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>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index c6e4dd3..1a9242c 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1419,18 +1419,17 @@
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 @@
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 @@
}
}
+ 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 @@
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 @@
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;
}