The patch titled
Subject: memory-failure: fix an error of mce_bad_pages statistics
has been added to the -mm tree. Its filename is
memory-failure-fix-an-error-of-mce_bad_pages-statistics.patch
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------------------------------------------------------
From: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Subject: memory-failure: fix an error of mce_bad_pages statistics
$ echo paddr > /sys/devices/system/memory/soft_offline_page to offline a
*free* page, the value of mce_bad_pages will be added, and the page is set
HWPoison flag, but it is still managed by page buddy alocator.
$ cat /proc/meminfo | grep HardwareCorrupted shows the value.
If we offline the same page, the value of mce_bad_pages will be added
*again*, this means the value is incorrect now. Assume the page is still
free during this short time.
soft_offline_page()
get_any_page()
"else if (is_free_buddy_page(p))" branch return 0
"goto done";
"atomic_long_add(1, &mce_bad_pages);"
This patch:
Move poisoned page check at the beginning of the function in order to
fix the error.
Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Tested-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 38 +++++++++++++++++---------------------
1 file changed, 17 insertions(+), 21 deletions(-)
diff -puN mm/memory-failure.c~memory-failure-fix-an-error-of-mce_bad_pages-statistics mm/memory-failure.c
--- a/mm/memory-failure.c~memory-failure-fix-an-error-of-mce_bad_pages-statistics
+++ a/mm/memory-failure.c
@@ -1419,18 +1419,17 @@ static int soft_offline_huge_page(struct
unsigned long pfn = page_to_pfn(page);
struct page *hpage = compound_head(page);
+ if (PageHWPoison(hpage)) {
+ pr_info("soft offline: %#lx hugepage already poisoned\n", pfn);
+ return -EBUSY;
+ }
+
ret = get_any_page(page, pfn, flags);
if (ret < 0)
return ret;
if (ret == 0)
goto done;
- if (PageHWPoison(hpage)) {
- put_page(hpage);
- pr_info("soft offline: %#lx hugepage already poisoned\n", pfn);
- return -EBUSY;
- }
-
/* Keep page count to indicate a given hugepage is isolated. */
ret = migrate_huge_page(hpage, new_page, MPOL_MF_MOVE_ALL, false,
MIGRATE_SYNC);
@@ -1441,12 +1440,11 @@ static int soft_offline_huge_page(struct
return ret;
}
done:
- if (!PageHWPoison(hpage))
- atomic_long_add(1 << compound_trans_order(hpage),
- &mce_bad_pages);
+ /* keep elevated page count for bad page */
+ atomic_long_add(1 << compound_trans_order(hpage), &mce_bad_pages);
set_page_hwpoison_huge_page(hpage);
dequeue_hwpoisoned_huge_page(hpage);
- /* keep elevated page count for bad page */
+
return ret;
}
@@ -1488,6 +1486,11 @@ int soft_offline_page(struct page *page,
}
}
+ if (PageHWPoison(page)) {
+ pr_info("soft offline: %#lx page already poisoned\n", pfn);
+ return -EBUSY;
+ }
+
ret = get_any_page(page, pfn, flags);
if (ret < 0)
return ret;
@@ -1519,19 +1522,11 @@ int soft_offline_page(struct page *page,
return -EIO;
}
- lock_page(page);
- wait_on_page_writeback(page);
-
/*
* Synchronized using the page lock with memory_failure()
*/
- if (PageHWPoison(page)) {
- unlock_page(page);
- put_page(page);
- pr_info("soft offline: %#lx page already poisoned\n", pfn);
- return -EBUSY;
- }
-
+ lock_page(page);
+ wait_on_page_writeback(page);
/*
* Try to invalidate first. This should work for
* non dirty unmapped page cache pages.
@@ -1583,8 +1578,9 @@ int soft_offline_page(struct page *page,
return ret;
done:
+ /* keep elevated page count for bad page */
atomic_long_add(1, &mce_bad_pages);
SetPageHWPoison(page);
- /* keep elevated page count for bad page */
+
return ret;
}
_
Patches currently in -mm which might be from qiuxishi@xxxxxxxxxx are
memory-failure-fix-an-error-of-mce_bad_pages-statistics.patch
memory-failure-do-code-refactor-of-soft_offline_page.patch
memory-failure-use-num_poisoned_pages-instead-of-mce_bad_pages.patch
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