lkml.org 
[lkml]   [2012]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] MCE: fix an error of mce_bad_pages statistics
On x86 platform, if we use "/sys/devices/system/memory/soft_offline_page" to offline a
free page twice, the value of mce_bad_pages will be added twice. So this is an error,
since the page was already marked HWPoison, we should skip the page and don't add the
value of mce_bad_pages.

$ cat /proc/meminfo | grep HardwareCorrupted

soft_offline_page()
get_any_page()
atomic_long_add(1, &mce_bad_pages)

The free page which marked HWPoison is still managed by page buddy allocator. So when
offlining it again, get_any_page() always returns 0 with
"pr_info("%s: %#lx free buddy page\n", __func__, pfn);".

When page is allocated, the PageBuddy is removed in bad_page(), then get_any_page()
returns -EIO with pr_info("%s: %#lx: unknown zero refcount page type %lx\n", so
mce_bad_pages will not be added.

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
---
mm/memory-failure.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 8b20278..02a522e 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1375,6 +1375,11 @@ static int get_any_page(struct page *p, unsigned long pfn, int flags)
if (flags & MF_COUNT_INCREASED)
return 1;

+ if (PageHWPoison(p)) {
+ pr_info("%s: %#lx page already poisoned\n", __func__, pfn);
+ return -EBUSY;
+ }
+
/*
* The lock_memory_hotplug prevents a race with memory hotplug.
* This is a big hammer, a better would be nicer.
--
1.7.6.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2012-12-07 04:21    [W:0.040 / U:1.848 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site