On Fri, Dec 07, 2012 at 04:48:45PM +0800, Xishi Qiu wrote:
> 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)
>
> Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
> ---
> mm/memory-failure.c | 7 +++++--
> 1 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 8b20278..de760ca 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1582,8 +1582,11 @@ int soft_offline_page(struct page *page, int flags)
> return ret;
>
> done:
> - atomic_long_add(1, &mce_bad_pages);
> - SetPageHWPoison(page);
> /* keep elevated page count for bad page */
> + if (!PageHWPoison(page)) {
> + atomic_long_add(1, &mce_bad_pages);
> + SetPageHWPoison(page);
> + }
Ok, I don't know the memory-failure code all that well but IMHO why
should we wade through the whole soft_offline_page function for a page
which has been marked as poisoned already?
IOW, why not do what you started with previously and exit this function
ASAP:
---
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 8b20278be6a6..a83baeca0644 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1494,6 +1494,12 @@ int soft_offline_page(struct page *page, int flags)
if (ret == 0)
goto done;
+ if (PageHWPoison(page)) {
+ put_page(page);
+ pr_info("soft offline: %#lx page already poisoned\n", pfn);
+ return -EBUSY;
+ }
+
/*
* Page cache page we can handle?
*/
---
--
Regards/Gruss,
Boris.
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