[RFC v9 PATCH 20/21] memory-hotplug: clear hwpoisoned flag when onlining pages

[andywu106建国]

2012/9/5 <wency at cn.fujitsu.com>
>
> From: Wen Congyang <wency at cn.fujitsu.com>
>
> hwpoisoned may set when we offline a page by the sysfs interface
> /sys/devices/system/memory/soft_offline_page or
> /sys/devices/system/memory/hard_offline_page. If we don't clear
> this flag when onlining pages, this page can't be freed, and will
> not in free list. So we can't offline these pages again. So we
> should clear this flag when onlining pages.
>
> CC: David Rientjes <rientjes at google.com>
> CC: Jiang Liu <liuj97 at gmail.com>
> CC: Len Brown <len.brown at intel.com>
> CC: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> CC: Paul Mackerras <paulus at samba.org>
> CC: Christoph Lameter <cl at linux.com>
> Cc: Minchan Kim <minchan.kim at gmail.com>
> CC: Andrew Morton <akpm at linux-foundation.org>
> CC: KOSAKI Motohiro <kosaki.motohiro at jp.fujitsu.com>
> CC: Yasuaki Ishimatsu <isimatu.yasuaki at jp.fujitsu.com>
> Signed-off-by: Wen Congyang <wency at cn.fujitsu.com>
> ---
>  mm/memory_hotplug.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 270c249..140c080 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -661,6 +661,11 @@ EXPORT_SYMBOL_GPL(__online_page_increment_counters);
>
>  void __online_page_free(struct page *page)
>  {
> +#ifdef CONFIG_MEMORY_FAILURE
> +       /* The page may be marked HWPoisoned by soft/hard offline page */
> +       ClearPageHWPoison(page);

Hi Congyang,
I think you should decrease mce_bad_pages counter her
atomic_long_sub(1, &mce_bad_pages);

>
> +#endif
> +
>         ClearPageReserved(page);
>         init_page_count(page);
>         __free_page(page);
> --
> 1.7.1
>
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