The patch titled
Subject: mm/hwpoison: disable pcp for page_handle_poison()
has been added to the -mm tree. Its filename is
mm-hwpoison-disable-pcp-for-page_handle_poison.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-hwpoison-disable-pcp-for-page_handle_poison.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-hwpoison-disable-pcp-for-page_handle_poison.patch
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------------------------------------------------------
From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Subject: mm/hwpoison: disable pcp for page_handle_poison()
Recent changes by patch "mm/page_alloc: allow high-order pages to be
stored on the per-cpu lists" makes kernels determine whether to use pcp by
pcp_allowed_order(), which breaks soft-offline for hugetlb pages.
Soft-offline dissolves a migration source page, then removes it from buddy
free list, so it's assumed that any subpage of the soft-offlined hugepage
are recognized as a buddy page just after returning from
dissolve_free_huge_page(). pcp_allowed_order() returns true for hugetlb,
so this assumption is no longer true.
So disable pcp during dissolve_free_huge_page() and take_page_off_buddy()
to prevent soft-offlined hugepages from linking to pcp lists.
Soft-offline should not be common events so the impact on performance
should be minimal. And I think that the optimization of Mel's patch could
benefit to hugetlb so zone_pcp_disable() is called only in hwpoison
context.
Link: https://lkml.kernel.org/r/20210617092626.291006-1-nao.horiguchi@xxxxxxxxx
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
--- a/mm/memory-failure.c~mm-hwpoison-disable-pcp-for-page_handle_poison
+++ a/mm/memory-failure.c
@@ -65,6 +65,19 @@ int sysctl_memory_failure_recovery __rea
atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0);
+static bool __page_handle_poison(struct page *page)
+{
+ bool ret;
+
+ zone_pcp_disable(page_zone(page));
+ ret = dissolve_free_huge_page(page);
+ if (!ret)
+ ret = take_page_off_buddy(page);
+ zone_pcp_enable(page_zone(page));
+
+ return ret;
+}
+
static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release)
{
if (hugepage_or_freepage) {
@@ -72,7 +85,7 @@ static bool page_handle_poison(struct pa
* Doing this check for free pages is also fine since dissolve_free_huge_page
* returns 0 for non-hugetlb pages as well.
*/
- if (dissolve_free_huge_page(page) || !take_page_off_buddy(page))
+ if (!__page_handle_poison(page))
/*
* We could fail to take off the target page from buddy
* for example due to racy page allocation, but that's
@@ -842,7 +855,7 @@ static int me_huge_page(struct page *p,
*/
if (PageAnon(hpage))
put_page(hpage);
- if (!dissolve_free_huge_page(p) && take_page_off_buddy(p)) {
+ if (__page_handle_poison(p)) {
page_ref_inc(p);
res = MF_RECOVERED;
}
@@ -1287,7 +1300,7 @@ static int memory_failure_hugetlb(unsign
}
unlock_page(head);
res = MF_FAILED;
- if (!dissolve_free_huge_page(p) && take_page_off_buddy(p)) {
+ if (__page_handle_poison(p)) {
page_ref_inc(p);
res = MF_RECOVERED;
}
_
Patches currently in -mm which might be from naoya.horiguchi@xxxxxxx are
mm-hwpoison-do-not-lock-page-again-when-me_huge_page-successfully-recovers.patch
mm-hwpoison-disable-pcp-for-page_handle_poison.patch
mmhwpoison-send-sigbus-with-error-virutal-address.patch
mmhwpoison-send-sigbus-with-error-virutal-address-fix.patch
mmhwpoison-make-get_hwpoison_page-call-get_any_page.patch
