2 bool "Extend memmap on extra space for more information on page"
4 Extend memmap on extra space for more information on page. This
5 could be used for debugging features that need to insert extra
6 field for every page. This extension enables us to save memory
7 by not allocating this extra memory according to boottime
10 config DEBUG_PAGEALLOC
11 bool "Debug page memory allocations"
12 depends on DEBUG_KERNEL
13 depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC
16 select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC
18 Unmap pages from the kernel linear mapping after free_pages().
19 Depending on runtime enablement, this results in a small or large
20 slowdown, but helps to find certain types of memory corruption.
22 For architectures which don't enable ARCH_SUPPORTS_DEBUG_PAGEALLOC,
23 fill the pages with poison patterns after free_pages() and verify
24 the patterns before alloc_pages(). Additionally,
25 this option cannot be enabled in combination with hibernation as
26 that would result in incorrect warnings of memory corruption after
27 a resume because free pages are not saved to the suspend image.
29 By default this option will have a small overhead, e.g. by not
30 allowing the kernel mapping to be backed by large pages on some
31 architectures. Even bigger overhead comes when the debugging is
32 enabled by DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc
33 command line parameter.
35 config DEBUG_PAGEALLOC_ENABLE_DEFAULT
36 bool "Enable debug page memory allocations by default?"
38 depends on DEBUG_PAGEALLOC
40 Enable debug page memory allocations by default? This value
41 can be overridden by debug_pagealloc=off|on.
43 config SLUB_DEBUG_PANIC_ON
44 bool "Enable to Panic on SLUB corruption detection"
47 SLUB has a resiliency feature enabled which restores bytes in
48 order for production environments to continue to operate. IN
49 debug options this may not be desirable as it prevents from
50 investigating the root cause which may be rooted within cache
54 bool "Poison pages after freeing"
56 select PAGE_POISONING_NO_SANITY if HIBERNATION
58 Fill the pages with poison patterns after free_pages() and verify
59 the patterns before alloc_pages. The filling of the memory helps
60 reduce the risk of information leaks from freed data. This does
61 have a potential performance impact.
63 Note that "poison" here is not the same thing as the "HWPoison"
64 for CONFIG_MEMORY_FAILURE. This is software poisoning only.
68 config PAGE_POISONING_ENABLE_DEFAULT
69 bool "Enable page poisoning by default?"
71 depends on PAGE_POISONING
73 Enable page poisoning of free pages by default? This value
74 can be overridden by page_poison=off|on. This can be used
75 to avoid passing the kernel parameter and let page poisoning
76 feature enabled by default.
78 config PAGE_POISONING_NO_SANITY
79 depends on PAGE_POISONING
80 bool "Only poison, don't sanity check"
82 Skip the sanity checking on alloc, only fill the pages with
83 poison on free. This reduces some of the overhead of the
86 If you are only interested in sanitization, say Y. Otherwise
89 config PAGE_POISONING_ZERO
90 bool "Use zero for poisoning instead of random data"
91 depends on PAGE_POISONING
93 Instead of using the existing poison value, fill the pages with
94 zeros. This makes it harder to detect when errors are occurring
95 due to sanitization but the zeroing at free means that it is
96 no longer necessary to write zeros when GFP_ZERO is used on
99 Enabling page poisoning with this option will disable hibernation