On 01/16/2015 06:47 AM, Andrew Morton wrote:
From: Andrew Morton <a...@linux-foundation.org> Subject: mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated-fixMove the zone_page_state_snapshot() fallback logic into too_many_isolated(), so shrink_inactive_list() doesn't incorrectly call congestion_wait(). Cc: Johannes Weiner <han...@cmpxchg.org> Cc: Mel Gorman <mgor...@suse.de> Cc: Michal Hocko <mho...@suse.cz> Cc: Minchan Kim <minc...@kernel.org> Cc: Vinayak Menon <vinme...@codeaurora.org> Cc: Vladimir Davydov <vdavy...@parallels.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> --- mm/vmscan.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) diff -puN mm/vmscan.c~mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated-fix mm/vmscan.c --- a/mm/vmscan.c~mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated-fix +++ a/mm/vmscan.c @@ -1402,7 +1402,7 @@ int isolate_lru_page(struct page *page) } static int __too_many_isolated(struct zone *zone, int file, - struct scan_control *sc, int safe) + struct scan_control *sc, int safe) { unsigned long inactive, isolated; @@ -1435,7 +1435,7 @@ static int __too_many_isolated(struct zo * unnecessary swapping, thrashing and OOM. */ static int too_many_isolated(struct zone *zone, int file, - struct scan_control *sc, int safe) + struct scan_control *sc) { if (current_is_kswapd()) return 0; @@ -1443,12 +1443,14 @@ static int too_many_isolated(struct zone if (!global_reclaim(sc)) return 0; - if (unlikely(__too_many_isolated(zone, file, sc, 0))) { - if (safe) - return __too_many_isolated(zone, file, sc, safe); - else - return 1; - } + /* + * __too_many_isolated(safe=0) is fast but inaccurate, because it + * doesn't account for the vm_stat_diff[] counters. So if it looks + * like too_many_isolated() is about to return true, fall back to the + * slower, more accurate zone_page_state_snapshot(). + */ + if (unlikely(__too_many_isolated(zone, file, sc, 0))) + return __too_many_isolated(zone, file, sc, safe);
Just noticed now that, in the above statement it should be "1", instead of "safe". "safe" is not declared.
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