On Wed, Jun 04, 2014 at 01:48:18PM +0800, Chen Yucong wrote:
> Until now, the kernel has the same policy to handle victimized page frames that
> belong to kernel-space(reserved/slab-subsystem) or non-LRU(unknown page state).
> In other word, the result of handling either of these victimized page frames is
> (IGNORED | FAILED), and the return value of memory_failure() is -EBUSY.
>
> This patch is to avoid that memory_failure() returns very soon due to the "true"
> value of (!PageLRU(p)), and it also ensures that action_result() can report more
> precise information("reserved kernel", "kernel slab", and "unknown page state")
> instead of "non LRU", especially for memory errors which are detected by memory-scrubbing.
>
> Changes since v1: http://www.spinics.net/lists/linux-mm/msg74044.html
> - Call goto just after if (hwpoison_filter(p)) block, and jump directly to just
> before the code determining the page_state, as suggested by Naoya Horiguchi.
>
> Signed-off-by: Chen Yucong <slaoub@xxxxxxxxx>
Looks good to me, thanks!
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> ---
> mm/memory-failure.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index e3154d9..1340b30 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -862,7 +862,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
> struct page *hpage = *hpagep;
> struct page *ppage;
>
> - if (PageReserved(p) || PageSlab(p))
> + if (PageReserved(p) || PageSlab(p) || !PageLRU(p))
> return SWAP_SUCCESS;
>
> /*
> @@ -1126,9 +1126,6 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
> action_result(pfn, "free buddy, 2nd try", DELAYED);
> return 0;
> }
> - action_result(pfn, "non LRU", IGNORED);
> - put_page(p);
> - return -EBUSY;
> }
> }
>
> @@ -1161,6 +1158,9 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
> return 0;
> }
>
> + if (!PageHuge(p) && !PageTransTail(p) && !PageLRU(p))
> + goto identify_page_state;
> +
> /*
> * For error on the tail page, we should set PG_hwpoison
> * on the head page to show that the hugepage is hwpoisoned
> @@ -1210,6 +1210,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
> goto out;
> }
>
> +identify_page_state:
> res = -EBUSY;
> /*
> * The first check uses the current page flags which may not have any
> --
> 1.7.10.4
>
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