From aff622495c9a0b56148192e53bdec539f5e147f2 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Wed, 21 Mar 2012 16:33:52 -0700 Subject: [PATCH] vmscan: only defer compaction for failed order and higher Currently a failed order-9 (transparent hugepage) compaction can lead to memory compaction being temporarily disabled for a memory zone. Even if we only need compaction for an order 2 allocation, eg. for jumbo frames networking. The fix is relatively straightforward: keep track of the highest order at which compaction is succeeding, and only defer compaction for orders at which compaction is failing. Signed-off-by: Rik van Riel Cc: Andrea Arcangeli Acked-by: Mel Gorman Cc: Johannes Weiner Cc: Minchan Kim Cc: KOSAKI Motohiro Cc: Hillf Danton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compaction.h | 14 ++++++++++---- include/linux/mmzone.h | 1 + mm/compaction.c | 12 +++++++++++- mm/page_alloc.c | 6 ++++-- mm/vmscan.c | 2 +- 5 files changed, 27 insertions(+), 8 deletions(-) diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 7a9323aef4a..51a90b7f2d6 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -34,20 +34,26 @@ extern unsigned long compaction_suitable(struct zone *zone, int order); * allocation success. 1 << compact_defer_limit compactions are skipped up * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT */ -static inline void defer_compaction(struct zone *zone) +static inline void defer_compaction(struct zone *zone, int order) { zone->compact_considered = 0; zone->compact_defer_shift++; + if (order < zone->compact_order_failed) + zone->compact_order_failed = order; + if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; } /* Returns true if compaction should be skipped this time */ -static inline bool compaction_deferred(struct zone *zone) +static inline bool compaction_deferred(struct zone *zone, int order) { unsigned long defer_limit = 1UL << zone->compact_defer_shift; + if (order < zone->compact_order_failed) + return false; + /* Avoid possible overflow */ if (++zone->compact_considered > defer_limit) zone->compact_considered = defer_limit; @@ -73,11 +79,11 @@ static inline unsigned long compaction_suitable(struct zone *zone, int order) return COMPACT_SKIPPED; } -static inline void defer_compaction(struct zone *zone) +static inline void defer_compaction(struct zone *zone, int order) { } -static inline bool compaction_deferred(struct zone *zone) +static inline bool compaction_deferred(struct zone *zone, int order) { return 1; } diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 650ba2fb330..dff71150966 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -365,6 +365,7 @@ struct zone { */ unsigned int compact_considered; unsigned int compact_defer_shift; + int compact_order_failed; #endif ZONE_PADDING(_pad1_) diff --git a/mm/compaction.c b/mm/compaction.c index 36f0f61f4a2..c4b344a9503 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -695,9 +695,19 @@ static int __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc) INIT_LIST_HEAD(&cc->freepages); INIT_LIST_HEAD(&cc->migratepages); - if (cc->order < 0 || !compaction_deferred(zone)) + if (cc->order < 0 || !compaction_deferred(zone, cc->order)) compact_zone(zone, cc); + if (cc->order > 0) { + int ok = zone_watermark_ok(zone, cc->order, + low_wmark_pages(zone), 0, 0); + if (ok && cc->order > zone->compact_order_failed) + zone->compact_order_failed = cc->order + 1; + /* Currently async compaction is never deferred. */ + else if (!ok && cc->sync) + defer_compaction(zone, cc->order); + } + VM_BUG_ON(!list_empty(&cc->freepages)); VM_BUG_ON(!list_empty(&cc->migratepages)); } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a13ded1938f..572b93ea475 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1990,7 +1990,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, if (!order) return NULL; - if (compaction_deferred(preferred_zone)) { + if (compaction_deferred(preferred_zone, order)) { *deferred_compaction = true; return NULL; } @@ -2012,6 +2012,8 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, if (page) { preferred_zone->compact_considered = 0; preferred_zone->compact_defer_shift = 0; + if (order >= preferred_zone->compact_order_failed) + preferred_zone->compact_order_failed = order + 1; count_vm_event(COMPACTSUCCESS); return page; } @@ -2028,7 +2030,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, * defer if the failure was a sync compaction failure. */ if (sync_migration) - defer_compaction(preferred_zone); + defer_compaction(preferred_zone, order); cond_resched(); } diff --git a/mm/vmscan.c b/mm/vmscan.c index b2b4c4a0ada..87e4d6a6dc1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2198,7 +2198,7 @@ static inline bool compaction_ready(struct zone *zone, struct scan_control *sc) * If compaction is deferred, reclaim up to a point where * compaction will have a chance of success when re-enabled */ - if (compaction_deferred(zone)) + if (compaction_deferred(zone, sc->order)) return watermark_ok; /* If compaction is not ready to start, keep reclaiming */ -- 2.20.1