Lots of drivers improvements and cleanups.

* tag 'media/v5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (503 commits)
  media: Documentation: media: Refer to mbus format documentation from CSI-2 docs
  media: s5k5baf: Replace zero-length array with flexible-array
  media: i2c: imx219: Drop <linux/clk-provider.h> and <linux/clkdev.h>
  media: i2c: Add ov2740 image sensor driver
  media: ov8856: Implement sensor module revision identification
  media: ov8856: Add devicetree support
  media: dt-bindings: ov8856: Document YAML bindings
  media: dvb-usb: Add Cinergy S2 PCIe Dual Port support
  media: dvbdev: Fix tuner->demod media controller link
  media: dt-bindings: phy: phy-rockchip-dphy-rx0: move rockchip dphy rx0 bindings out of staging
  media: staging: dt-bindings: phy-rockchip-dphy-rx0: remove non-used reg property
  media: atomisp: unify the version for isp2401 a0 and b0 versions
  media: atomisp: update TODO with the current data
  media: atomisp: adjust some code at sh_css that could be broken
  media: atomisp: don't produce errs for ignored IRQs
  media: atomisp: print IRQ when debugging
  media: atomisp: isp_mmu: don't use kmem_cache
  media: atomisp: add a notice about possible leak resources
  media: atomisp: disable the dynamic and reserved pools
  media: atomisp: turn on camera before setting it
  ...

Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
 "More mm/ work, plenty more to come

  Subsystems affected by this patch series: slub, memcg, gup, kasan,
  pagealloc, hugetlb, vmscan, tools, mempolicy, memblock, hugetlbfs,
  thp, mmap, kconfig"

* akpm: (131 commits)
  arm64: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
  x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
  riscv: support DEBUG_WX
  mm: add DEBUG_WX support
  drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup
  mm/thp: rename pmd_mknotpresent() as pmd_mkinvalid()
  powerpc/mm: drop platform defined pmd_mknotpresent()
  mm: thp: don't need to drain lru cache when splitting and mlocking THP
  hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs
  sparc32: register memory occupied by kernel as memblock.memory
  include/linux/memblock.h: fix minor typo and unclear comment
  mm, mempolicy: fix up gup usage in lookup_node
  tools/vm/page_owner_sort.c: filter out unneeded line
  mm: swap: memcg: fix memcg stats for huge pages
  mm: swap: fix vmstats for huge pages
  mm: vmscan: limit the range of LRU type balancing
  mm: vmscan: reclaim writepage is IO cost
  mm: vmscan: determine anon/file pressure balance at the reclaim root
  mm: balance LRU lists based on relative thrashing
  mm: only count actual rotations as LRU reclaim cost
  ...

arm64: mm: use ARCH_HAS_DEBUG_WX instead of arch defined

Extract DEBUG_WX to mm/Kconfig.debug for shared use.  Change to use
ARCH_HAS_DEBUG_WX instead of DEBUG_WX defined by arch port.

Signed-off-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/e19709e7576f65e303245fe520cad5f7bae72763.1587455584.git.zong.li@sifive.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined

Extract DEBUG_WX to mm/Kconfig.debug for shared use.  Change to use
ARCH_HAS_DEBUG_WX instead of DEBUG_WX defined by arch port.

Signed-off-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/430736828d149df3f5b462d291e845ec690e0141.1587455584.git.zong.li@sifive.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

riscv: support DEBUG_WX

Support DEBUG_WX to check whether there are mapping with write and execute
permission at the same time.

[akpm@linux-foundation.org: replace macros with C]
Signed-off-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/282e266311bced080bc6f7c255b92f87c1eb65d6.1587455584.git.zong.li@sifive.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: add DEBUG_WX support

Patch series "Extract DEBUG_WX to shared use".

Some architectures support DEBUG_WX function, it's verbatim from each
others, so extract to mm/Kconfig.debug for shared use.

PPC and ARM ports don't support generic page dumper yet, so we only
refine x86 and arm64 port in this patch series.

For RISC-V port, the DEBUG_WX support depends on other patches which
be merged already:
  - RISC-V page table dumper
  - Support strict kernel memory permissions for security

This patch (of 4):

Some architectures support DEBUG_WX function, it's verbatim from each
others.  Extract to mm/Kconfig.debug for shared use.

[akpm@linux-foundation.org: reword text, per Will Deacon & Zong Li]
Link: http://lkml.kernel.org/r/20200427194245.oxRJKj3fn%25akpm@linux-foundation.org
[zong.li@sifive.com: remove the specific name of arm64]
Link: http://lkml.kernel.org/r/3a6a92ecedc54e1d0fc941398e63d504c2cd5611.1589178399.git.zong.li@sifive.com
[zong.li@sifive.com: add MMU dependency for DEBUG_WX]
Link: http://lkml.kernel.org/r/4a674ac7863ff39ca91847b10e51209771f99416.1589178399.git.zong.li@sifive.com
Suggested-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/cover.1587455584.git.zong.li@sifive.com
Link: http://lkml.kernel.org/r/23980cd0f0e5d79e24a92169116407c75bcc650d.1587455584.git.zong.li@sifive.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup

Searching for a particular memory block by id is an O(n) operation because
each memory block's underlying device is kept in an unsorted linked list
on the subsystem bus.

We can cut the lookup cost to O(log n) if we cache each memory block
in an xarray.  This time complexity improvement is significant on
systems with many memory blocks.  For example:

1. A 128GB POWER9 VM with 256MB memblocks has 512 blocks.  With this
   change  memory_dev_init() completes ~12ms faster and walk_memory_blocks()
   completes ~12ms faster.

Before:
[    0.005042] memory_dev_init: adding memory blocks
[    0.021591] memory_dev_init: added memory blocks
[    0.022699] walk_memory_blocks: walking memory blocks
[    0.038730] walk_memory_blocks: walked memory blocks 0-511

After:
[    0.005057] memory_dev_init: adding memory blocks
[    0.009415] memory_dev_init: added memory blocks
[    0.010519] walk_memory_blocks: walking memory blocks
[    0.014135] walk_memory_blocks: walked memory blocks 0-511

2. A 256GB POWER9 LPAR with 256MB memblocks has 1024 blocks.  With
   this change memory_dev_init() completes ~88ms faster and
   walk_memory_blocks() completes ~87ms faster.

Before:
[    0.252246] memory_dev_init: adding memory blocks
[    0.395469] memory_dev_init: added memory blocks
[    0.409413] walk_memory_blocks: walking memory blocks
[    0.433028] walk_memory_blocks: walked memory blocks 0-511
[    0.433094] walk_memory_blocks: walking memory blocks
[    0.500244] walk_memory_blocks: walked memory blocks 131072-131583

After:
[    0.245063] memory_dev_init: adding memory blocks
[    0.299539] memory_dev_init: added memory blocks
[    0.313609] walk_memory_blocks: walking memory blocks
[    0.315287] walk_memory_blocks: walked memory blocks 0-511
[    0.315349] walk_memory_blocks: walking memory blocks
[    0.316988] walk_memory_blocks: walked memory blocks 131072-131583

3. A 32TB POWER9 LPAR with 256MB memblocks has 131072 blocks.  With
   this change we complete memory_dev_init() ~37 minutes faster and
   walk_memory_blocks() at least ~30 minutes faster.  The exact timing
   for walk_memory_blocks() is  missing, though I observed that the
   soft lockups in walk_memory_blocks() disappeared with the change,
   suggesting that lower bound.

Before:
[   13.703907] memory_dev_init: adding blocks
[ 2287.406099] memory_dev_init: added all blocks
[ 2347.494986] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 2527.625378] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 2707.761977] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 2887.899975] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3068.028318] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3248.158764] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3428.287296] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3608.425357] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3788.554572] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 3968.695071] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160
[ 4148.823970] [c000000014c5bb60] [c000000000869af4] walk_memory_blocks+0x94/0x160

After:
[   13.696898] memory_dev_init: adding blocks
[   15.660035] memory_dev_init: added all blocks
(the walk_memory_blocks traces disappear)

There should be no significant negative impact for machines with few
memory blocks.  A sparse xarray has a small footprint and an O(log n)
lookup is negligibly slower than an O(n) lookup for only the smallest
number of memory blocks.

1. A 16GB x86 machine with 128MB memblocks has 132 blocks.  With this
   change memory_dev_init() completes ~300us faster and walk_memory_blocks()
   completes no faster or slower.  The improvement is pretty close to noise.

Before:
[    0.224752] memory_dev_init: adding memory blocks
[    0.227116] memory_dev_init: added memory blocks
[    0.227183] walk_memory_blocks: walking memory blocks
[    0.227183] walk_memory_blocks: walked memory blocks 0-131

After:
[    0.224911] memory_dev_init: adding memory blocks
[    0.226935] memory_dev_init: added memory blocks
[    0.227089] walk_memory_blocks: walking memory blocks
[    0.227089] walk_memory_blocks: walked memory blocks 0-131

[david@redhat.com: document the locking]
Link: http://lkml.kernel.org/r/bc21eec6-7251-4c91-2f57-9a0671f8d414@redhat.com
Signed-off-by: Scott Cheloha <cheloha@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Nathan Lynch <nathanl@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Cc: Scott Cheloha <cheloha@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200121231028.13699-1-cheloha@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/thp: rename pmd_mknotpresent() as pmd_mkinvalid()

pmd_present() is expected to test positive after pmdp_mknotpresent() as
the PMD entry still points to a valid huge page in memory.
pmdp_mknotpresent() implies that given PMD entry is just invalidated from
MMU perspective while still holding on to pmd_page() referred valid huge
page thus also clearing pmd_present() test.  This creates the following
situation which is counter intuitive.

[pmd_present(pmd_mknotpresent(pmd)) = true]

This renames pmd_mknotpresent() as pmd_mkinvalid() reflecting the helper's
functionality more accurately while changing the above mentioned situation
as follows.  This does not create any functional change.

[pmd_present(pmd_mkinvalid(pmd)) = true]

This is not applicable for platforms that define own pmdp_invalidate() via
__HAVE_ARCH_PMDP_INVALIDATE.  Suggestion for renaming came during a
previous discussion here.

https://patchwork.kernel.org/patch/11019637/

[anshuman.khandual@arm.com: change pmd_mknotvalid() to pmd_mkinvalid() per Will]
Link: http://lkml.kernel.org/r/1587520326-10099-3-git-send-email-anshuman.khandual@arm.com
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Link: http://lkml.kernel.org/r/1584680057-13753-3-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

powerpc/mm: drop platform defined pmd_mknotpresent()

Patch series "mm/thp: Rename pmd_mknotpresent() as pmd_mknotvalid()", v2.

This series renames pmd_mknotpresent() as pmd_mknotvalid().  Before that
it drops an existing pmd_mknotpresent() definition from powerpc platform
which was never required as it defines it's pmdp_invalidate() through
subscribing __HAVE_ARCH_PMDP_INVALIDATE.  This does not create any
functional change.

This rename was suggested by Catalin during a previous discussion while we
were trying to change the THP helpers on arm64 platform for migration.

https://patchwork.kernel.org/patch/11019637/

This patch (of 2):

Platform needs to define pmd_mknotpresent() for generic pmdp_invalidate()
only when __HAVE_ARCH_PMDP_INVALIDATE is not subscribed.  Otherwise
platform specific pmd_mknotpresent() is not required.  Hence just drop it.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1587520326-10099-1-git-send-email-anshuman.khandual@arm.com
Link: http://lkml.kernel.org/r/1584680057-13753-1-git-send-email-anshuman.khandual@arm.com
Link: http://lkml.kernel.org/r/1584680057-13753-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: thp: don't need to drain lru cache when splitting and mlocking THP

Since commit 8f182270dfec ("mm/swap.c: flush lru pvecs on compound page
arrival") THP would not stay in pagevec anymore.  So the optimization made
by commit d965432234db ("thp: increase split_huge_page() success rate")
doesn't make sense anymore, which tries to unpin munlocked THPs from
pagevec by draining pagevec.

Draining lru cache before isolating THP in mlock path is also unnecessary.
b676b293fb48 ("mm, thp: fix mapped pages avoiding unevictable list on
mlock") added it and 9a73f61bdb8a ("thp, mlock: do not mlock PTE-mapped
file huge pages") accidentally carried it over after the above
optimization went in.

Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Link: http://lkml.kernel.org/r/1585946493-7531-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs

In a 32-bit program, running on arm64 architecture.  When the address
space below mmap base is completely exhausted, shmat() for huge pages will
return ENOMEM, but shmat() for normal pages can still success on no-legacy
mode.  This seems not fair.

For normal pages, the calling trace of get_unmapped_area() is:

=> mm->get_unmapped_area()
if on legacy mode,
=> arch_get_unmapped_area()
=> vm_unmapped_area()
if on no-legacy mode,
=> arch_get_unmapped_area_topdown()
=> vm_unmapped_area()

For huge pages, the calling trace of get_unmapped_area() is:

=> file->f_op->get_unmapped_area()
=> hugetlb_get_unmapped_area()
=> vm_unmapped_area()

To solve this issue, we only need to make hugetlb_get_unmapped_area() take
the same way as mm->get_unmapped_area().  Add *bottomup() and *topdown()
for hugetlbfs, and check current mm->get_unmapped_area() to decide which
one to use.  If mm->get_unmapped_area is equal to
arch_get_unmapped_area_topdown(), hugetlb_get_unmapped_area() calls
topdown routine, otherwise calls bottomup routine.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Shijie Hu <hushijie3@huawei.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Will Deacon <will@kernel.org>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: yangerkun <yangerkun@huawei.com>
Cc: ChenGang <cg.chen@huawei.com>
Cc: Chen Jie <chenjie6@huawei.com>
Link: http://lkml.kernel.org/r/20200518065338.113664-1-hushijie3@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sparc32: register memory occupied by kernel as memblock.memory

sparc32 never registered the memory occupied by the kernel image with
memblock_add() and it only reserved this memory with meblock_reserve().

With openbios as system firmware, the memory occupied by the kernel is
reserved in openbios and removed from mem.available.  The prom setup code
in the kernel uses mem.available to set up the memory banks and
essentially there is a hole for the memory occupied by the kernel image.

Later in bootmem_init() this memory is memblock_reserve()d.

Up until recently, memmap initialization would call __init_single_page()
for the pages in that hole, the free_low_memory_core_early() would mark
them as reserved and everything would be Ok.

After the change in memmap initialization introduced by the commit "mm:
memmap_init: iterate over memblock regions rather that check each PFN",
the hole is skipped and the page structs for it are not initialized.  And
when they are passed from memblock to page allocator as reserved, the
latter gets confused.

Simply registering the memory occupied by the kernel with memblock_add()
resolves this issue.

Tested on qemu-system-sparc with Debian Etch [1] userspace.

[1] https://people.debian.org/~aurel32/qemu/sparc/debian_etch_sparc_small.qcow2

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Guenter Roeck <linux@roeck-us.net>
Link: https://lkml.kernel.org/r/20200517000050.GA87467@roeck-us.nlllllet/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/memblock.h: fix minor typo and unclear comment

Fix a minor typo "usabe->usable" for the current discription of member
variable "memory" in struct memblock.

BTW, I think it's unclear the member variable "base" in struct
memblock_type is currently described as the physical address of memory
region, change it to base address of the region is clearer since the
variable is decorated as phys_addr_t.

Signed-off-by: chenqiwu <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Link: http://lkml.kernel.org/r/1588846952-32166-1-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm, mempolicy: fix up gup usage in lookup_node

ba841078cd05 ("mm/mempolicy: Allow lookup_node() to handle fatal signal")
has added a special casing for 0 return value because that was a possible
gup return value when interrupted by fatal signal.  This has been fixed by
ae46d2aa6a7f ("mm/gup: Let __get_user_pages_locked() return -EINTR for
fatal signal") in the mean time so ba841078cd05 can be reverted.

This patch however doesn't go all the way to revert it because the check
for 0 is wrong and confusing here.  Firstly it is inherently unsafe to
access the page when get_user_pages_locked returns 0 (aka no page
returned).

Fortunatelly this will not happen because get_user_pages_locked will not
return 0 when nr_pages > 0 unless FOLL_NOWAIT is specified which is not
the case here.  Document this potential error code in gup code while we
are at it.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Xu <peterx@redhat.com>
Link: http://lkml.kernel.org/r/20200421071026.18394-1-mhocko@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

tools/vm/page_owner_sort.c: filter out unneeded line

To see a sorted result from page_owner, there must be a tiresome
preprocessing step before running page_owner_sort.  This patch simply
filters out lines which start with "PFN" while reading the page owner
report.

Signed-off-by: Changhee Han <ch0.han@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Link: http://lkml.kernel.org/r/20200429052940.16968-1-ch0.han@lge.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: swap: memcg: fix memcg stats for huge pages

The commit 2262185c5b28 ("mm: per-cgroup memory reclaim stats") added
PGLAZYFREE, PGACTIVATE & PGDEACTIVATE stats for cgroups but missed
couple of places and PGLAZYFREE missed huge page handling. Fix that.
Also for PGLAZYFREE use the irq-unsafe function to update as the irq is
already disabled.

Fixes: 2262185c5b28 ("mm: per-cgroup memory reclaim stats")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/20200527182947.251343-1-shakeelb@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: swap: fix vmstats for huge pages

Many of the callbacks called by pagevec_lru_move_fn() does not correctly
update the vmstats for huge pages. Fix that. Also __pagevec_lru_add_fn()
use the irq-unsafe alternative to update the stat as the irqs are
already disabled.

Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/20200527182916.249910-1-shakeelb@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: vmscan: limit the range of LRU type balancing

When LRU cost only shows up on one list, we abruptly stop scanning that
list altogether.  That's an extreme reaction: by the time the other list
starts thrashing and the pendulum swings back, we may have no recent age
information on the first list anymore, and we could have significant
latencies until the scanner has caught up.

Soften this change in the feedback system by ensuring that no list
receives less than a third of overall pressure, and only distribute the
other 66% according to LRU cost.  This ensures that we maintain a minimum
rate of aging on the entire workingset while it's being pressured, while
still allowing a generous rate of convergence when the relative sizes of
the lists need to adjust.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-15-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: vmscan: reclaim writepage is IO cost

The VM tries to balance reclaim pressure between anon and file so as to
reduce the amount of IO incurred due to the memory shortage.  It already
counts refaults and swapins, but in addition it should also count
writepage calls during reclaim.

For swap, this is obvious: it's IO that wouldn't have occurred if the
anonymous memory hadn't been under memory pressure.  From a relative
balancing point of view this makes sense as well: even if anon is cold and
reclaimable, a cache that isn't thrashing may have equally cold pages that
don't require IO to reclaim.

For file writeback, it's trickier: some of the reclaim writepage IO would
have likely occurred anyway due to dirty expiration.  But not all of it -
premature writeback reduces batching and generates additional writes.
Since the flushers are already woken up by the time the VM starts writing
cache pages one by one, let's assume that we'e likely causing writes that
wouldn't have happened without memory pressure.  In addition, the per-page
cost of IO would have probably been much cheaper if written in larger
batches from the flusher thread rather than the single-page-writes from
kswapd.

For our purposes - getting the trend right to accelerate convergence on a
stable state that doesn't require paging at all - this is sufficiently
accurate.  If we later wanted to optimize for sustained thrashing, we can
still refine the measurements.

Count all writepage calls from kswapd as IO cost toward the LRU that the
page belongs to.

Why do this dynamically?  Don't we know in advance that anon pages require
IO to reclaim, and so could build in a static bias?

First, scanning is not the same as reclaiming.  If all the anon pages are
referenced, we may not swap for a while just because we're scanning the
anon list.  During this time, however, it's important that we age
anonymous memory and the page cache at the same rate so that their
hot-cold gradients are comparable.  Everything else being equal, we still
want to reclaim the coldest memory overall.

Second, we keep copies in swap unless the page changes.  If there is
swap-backed data that's mostly read (tmpfs file) and has been swapped out
before, we can reclaim it without incurring additional IO.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-14-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: vmscan: determine anon/file pressure balance at the reclaim root

We split the LRU lists into anon and file, and we rebalance the scan
pressure between them when one of them begins thrashing: if the file cache
experiences workingset refaults, we increase the pressure on anonymous
pages; if the workload is stalled on swapins, we increase the pressure on
the file cache instead.

With cgroups and their nested LRU lists, we currently don't do this
correctly.  While recursive cgroup reclaim establishes a relative LRU
order among the pages of all involved cgroups, LRU pressure balancing is
done on an individual cgroup LRU level.  As a result, when one cgroup is
thrashing on the filesystem cache while a sibling may have cold anonymous
pages, pressure doesn't get equalized between them.

This patch moves LRU balancing decision to the root of reclaim - the same
level where the LRU order is established.

It does this by tracking LRU cost recursively, so that every level of the
cgroup tree knows the aggregate LRU cost of all memory within its domain.
When the page scanner calculates the scan balance for any given individual
cgroup's LRU list, it uses the values from the ancestor cgroup that
initiated the reclaim cycle.

If one sibling is then thrashing on the cache, it will tip the pressure
balance inside its ancestors, and the next hierarchical reclaim iteration
will go more after the anon pages in the tree.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-13-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: balance LRU lists based on relative thrashing

Since the LRUs were split into anon and file lists, the VM has been
balancing between page cache and anonymous pages based on per-list ratios
of scanned vs.  rotated pages.  In most cases that tips page reclaim
towards the list that is easier to reclaim and has the fewest actively
used pages, but there are a few problems with it:

1. Refaults and LRU rotations are weighted the same way, even though
   one costs IO and the other costs a bit of CPU.

2. The less we scan an LRU list based on already observed rotations,
   the more we increase the sampling interval for new references, and
   rotations become even more likely on that list. This can enter a
   death spiral in which we stop looking at one list completely until
   the other one is all but annihilated by page reclaim.

Since commit a528910e12ec ("mm: thrash detection-based file cache sizing")
we have refault detection for the page cache.  Along with swapin events,
they are good indicators of when the file or anon list, respectively, is
too small for its workingset and needs to grow.

For example, if the page cache is thrashing, the cache pages need more
time in memory, while there may be colder pages on the anonymous list.
Likewise, if swapped pages are faulting back in, it indicates that we
reclaim anonymous pages too aggressively and should back off.

Replace LRU rotations with refaults and swapins as the basis for relative
reclaim cost of the two LRUs.  This will have the VM target list balances
that incur the least amount of IO on aggregate.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-12-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: only count actual rotations as LRU reclaim cost

When shrinking the active file list we rotate referenced pages only when
they're in an executable mapping.  The others get deactivated.  When it
comes to balancing scan pressure, though, we count all referenced pages as
rotated, even the deactivated ones.  Yet they do not carry the same cost
to the system: the deactivated page *might* refault later on, but the
deactivation is tangible progress toward freeing pages; rotations on the
other hand cost time and effort without getting any closer to freeing
memory.

Don't treat both events as equal.  The following patch will hook up LRU
balancing to cache and anon refaults, which are a much more concrete cost
signal for reclaiming one list over the other.  Thus, remove the maybe-IO
cost bias from page references, and only note the CPU cost for actual
rotations that prevent the pages from getting reclaimed.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-11-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: deactivations shouldn't bias the LRU balance

Operations like MADV_FREE, FADV_DONTNEED etc.  currently move any affected
active pages to the inactive list to accelerate their reclaim (good) but
also steer page reclaim toward that LRU type, or away from the other
(bad).

The reason why this is undesirable is that such operations are not part of
the regular page aging cycle, and rather a fluke that doesn't say much
about the remaining pages on that list; they might all be in heavy use,
and once the chunk of easy victims has been purged, the VM continues to
apply elevated pressure on those remaining hot pages.  The other LRU,
meanwhile, might have easily reclaimable pages, and there was never a need
to steer away from it in the first place.

As the previous patch outlined, we should focus on recording actually
observed cost to steer the balance rather than speculating about the
potential value of one LRU list over the other.  In that spirit, leave
explicitely deactivated pages to the LRU algorithm to pick up, and let
rotations decide which list is the easiest to reclaim.

[cai@lca.pw: fix set-but-not-used warning]
Link: http://lkml.kernel.org/r/20200522133335.GA624@Qians-MacBook-Air.local
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/20200520232525.798933-10-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: base LRU balancing on an explicit cost model

Currently, scan pressure between the anon and file LRU lists is balanced
based on a mixture of reclaim efficiency and a somewhat vague notion of
"value" of having certain pages in memory over others.  That concept of
value is problematic, because it has caused us to count any event that
remotely makes one LRU list more or less preferrable for reclaim, even
when these events are not directly comparable and impose very different
costs on the system.  One example is referenced file pages that we still
deactivate and referenced anonymous pages that we actually rotate back to
the head of the list.

There is also conceptual overlap with the LRU algorithm itself.  By
rotating recently used pages instead of reclaiming them, the algorithm
already biases the applied scan pressure based on page value.  Thus, when
rebalancing scan pressure due to rotations, we should think of reclaim
cost, and leave assessing the page value to the LRU algorithm.

Lastly, considering both value-increasing as well as value-decreasing
events can sometimes cause the same type of event to be counted twice,
i.e.  how rotating a page increases the LRU value, while reclaiming it
succesfully decreases the value.  In itself this will balance out fine,
but it quietly skews the impact of events that are only recorded once.

The abstract metric of "value", the murky relationship with the LRU
algorithm, and accounting both negative and positive events make the
current pressure balancing model hard to reason about and modify.

This patch switches to a balancing model of accounting the concrete,
actually observed cost of reclaiming one LRU over another.  For now, that
cost includes pages that are scanned but rotated back to the list head.
Subsequent patches will add consideration for IO caused by refaulting of
recently evicted pages.

Replace struct zone_reclaim_stat with two cost counters in the lruvec, and
make everything that affects cost go through a new lru_note_cost()
function.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-9-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: vmscan: drop unnecessary div0 avoidance rounding in get_scan_count()

When we calculate the relative scan pressure between the anon and file LRU
lists, we have to assume that reclaim_stat can contain zeroes.  To avoid
div0 crashes, we add 1 to all denominators like so:

        anon_prio = swappiness;
        file_prio = 200 - anon_prio;

[...]

        /*
         * The amount of pressure on anon vs file pages is inversely
         * proportional to the fraction of recently scanned pages on
         * each list that were recently referenced and in active use.
         */
        ap = anon_prio * (reclaim_stat->recent_scanned[0] + 1);
        ap /= reclaim_stat->recent_rotated[0] + 1;

        fp = file_prio * (reclaim_stat->recent_scanned[1] + 1);
        fp /= reclaim_stat->recent_rotated[1] + 1;
        spin_unlock_irq(&pgdat->lru_lock);

        fraction[0] = ap;
        fraction[1] = fp;
        denominator = ap + fp + 1;

While reclaim_stat can contain 0, it's not actually possible for ap + fp
to be 0.  One of anon_prio or file_prio could be zero, but they must still
add up to 200.  And the reclaim_stat fraction, due to the +1 in there, is
always at least 1.  So if one of the two numerators is 0, the other one
can't be.  ap + fp is always at least 1.  Drop the + 1.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-8-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: remove use-once cache bias from LRU balancing

When the splitlru patches divided page cache and swap-backed pages into
separate LRU lists, the pressure balance between the lists was biased to
account for the fact that streaming IO can cause memory pressure with a
flood of pages that are used only once.  New page cache additions would
tip the balance toward the file LRU, and repeat access would neutralize
that bias again.  This ensured that page reclaim would always go for
used-once cache first.

Since e9868505987a ("mm,vmscan: only evict file pages when we have
plenty"), page reclaim generally skips over swap-backed memory entirely as
long as there is used-once cache present, and will apply the LRU balancing
when only repeatedly accessed cache pages are left - at which point the
previous use-once bias will have been neutralized.  This makes the
use-once cache balancing bias unnecessary.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-7-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: workingset: let cache workingset challenge anon

We activate cache refaults with reuse distances in pages smaller than the
size of the total cache.  This allows new pages with competitive access
frequencies to establish themselves, as well as challenge and potentially
displace pages on the active list that have gone cold.

However, that assumes that active cache can only replace other active
cache in a competition for the hottest memory.  This is not a great
default assumption.  The page cache might be thrashing while there are
enough completely cold and unused anonymous pages sitting around that we'd
only have to write to swap once to stop all IO from the cache.

Activate cache refaults when their reuse distance in pages is smaller than
the total userspace workingset, including anonymous pages.

Reclaim can still decide how to balance pressure among the two LRUs
depending on the IO situation.  Rotational drives will prefer avoiding
random IO from swap and go harder after cache.  But fundamentally, hot
cache should be able to compete with anon pages for a place in RAM.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-6-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: fold and remove lru_cache_add_anon() and lru_cache_add_file()

They're the same function, and for the purpose of all callers they are
equivalent to lru_cache_add().

[akpm@linux-foundation.org: fix it for local_lock changes]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-5-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: allow swappiness that prefers reclaiming anon over the file workingset

With the advent of fast random IO devices (SSDs, PMEM) and in-memory swap
devices such as zswap, it's possible for swap to be much faster than
filesystems, and for swapping to be preferable over thrashing filesystem
caches.

Allow setting swappiness - which defines the rough relative IO cost of
cache misses between page cache and swap-backed pages - to reflect such
situations by making the swap-preferred range configurable.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-4-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: keep separate anon and file statistics on page reclaim activity

Having statistics on pages scanned and pages reclaimed for both anon and
file pages makes it easier to evaluate changes to LRU balancing.

While at it, clean up the stat-keeping mess for isolation, putback,
reclaim stats etc.  a bit: first the physical LRU operation (isolation and
putback), followed by vmstats, reclaim_stats, and then vm events.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-3-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: fix LRU balancing effect of new transparent huge pages

The reclaim code that balances between swapping and cache reclaim tries to
predict likely reuse based on in-memory reference patterns alone.  This
works in many cases, but when it fails it cannot detect when the cache is
thrashing pathologically, or when we're in the middle of a swap storm.

The high seek cost of rotational drives under which the algorithm evolved
also meant that mistakes could quickly result in lockups from too
aggressive swapping (which is predominantly random IO).  As a result, the
balancing code has been tuned over time to a point where it mostly goes
for page cache and defers swapping until the VM is under significant
memory pressure.

The resulting strategy doesn't make optimal caching decisions - where
optimal is the least amount of IO required to execute the workload.

The proliferation of fast random IO devices such as SSDs, in-memory
compression such as zswap, and persistent memory technologies on the
horizon, has made this undesirable behavior very noticable: Even in the
presence of large amounts of cold anonymous memory and a capable swap
device, the VM refuses to even seriously scan these pages, and can leave
the page cache thrashing needlessly.

This series sets out to address this.  Since commit ("a528910e12ec mm:
thrash detection-based file cache sizing") we have exact tracking of
refault IO - the ultimate cost of reclaiming the wrong pages.  This allows
us to use an IO cost based balancing model that is more aggressive about
scanning anonymous memory when the cache is thrashing, while being able to
avoid unnecessary swap storms.

These patches base the LRU balance on the rate of refaults on each list,
times the relative IO cost between swap device and filesystem
(swappiness), in order to optimize reclaim for least IO cost incurred.

History

I floated these changes in 2016.  At the time they were incomplete and
full of workarounds due to a lack of infrastructure in the reclaim code:
We didn't have PageWorkingset, we didn't have hierarchical cgroup
statistics, and problems with the cgroup swap controller.  As swapping
wasn't too high a priority then, the patches stalled out.  With all
dependencies in place now, here we are again with much cleaner,
feature-complete patches.

I kept the acks for patches that stayed materially the same :-)

Below is a series of test results that demonstrate certain problematic
behavior of the current code, as well as showcase the new code's more
predictable and appropriate balancing decisions.

Test #1: No convergence

This test shows an edge case where the VM currently doesn't converge at
all on a new file workingset with a stale anon/tmpfs set.

The test sets up a cold anon set the size of 3/4 RAM, then tries to
establish a new file set half the size of RAM (flat access pattern).

The vanilla kernel refuses to even scan anon pages and never converges.
The file set is perpetually served from the filesystem.

The first test kernel is with the series up to the workingset patch
applied.  This allows thrashing page cache to challenge the anonymous
workingset.  The VM then scans the lists based on the current
scanned/rotated balancing algorithm.  It converges on a stable state where
all cold anon pages are pushed out and the fileset is served entirely from
cache:

    noconverge/5.7-rc5-mm noconverge/5.7-rc5-mm-workingset
Scanned 417719308.00 (    +0.00%) 64091155.00 (   -84.66%)
Reclaimed 417711094.00 (    +0.00%) 61640308.00 (   -85.24%)
Reclaim efficiency %       100.00 (    +0.00%)       96.18 (    -3.78%)
Scanned file 417719308.00 (    +0.00%) 59211118.00 (   -85.83%)
Scanned anon 0.00 (    +0.00%)          4880037.00 (          )
Swapouts 0.00 (    +0.00%)          2439957.00 (          )
Swapins 0.00 (    +0.00%)      257.00 (          )
Refaults 415246605.00 (    +0.00%) 59183722.00 (   -85.75%)
Restore refaults 0.00 (    +0.00%)         54988252.00 (          )

The second test kernel is with the full patch series applied, which
replaces the scanned/rotated ratios with refault/swapin rate-based
balancing.  It evicts the cold anon pages more aggressively in the
presence of a thrashing cache and the absence of swapins, and so converges
with about 60% of the IO and reclaim activity:

noconverge/5.7-rc5-mm-workingset noconverge/5.7-rc5-mm-lrubalance
Scanned 64091155.00 (    +0.00%) 37579741.00 (   -41.37%)
Reclaimed 61640308.00 (    +0.00%) 35129293.00 (   -43.01%)
Reclaim efficiency %       96.18 (    +0.00%)       93.48 (    -2.78%)
Scanned file 59211118.00 (    +0.00%) 32708385.00 (   -44.76%)
Scanned anon  4880037.00 (    +0.00%)  4871356.00 (    -0.18%)
Swapouts  2439957.00 (    +0.00%)  2435565.00 (    -0.18%)
Swapins      257.00 (    +0.00%)      262.00 (    +1.94%)
Refaults 59183722.00 (    +0.00%) 32675667.00 (   -44.79%)
Restore refaults 54988252.00 (    +0.00%) 28480430.00 (   -48.21%)

We're triggering this case in host sideloading scenarios: When a host's
primary workload is not saturating the machine (primary load is usually
driven by user activity), we can optimistically sideload a batch job; if
user activity picks up and the primary workload needs the whole host
during this time, we freeze the sideload and rely on it getting pushed to
swap.  Frequently that swapping doesn't happen and the completely inactive
sideload simply stays resident while the expanding primary worklad is
struggling to gain ground.

Test #2: Kernel build

This test is a a kernel build that is slightly memory-restricted (make -j4
inside a 400M cgroup).

Despite the very aggressive swapping of cold anon pages in test #1, this
test shows that the new kernel carefully balances swap against cache
refaults when both the file and the cache set are pressured.

It shows the patched kernel to be slightly better at finding the coldest
memory from the combined anon and file set to evict under pressure.  The
result is lower aggregate reclaim and paging activity:

z     5.7-rc5-mm 5.7-rc5-mm-lrubalance
Real time    210.60 (    +0.00%)    210.97 (    +0.18%)
User time    745.42 (    +0.00%)    746.48 (    +0.14%)
System time     69.78 (    +0.00%)     69.79 (    +0.02%)
Scanned file 354682.00 (    +0.00%) 293661.00 (   -17.20%)
Scanned anon 465381.00 (    +0.00%) 378144.00 (   -18.75%)
Swapouts 185920.00 (    +0.00%) 147801.00 (   -20.50%)
Swapins  34583.00 (    +0.00%)  32491.00 (    -6.05%)
Refaults 212664.00 (    +0.00%) 172409.00 (   -18.93%)
Restore refaults  48861.00 (    +0.00%)  80091.00 (   +63.91%)
Total paging IO 433167.00 (    +0.00%) 352701.00 (   -18.58%)

Test #3: Overload

This next test is not about performance, but rather about the
predictability of the algorithm.  The current balancing behavior doesn't
always lead to comprehensible results, which makes performance analysis
and parameter tuning (swappiness e.g.) very difficult.

The test shows the balancing behavior under equivalent anon and file
input.  Anon and file sets are created of equal size (3/4 RAM), have the
same access patterns (a hot-cold gradient), and synchronized access rates.
Swappiness is raised from the default of 60 to 100 to indicate equal IO
cost between swap and cache.

With the vanilla balancing code, anon scans make up around 9% of the total
pages scanned, or a ~1:10 ratio.  This is a surprisingly skewed ratio, and
it's an outcome that is hard to explain given the input parameters to the
VM.

The new balancing model targets a 1:2 balance: All else being equal,
reclaiming a file page costs one page IO - the refault; reclaiming an anon
page costs two IOs - the swapout and the swapin.  In the test we observe a
~1:3 balance.

The scanned and paging IO numbers indicate that the anon LRU algorithm we
have in place right now does a slightly worse job at picking the coldest
pages compared to the file algorithm.  There is ongoing work to improve
this, like Joonsoo's anon workingset patches; however, it's difficult to
compare the two aging strategies when the balancing between them is
behaving unintuitively.

The slightly less efficient anon reclaim results in a deviation from the
optimal 1:2 scan ratio we would like to see here - however, 1:3 is much
closer to what we'd want to see in this test than the vanilla kernel's
aging of 10+ cache pages for every anonymous one:

overload-100/5.7-rc5-mm-workingset overload-100/5.7-rc5-mm-lrubalance-realfile
Scanned  533633725.00 (    +0.00%)   595687785.00 (   +11.63%)
Reclaimed  494325440.00 (    +0.00%)   518154380.00 (    +4.82%)
Reclaim efficiency % 92.63 (    +0.00%)  86.98 (    -6.03%)
Scanned file  484532894.00 (    +0.00%)   456937722.00 (    -5.70%)
Scanned anon   49100831.00 (    +0.00%)   138750063.00 (  +182.58%)
Swapouts    8096423.00 (    +0.00%)    48982142.00 (  +504.98%)
Swapins   10027384.00 (    +0.00%)    62325044.00 (  +521.55%)
Refaults  479819973.00 (    +0.00%)   451309483.00 (    -5.94%)
Restore refaults  426422087.00 (    +0.00%)   399914067.00 (    -6.22%)
Total paging IO  497943780.00 (    +0.00%)   562616669.00 (   +12.99%)

Test #4: Parallel IO

It's important to note that these patches only affect the situation where
the kernel has to reclaim workingset memory, which is usually a
transitionary period.  The vast majority of page reclaim occuring in a
system is from trimming the ever-expanding page cache.

These patches don't affect cache trimming behavior.  We never swap as long
as we only have use-once cache moving through the file LRU, we only
consider swapping when the cache is actively thrashing.

The following test demonstrates this.  It has an anon workingset that
takes up half of RAM and then writes a file that is twice the size of RAM
out to disk.

As the cache is funneled through the inactive file list, no anon pages are
scanned (aside from apparently some background noise of 10 pages):

  5.7-rc5-mm           5.7-rc5-mm-lrubalance
Scanned     10714722.00 (    +0.00%)        10723445.00 (    +0.08%)
Reclaimed     10703596.00 (    +0.00%)        10712166.00 (    +0.08%)
Reclaim efficiency %   99.90 (    +0.00%)      99.89 (    -0.00%)
Scanned file     10714722.00 (    +0.00%)        10723435.00 (    +0.08%)
Scanned anon    0.00 (    +0.00%)      10.00 (          )
Swapouts    0.00 (    +0.00%)       7.00 (          )
Swapins    0.00 (    +0.00%)       0.00 (    +0.00%)
Refaults   92.00 (    +0.00%)      41.00 (   -54.84%)
Restore refaults    0.00 (    +0.00%)       0.00 (    +0.00%)
Total paging IO   92.00 (    +0.00%)      48.00 (   -47.31%)

This patch (of 14):

Currently, THP are counted as single pages until they are split right
before being swapped out.  However, at that point the VM is already in the
middle of reclaim, and adjusting the LRU balance then is useless.

Always account THP by the number of basepages, and remove the fixup from
the splitting path.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-1-hannes@cmpxchg.org
Link: http://lkml.kernel.org/r/20200520232525.798933-2-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: update page->mem_cgroup stability rules

The previous patches have simplified the access rules around
page->mem_cgroup somewhat:

1. We never change page->mem_cgroup while the page is isolated by
   somebody else.  This was by far the biggest exception to our rules and
   it didn't stop at lock_page() or lock_page_memcg().

2. We charge pages before they get put into page tables now, so the
   somewhat fishy rule about "can be in page table as long as it's still
   locked" is now gone and boiled down to having an exclusive reference to
   the page.

Document the new rules.  Any of the following will stabilize the
page->mem_cgroup association:

- the page lock
- LRU isolation
- lock_page_memcg()
- exclusive access to the page

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-20-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: delete unused lrucare handling

Swapin faults were the last event to charge pages after they had already
been put on the LRU list.  Now that we charge directly on swapin, the
lrucare portion of the charge code is unused.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-19-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: document the new swap control behavior

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-18-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: charge swapin pages on instantiation

Right now, users that are otherwise memory controlled can easily escape
their containment and allocate significant amounts of memory that they're
not being charged for.  That's because swap readahead pages are not being
charged until somebody actually faults them into their page table.  This
can be exploited with MADV_WILLNEED, which triggers arbitrary readahead
allocations without charging the pages.

There are additional problems with the delayed charging of swap pages:

1. To implement refault/workingset detection for anonymous pages, we
   need to have a target LRU available at swapin time, but the LRU is not
   determinable until the page has been charged.

2. To implement per-cgroup LRU locking, we need page->mem_cgroup to be
   stable when the page is isolated from the LRU; otherwise, the locks
   change under us.  But swapcache gets charged after it's already on the
   LRU, and even if we cannot isolate it ourselves (since charging is not
   exactly optional).

The previous patch ensured we always maintain cgroup ownership records for
swap pages.  This patch moves the swapcache charging point from the fault
handler to swapin time to fix all of the above problems.

v2: simplify swapin error checking (Joonsoo)

[hughd@google.com: fix livelock in __read_swap_cache_async()]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2005212246080.8458@eggly.anvils
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-17-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: make swap tracking an integral part of memory control

Without swap page tracking, users that are otherwise memory controlled can
easily escape their containment and allocate significant amounts of memory
that they're not being charged for.  That's because swap does readahead,
but without the cgroup records of who owned the page at swapout, readahead
pages don't get charged until somebody actually faults them into their
page table and we can identify an owner task.  This can be maliciously
exploited with MADV_WILLNEED, which triggers arbitrary readahead
allocations without charging the pages.

Make swap swap page tracking an integral part of memcg and remove the
Kconfig options.  In the first place, it was only made configurable to
allow users to save some memory.  But the overhead of tracking cgroup
ownership per swap page is minimal - 2 byte per page, or 512k per 1G of
swap, or 0.04%.  Saving that at the expense of broken containment
semantics is not something we should present as a coequal option.

The swapaccount=0 boot option will continue to exist, and it will
eliminate the page_counter overhead and hide the swap control files, but
it won't disable swap slot ownership tracking.

This patch makes sure we always have the cgroup records at swapin time;
the next patch will fix the actual bug by charging readahead swap pages at
swapin time rather than at fault time.

v2: fix double swap charge bug in cgroup1/cgroup2 code gating

[hannes@cmpxchg.org: fix crash with cgroup_disable=memory]
Link: http://lkml.kernel.org/r/20200521215855.GB815153@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: http://lkml.kernel.org/r/20200508183105.225460-16-hannes@cmpxchg.org
Debugged-by: Hugh Dickins <hughd@google.com>
Debugged-by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: prepare swap controller setup for integration

A few cleanups to streamline the swap controller setup:

- Replace the do_swap_account flag with cgroup_memory_noswap. This
  brings it in line with other functionality that is usually available
  unless explicitly opted out of - nosocket, nokmem.

- Remove the really_do_swap_account flag that stores the boot option
  and is later used to switch the do_swap_account. It's not clear why
  this indirection is/was necessary. Use do_swap_account directly.

- Minor coding style polishing

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-15-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: drop unused try/commit/cancel charge API

There are no more users. RIP in peace.

[arnd@arndb.de: fix an unused-function warning]
Link: http://lkml.kernel.org/r/20200528095640.151454-1-arnd@arndb.de
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-14-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: convert anon and file-thp to new mem_cgroup_charge() API

With the page->mapping requirement gone from memcg, we can charge anon and
file-thp pages in one single step, right after they're allocated.

This removes two out of three API calls - especially the tricky commit
step that needed to happen at just the right time between when the page is
"set up" and when it's "published" - somewhat vague and fluid concepts
that varied by page type.  All we need is a freshly allocated page and a
memcg context to charge.

v2: prevent double charges on pre-allocated hugepages in khugepaged

[hannes@cmpxchg.org: Fix crash - *hpage could be ERR_PTR instead of NULL]
Link: http://lkml.kernel.org/r/20200512215813.GA487759@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/20200508183105.225460-13-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: switch to native NR_ANON_THPS counter

With rmap memcg locking already in place for NR_ANON_MAPPED, it's just a
small step to remove the MEMCG_RSS_HUGE wart and switch memcg to the
native NR_ANON_THPS accounting sites.

[hannes@cmpxchg.org: fixes]
Link: http://lkml.kernel.org/r/20200512121750.GA397968@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> [build-tested]
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-12-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: switch to native NR_ANON_MAPPED counter

Memcg maintains a private MEMCG_RSS counter.  This divergence from the
generic VM accounting means unnecessary code overhead, and creates a
dependency for memcg that page->mapping is set up at the time of charging,
so that page types can be told apart.

Convert the generic accounting sites to mod_lruvec_page_state and friends
to maintain the per-cgroup vmstat counter of NR_ANON_MAPPED.  We use
lock_page_memcg() to stabilize page->mem_cgroup during rmap changes, the
same way we do for NR_FILE_MAPPED.

With the previous patch removing MEMCG_CACHE and the private NR_SHMEM
counter, this patch finally eliminates the need to have page->mapping set
up at charge time.  However, we need to have page->mem_cgroup set up by
the time rmap runs and does the accounting, so switch the commit and the
rmap callbacks around.

v2: fix temporary accounting bug by switching rmap<->commit (Joonsoo)

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-11-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: switch to native NR_FILE_PAGES and NR_SHMEM counters

Memcg maintains private MEMCG_CACHE and NR_SHMEM counters.  This
divergence from the generic VM accounting means unnecessary code overhead,
and creates a dependency for memcg that page->mapping is set up at the
time of charging, so that page types can be told apart.

Convert the generic accounting sites to mod_lruvec_page_state and friends
to maintain the per-cgroup vmstat counters of NR_FILE_PAGES and NR_SHMEM.
The page is already locked in these places, so page->mem_cgroup is stable;
we only need minimal tweaks of two mem_cgroup_migrate() calls to ensure
it's set up in time.

Then replace MEMCG_CACHE with NR_FILE_PAGES and delete the private
NR_SHMEM accounting sites.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-10-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: prepare cgroup vmstat infrastructure for native anon counters

Anonymous compound pages can be mapped by ptes, which means that if we
want to track NR_MAPPED_ANON, NR_ANON_THPS on a per-cgroup basis, we have
to be prepared to see tail pages in our accounting functions.

Make mod_lruvec_page_state() and lock_page_memcg() deal with tail pages
correctly, namely by redirecting to the head page which has the
page->mem_cgroup set up.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-9-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: prepare move_account for removal of private page type counters

When memcg uses the generic vmstat counters, it doesn't need to do
anything at charging and uncharging time.  It does, however, need to
migrate counts when pages move to a different cgroup in move_account.

Prepare the move_account function for the arrival of NR_FILE_PAGES,
NR_ANON_MAPPED, NR_ANON_THPS etc.  by having a branch for files and a
branch for anon, which can then divided into sub-branches.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-8-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: prepare uncharging for removal of private page type counters

The uncharge batching code adds up the anon, file, kmem counts to
determine the total number of pages to uncharge and references to drop.
But the next patches will remove the anon and file counters.

Maintain an aggregate nr_pages in the uncharge_gather struct.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-7-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: convert page cache to a new mem_cgroup_charge() API

The try/commit/cancel protocol that memcg uses dates back to when pages
used to be uncharged upon removal from the page cache, and thus couldn't
be committed before the insertion had succeeded.  Nowadays, pages are
uncharged when they are physically freed; it doesn't matter whether the
insertion was successful or not.  For the page cache, the transaction
dance has become unnecessary.

Introduce a mem_cgroup_charge() function that simply charges a newly
allocated page to a cgroup and sets up page->mem_cgroup in one single
step.  If the insertion fails, the caller doesn't have to do anything but
free/put the page.

Then switch the page cache over to this new API.

Subsequent patches will also convert anon pages, but it needs a bit more
prep work.  Right now, memcg depends on page->mapping being already set up
at the time of charging, so that it can maintain its own MEMCG_CACHE and
MEMCG_RSS counters.  For anon, page->mapping is set under the same pte
lock under which the page is publishd, so a single charge point that can
block doesn't work there just yet.

The following prep patches will replace the private memcg counters with
the generic vmstat counters, thus removing the page->mapping dependency,
then complete the transition to the new single-point charge API and delete
the old transactional scheme.

v2: leave shmem swapcache when charging fails to avoid double IO (Joonsoo)
v3: rebase on preceeding shmem simplification patch

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-6-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: move out cgroup swaprate throttling

The cgroup swaprate throttling is about matching new anon allocations to
the rate of available IO when that is being throttled.  It's the io
controller hooking into the VM, rather than a memory controller thing.

Rename mem_cgroup_throttle_swaprate() to cgroup_throttle_swaprate(), and
drop the @memcg argument which is only used to check whether the preceding
page charge has succeeded and the fault is proceeding.

We could decouple the call from mem_cgroup_try_charge() here as well, but
that would cause unnecessary churn: the following patches convert all
callsites to a new charge API and we'll decouple as we go along.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-5-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: shmem: remove rare optimization when swapin races with hole punching

Commit 215c02bc33bb ("tmpfs: fix shmem_getpage_gfp() VM_BUG_ON")
recognized that hole punching can race with swapin and removed the
BUG_ON() for a truncated entry from the swapin path.

The patch also added a swapcache deletion to optimize this rare case:
Since swapin has the page locked, and free_swap_and_cache() merely
trylocks, this situation can leave the page stranded in swapcache.
Usually, page reclaim picks up stale swapcache pages, and the race can
happen at any other time when the page is locked.  (The same happens for
non-shmem swapin racing with page table zapping.) The thinking here was:
we already observed the race and we have the page locked, we may as well
do the cleanup instead of waiting for reclaim.

However, this optimization complicates the next patch which moves the
cgroup charging code around.  As this is just a minor speedup for a race
condition that is so rare that it required a fuzzer to trigger the
original BUG_ON(), it's no longer worth the complications.

Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200511181056.GA339505@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: drop @compound parameter from memcg charging API

The memcg charging API carries a boolean @compound parameter that tells
whether the page we're dealing with is a hugepage.
mem_cgroup_commit_charge() has another boolean @lrucare that indicates
whether the page needs LRU locking or not while charging.  The majority of
callsites know those parameters at compile time, which results in a lot of
naked "false, false" argument lists.  This makes for cryptic code and is a
breeding ground for subtle mistakes.

Thankfully, the huge page state can be inferred from the page itself and
doesn't need to be passed along.  This is safe because charging completes
before the page is published and somebody may split it.

Simplify the callsites by removing @compound, and let memcg infer the
state by using hpage_nr_pages() unconditionally.  That function does
PageTransHuge() to identify huge pages, which also helpfully asserts that
nobody passes in tail pages by accident.

The following patches will introduce a new charging API, best not to carry
over unnecessary weight.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-4-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: memcontrol: fix stat-corrupting race in charge moving

The move_lock is a per-memcg lock, but the VM accounting code that needs
to acquire it comes from the page and follows page->mem_cgroup under RCU
protection.  That means that the page becomes unlocked not when we drop
the move_lock, but when we update page->mem_cgroup.  And that assignment
doesn't imply any memory ordering.  If that pointer write gets reordered
against the reads of the page state - page_mapped, PageDirty etc.  the
state may change while we rely on it being stable and we can end up
corrupting the counters.

Place an SMP memory barrier to make sure we're done with all page state by
the time the new page->mem_cgroup becomes visible.

Also replace the open-coded move_lock with a lock_page_memcg() to make it
more obvious what we're serializing against.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-3-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: fix NUMA node file count error in replace_page_cache()

Patch series "mm: memcontrol: charge swapin pages on instantiation", v2.

This patch series reworks memcg to charge swapin pages directly at
swapin time, rather than at fault time, which may be much later, or
not happen at all.

Changes in version 2:
- prevent double charges on pre-allocated hugepages in khugepaged
- leave shmem swapcache when charging fails to avoid double IO (Joonsoo)
- fix temporary accounting bug by switching rmap<->commit (Joonsoo)
- fix double swap charge bug in cgroup1/cgroup2 code gating
- simplify swapin error checking (Joonsoo)
- mm: memcontrol: document the new swap control behavior (Alex)
- review tags

The delayed swapin charging scheme we have right now causes problems:

- Alex's per-cgroup lru_lock patches rely on pages that have been
  isolated from the LRU to have a stable page->mem_cgroup; otherwise
  the lock may change underneath him. Swapcache pages are charged only
  after they are added to the LRU, and charging doesn't follow the LRU
  isolation protocol.

- Joonsoo's anon workingset patches need a suitable LRU at the time
  the page enters the swap cache and displaces the non-resident
  info. But the correct LRU is only available after charging.

- It's a containment hole / DoS vector. Users can trigger arbitrarily
  large swap readahead using MADV_WILLNEED. The memory is never
  charged unless somebody actually touches it.

- It complicates the page->mem_cgroup stabilization rules

In order to charge pages directly at swapin time, the memcg code base
needs to be prepared, and several overdue cleanups become a necessity:

To charge pages at swapin time, we need to always have cgroup
ownership tracking of swap records. We also cannot rely on
page->mapping to tell apart page types at charge time, because that's
only set up during a page fault.

To eliminate the page->mapping dependency, memcg needs to ditch its
private page type counters (MEMCG_CACHE, MEMCG_RSS, NR_SHMEM) in favor
of the generic vmstat counters and accounting sites, such as
NR_FILE_PAGES, NR_ANON_MAPPED etc.

To switch to generic vmstat counters, the charge sequence must be
adjusted such that page->mem_cgroup is set up by the time these
counters are modified.

The series is structured as follows:

1. Bug fixes
2. Decoupling charging from rmap
3. Swap controller integration into memcg
4. Direct swapin charging

This patch (of 19):

When replacing one page with another one in the cache, we have to decrease
the file count of the old page's NUMA node and increase the one of the new
NUMA node, otherwise the old node leaks the count and the new node
eventually underflows its counter.

Fixes: 74d609585d8b ("page cache: Add and replace pages using the XArray")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-1-hannes@cmpxchg.org
Link: http://lkml.kernel.org/r/20200508183105.225460-2-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan: update the comment of should_continue_reclaim()

try_to_compact_zone() has been replaced by try_to_compact_pages(), which
is necessary to be updated in the comment of should_continue_reclaim().

Signed-off-by: Qiwu Chen <chenqiwu@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200501034907.22991-1-chenqiwu@xiaomi.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/vmscan.c: change prototype for shrink_page_list

commit 3c710c1ad11b ("mm, vmscan extract shrink_page_list reclaim counters
into a struct") changed data type for the function, so changing return
type for funciton and its caller.

Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/1588168259-25604-1-git-send-email-maninder1.s@samsung.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>