The patch titled Subject: mm: vmscan: check if reclaim should really abort even if compaction_ready() is true for one zone has been removed from the -mm tree. Its filename was mm-vmscan-check-if-reclaim-should-really-abort-even-if-compaction_ready-is-true-for-one-zone.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ From: Mel Gorman <mgorman@xxxxxxx> Subject: mm: vmscan: check if reclaim should really abort even if compaction_ready() is true for one zone If compaction can proceed for a given zone, shrink_zones() does not reclaim any more pages from it. After commit [e0c2327: vmscan: abort reclaim/compaction if compaction can proceed], do_try_to_free_pages() tries to finish as soon as possible once one zone can compact. This was intended to prevent slabs being shrunk unnecessarily but there are side-effects. One is that a small zone that is ready for compaction will abort reclaim even if the chances of successfully allocating a THP from that zone is small. It also means that reclaim can return too early even though sc->nr_to_reclaim pages were not reclaimed. This partially reverts the commit until it is proven that slabs are really being shrunk unnecessarily but preserves the check to return 1 to avoid OOM if reclaim was aborted prematurely. [aarcange@xxxxxxxxxx: This patch replaces a revert from Andrea] Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Reviewed-by: Rik van Riel <riel@xxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Minchan Kim <minchan.kim@xxxxxxxxx> Cc: Dave Jones <davej@xxxxxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Cc: Andy Isaacson <adi@xxxxxxxxxxxxx> Cc: Nai Xia <nai.xia@xxxxxxxxx> Cc: Johannes Weiner <jweiner@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmscan.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff -puN mm/vmscan.c~mm-vmscan-check-if-reclaim-should-really-abort-even-if-compaction_ready-is-true-for-one-zone mm/vmscan.c --- a/mm/vmscan.c~mm-vmscan-check-if-reclaim-should-really-abort-even-if-compaction_ready-is-true-for-one-zone +++ a/mm/vmscan.c @@ -2217,7 +2217,8 @@ static inline bool compaction_ready(stru * * This function returns true if a zone is being reclaimed for a costly * high-order allocation and compaction is ready to begin. This indicates to - * the caller that it should retry the allocation or fail. + * the caller that it should consider retrying the allocation instead of + * further reclaim. */ static bool shrink_zones(int priority, struct zonelist *zonelist, struct scan_control *sc) @@ -2226,7 +2227,7 @@ static bool shrink_zones(int priority, s struct zone *zone; unsigned long nr_soft_reclaimed; unsigned long nr_soft_scanned; - bool should_abort_reclaim = false; + bool aborted_reclaim = false; for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(sc->gfp_mask), sc->nodemask) { @@ -2252,7 +2253,7 @@ static bool shrink_zones(int priority, s * allocations. */ if (compaction_ready(zone, sc)) { - should_abort_reclaim = true; + aborted_reclaim = true; continue; } } @@ -2274,7 +2275,7 @@ static bool shrink_zones(int priority, s shrink_zone(priority, zone, sc); } - return should_abort_reclaim; + return aborted_reclaim; } static bool zone_reclaimable(struct zone *zone) @@ -2328,7 +2329,7 @@ static unsigned long do_try_to_free_page struct zoneref *z; struct zone *zone; unsigned long writeback_threshold; - bool should_abort_reclaim; + bool aborted_reclaim; get_mems_allowed(); delayacct_freepages_start(); @@ -2340,9 +2341,7 @@ static unsigned long do_try_to_free_page sc->nr_scanned = 0; if (!priority) disable_swap_token(sc->target_mem_cgroup); - should_abort_reclaim = shrink_zones(priority, zonelist, sc); - if (should_abort_reclaim) - break; + aborted_reclaim = shrink_zones(priority, zonelist, sc); /* * Don't shrink slabs when reclaiming memory from @@ -2409,8 +2408,8 @@ out: if (oom_killer_disabled) return 0; - /* Aborting reclaim to try compaction? don't OOM, then */ - if (should_abort_reclaim) + /* Aborted reclaim to try compaction? don't OOM, then */ + if (aborted_reclaim) return 1; /* top priority shrink_zones still had more to do? don't OOM, then */ _ Patches currently in -mm which might be from mgorman@xxxxxxx are origin.patch mm-fix-null-ptr-dereference-in-__count_immobile_pages.patch mm-__count_immobile_pages-make-sure-the-node-is-online.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html