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SubjectRe: [PATCH 3/4] mm: memory-failure: Fix isolated page count during memory failure
On Tue 07-06-11 16:07:04, Mel Gorman wrote:
> From: Minchan Kim <>
> From: Minchan Kim <>
> 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.

Aren't we missing this in compact_zone as well? AFAICS there is no
accounting done after we isolate pages from LRU? Or am I missing

> 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.
> [ Updated changelog]
> Signed-off-by: Minchan Kim <>
> Signed-off-by: Mel Gorman <>
> Reviewed-by: Andrea Arcangeli <>

Reviewed-by: Michal Hocko <>

Michal Hocko
Lihovarska 1060/12
190 00 Praha 9
Czech Republic

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