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memory-failure: fix an error of mce_bad_pages statistics 

When doing

    $ 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@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Tested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Xishi Qiu 2013-02-22 16:33:59 -08:00 committed by Linus Torvalds
parent 194159fbcc
commit 0ebff32c36
1 changed files with 17 additions and 21 deletions
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38
mm/memory-failure.c
View File

@ -1419,18 +1419,17 @@ static int soft_offline_huge_page(struct page *page, int flags)
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 page *page, int flags)
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, int flags)
}
}
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, int flags)
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, int flags)
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;
}