mm,hwpoison,hugetlb,memory_hotplug: hotremove memory section with hwpoisoned hugepage

Patch series "mm, hwpoison: improve handling workload related to hugetlb
and memory_hotplug", v7.

This patchset tries to solve the issue among memory_hotplug, hugetlb and hwpoison.
In this patchset, memory hotplug handles hwpoison pages like below:

  - hwpoison pages should not prevent memory hotremove,
  - memory block with hwpoison pages should not be onlined.

This patch (of 4):

HWPoisoned page is not supposed to be accessed once marked, but currently
such accesses can happen during memory hotremove because
do_migrate_range() can be called before dissolve_free_huge_pages() is
called.

Clear HPageMigratable for hwpoisoned hugepages to prevent them from being
migrated.  This should be done in hugetlb_lock to avoid race against
isolate_hugetlb().

get_hwpoison_huge_page() needs to have a flag to show it's called from
unpoison to take refcount of hwpoisoned hugepages, so add it.

[naoya.horiguchi@linux.dev: remove TestClearHPageMigratable and reduce to test and clear separately]
Link: https://lkml.kernel.org/r/20221025053559.GA2104800@ik1-406-35019.vs.sakura.ne.jp
Link: https://lkml.kernel.org/r/20221024062012.1520887-1-naoya.horiguchi@linux.dev
Link: https://lkml.kernel.org/r/20221024062012.1520887-2-naoya.horiguchi@linux.dev
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 20a0d5a..65ea340 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -183,8 +183,9 @@ bool hugetlb_reserve_pages(struct inode *inode, long from, long to,
 long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
                                                long freed);
 int isolate_hugetlb(struct page *page, struct list_head *list);
-int get_hwpoison_huge_page(struct page *page, bool *hugetlb);
-int get_huge_page_for_hwpoison(unsigned long pfn, int flags);
+int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison);
+int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
+                               bool *migratable_cleared);
 void putback_active_hugepage(struct page *page);
 void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason);
 void free_huge_page(struct page *page);
@@ -391,12 +392,13 @@ static inline int isolate_hugetlb(struct page *page, struct list_head *list)
        return -EBUSY;
 }
 
-static inline int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
+static inline int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison)
 {
        return 0;
 }
 
-static inline int get_huge_page_for_hwpoison(unsigned long pfn, int flags)
+static inline int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
+                                       bool *migratable_cleared)
 {
        return 0;
 }

diff --git a/include/linux/mm.h b/include/linux/mm.h
index f6d2d2d..e2ac6ff 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3277,9 +3277,11 @@ extern void shake_page(struct page *p);
 extern atomic_long_t num_poisoned_pages __read_mostly;
 extern int soft_offline_page(unsigned long pfn, int flags);
 #ifdef CONFIG_MEMORY_FAILURE
-extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags);
+extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
+                                       bool *migratable_cleared);
 #else
-static inline int __get_huge_page_for_hwpoison(unsigned long pfn, int flags)
+static inline int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
+                                       bool *migratable_cleared)
 {
        return 0;
 }

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index fc8908d..fdb36af 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7265,7 +7265,7 @@ unlock:
        return ret;
 }
 
-int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
+int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison)
 {
        int ret = 0;
 
@@ -7275,7 +7275,7 @@ int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
                *hugetlb = true;
                if (HPageFreed(page))
                        ret = 0;
-               else if (HPageMigratable(page))
+               else if (HPageMigratable(page) || unpoison)
                        ret = get_page_unless_zero(page);
                else
                        ret = -EBUSY;
@@ -7284,12 +7284,13 @@ int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
        return ret;
 }
 
-int get_huge_page_for_hwpoison(unsigned long pfn, int flags)
+int get_huge_page_for_hwpoison(unsigned long pfn, int flags,
+                               bool *migratable_cleared)
 {
        int ret;
 
        spin_lock_irq(&hugetlb_lock);
-       ret = __get_huge_page_for_hwpoison(pfn, flags);
+       ret = __get_huge_page_for_hwpoison(pfn, flags, migratable_cleared);
        spin_unlock_irq(&hugetlb_lock);
        return ret;
 }

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 1359455..4fff0b3 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1244,7 +1244,7 @@ static int __get_hwpoison_page(struct page *page, unsigned long flags)
        int ret = 0;
        bool hugetlb = false;
 
-       ret = get_hwpoison_huge_page(head, &hugetlb);
+       ret = get_hwpoison_huge_page(head, &hugetlb, false);
        if (hugetlb)
                return ret;
 
@@ -1334,7 +1334,7 @@ static int __get_unpoison_page(struct page *page)
        int ret = 0;
        bool hugetlb = false;
 
-       ret = get_hwpoison_huge_page(head, &hugetlb);
+       ret = get_hwpoison_huge_page(head, &hugetlb, true);
        if (hugetlb)
                return ret;
 
@@ -1785,7 +1785,8 @@ void hugetlb_clear_page_hwpoison(struct page *hpage)
  *   -EBUSY        - the hugepage is busy (try to retry)
  *   -EHWPOISON    - the hugepage is already hwpoisoned
  */
-int __get_huge_page_for_hwpoison(unsigned long pfn, int flags)
+int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
+                                bool *migratable_cleared)
 {
        struct page *page = pfn_to_page(pfn);
        struct page *head = compound_head(page);
@@ -1815,6 +1816,15 @@ int __get_huge_page_for_hwpoison(unsigned long pfn, int flags)
                goto out;
        }
 
+       /*
+        * Clearing HPageMigratable for hwpoisoned hugepages to prevent them
+        * from being migrated by memory hotremove.
+        */
+       if (count_increased && HPageMigratable(head)) {
+               ClearHPageMigratable(head);
+               *migratable_cleared = true;
+       }
+
        return ret;
 out:
        if (count_increased)
@@ -1834,10 +1844,11 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb
        struct page *p = pfn_to_page(pfn);
        struct page *head;
        unsigned long page_flags;
+       bool migratable_cleared = false;
 
        *hugetlb = 1;
 retry:
-       res = get_huge_page_for_hwpoison(pfn, flags);
+       res = get_huge_page_for_hwpoison(pfn, flags, &migratable_cleared);
        if (res == 2) { /* fallback to normal page handling */
                *hugetlb = 0;
                return 0;
@@ -1861,6 +1872,8 @@ retry:
 
        if (hwpoison_filter(p)) {
                hugetlb_clear_page_hwpoison(head);
+               if (migratable_cleared)
+                       SetHPageMigratable(head);
                unlock_page(head);
                if (res == 1)
                        put_page(head);