Re: [PATCH 3/4] mm: memory-failure: Fix isolated page count duringmemory failure

[Minchan Kim]

On Tue, Jun 07, 2011 at 04:07:04PM +0100, Mel Gorman wrote:
> From: Minchan Kim <minchan.kim@xxxxxxxxx>
> 
> From: Minchan Kim <minchan.kim@xxxxxxxxx>
> 
> Pages isolated for migration are accounted with the vmstat counters
> NR_ISOLATE_[ANON|FILE]. Callers of migrate_pages() are expected to
> increment these counters when pages are isolated from the LRU. Once
> the pages have been migrated, they are put back on the LRU or freed
> and the isolated count is decremented.
> 
> Memory failure is not properly accounting for pages it isolates
> causing the NR_ISOLATED counters to be negative. On SMP builds,
> this goes unnoticed as negative counters are treated as 0 due to
> expected per-cpu drift. On UP builds, the counter is treated by
> too_many_isolated() as a large value causing processes to enter D
> state during page reclaim or compaction. This patch accounts for
> pages isolated by memory failure correctly.
> 
> [mgorman@xxxxxxx: Updated changelog]
> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
> Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>

I was about to resend this patch with your updated description.
Thanks! Mel.

-- 
Kind regards
Minchan Kim
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