From 5a03b051ed87e72b959f32a86054e1142ac4cf55 Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli Date: Thu, 13 Jan 2011 15:47:11 -0800 Subject: [PATCH] thp: use compaction in kswapd for GFP_ATOMIC order > 0 This takes advantage of memory compaction to properly generate pages of order > 0 if regular page reclaim fails and priority level becomes more severe and we don't reach the proper watermarks. Signed-off-by: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/compaction.h | 11 ++++++++--- mm/compaction.c | 31 ++++++++++++++++++++++++++----- mm/vmscan.c | 30 ++++++++++++++++++++---------- 3 files changed, 54 insertions(+), 18 deletions(-) diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 72cba4034785..dfa2ed4c0d26 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -11,6 +11,9 @@ /* The full zone was compacted */ #define COMPACT_COMPLETE 3 +#define COMPACT_MODE_DIRECT_RECLAIM 0 +#define COMPACT_MODE_KSWAPD 1 + #ifdef CONFIG_COMPACTION extern int sysctl_compact_memory; extern int sysctl_compaction_handler(struct ctl_table *table, int write, @@ -25,7 +28,8 @@ extern unsigned long try_to_compact_pages(struct zonelist *zonelist, bool sync); extern unsigned long compaction_suitable(struct zone *zone, int order); extern unsigned long compact_zone_order(struct zone *zone, int order, - gfp_t gfp_mask, bool sync); + gfp_t gfp_mask, bool sync, + int compact_mode); /* Do not skip compaction more than 64 times */ #define COMPACT_MAX_DEFER_SHIFT 6 @@ -70,9 +74,10 @@ static inline unsigned long compaction_suitable(struct zone *zone, int order) } static inline unsigned long compact_zone_order(struct zone *zone, int order, - gfp_t gfp_mask, bool sync) + gfp_t gfp_mask, bool sync, + int compact_mode) { - return 0; + return COMPACT_CONTINUE; } static inline void defer_compaction(struct zone *zone) diff --git a/mm/compaction.c b/mm/compaction.c index da25b5a2e476..60d52a7298d5 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -42,6 +42,8 @@ struct compact_control { unsigned int order; /* order a direct compactor needs */ int migratetype; /* MOVABLE, RECLAIMABLE etc */ struct zone *zone; + + int compact_mode; }; static unsigned long release_freepages(struct list_head *freelist) @@ -382,10 +384,10 @@ static void update_nr_listpages(struct compact_control *cc) } static int compact_finished(struct zone *zone, - struct compact_control *cc) + struct compact_control *cc) { unsigned int order; - unsigned long watermark = low_wmark_pages(zone) + (1 << cc->order); + unsigned long watermark; if (fatal_signal_pending(current)) return COMPACT_PARTIAL; @@ -395,12 +397,27 @@ static int compact_finished(struct zone *zone, return COMPACT_COMPLETE; /* Compaction run is not finished if the watermark is not met */ + if (cc->compact_mode != COMPACT_MODE_KSWAPD) + watermark = low_wmark_pages(zone); + else + watermark = high_wmark_pages(zone); + watermark += (1 << cc->order); + if (!zone_watermark_ok(zone, cc->order, watermark, 0, 0)) return COMPACT_CONTINUE; if (cc->order == -1) return COMPACT_CONTINUE; + /* + * Generating only one page of the right order is not enough + * for kswapd, we must continue until we're above the high + * watermark as a pool for high order GFP_ATOMIC allocations + * too. + */ + if (cc->compact_mode == COMPACT_MODE_KSWAPD) + return COMPACT_CONTINUE; + /* Direct compactor: Is a suitable page free? */ for (order = cc->order; order < MAX_ORDER; order++) { /* Job done if page is free of the right migratetype */ @@ -514,8 +531,9 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) } unsigned long compact_zone_order(struct zone *zone, - int order, gfp_t gfp_mask, - bool sync) + int order, gfp_t gfp_mask, + bool sync, + int compact_mode) { struct compact_control cc = { .nr_freepages = 0, @@ -524,6 +542,7 @@ unsigned long compact_zone_order(struct zone *zone, .migratetype = allocflags_to_migratetype(gfp_mask), .zone = zone, .sync = sync, + .compact_mode = compact_mode, }; INIT_LIST_HEAD(&cc.freepages); INIT_LIST_HEAD(&cc.migratepages); @@ -569,7 +588,8 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist, nodemask) { int status; - status = compact_zone_order(zone, order, gfp_mask, sync); + status = compact_zone_order(zone, order, gfp_mask, sync, + COMPACT_MODE_DIRECT_RECLAIM); rc = max(status, rc); /* If a normal allocation would succeed, stop compacting */ @@ -600,6 +620,7 @@ static int compact_node(int nid) .nr_freepages = 0, .nr_migratepages = 0, .order = -1, + .compact_mode = COMPACT_MODE_DIRECT_RECLAIM, }; zone = &pgdat->node_zones[zoneid]; diff --git a/mm/vmscan.c b/mm/vmscan.c index cfdef0bcc7ab..f5b762ae23a2 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include @@ -2382,6 +2383,7 @@ loop_again: * cause too much scanning of the lower zones. */ for (i = 0; i <= end_zone; i++) { + int compaction; struct zone *zone = pgdat->node_zones + i; int nr_slab; @@ -2411,9 +2413,26 @@ loop_again: lru_pages); sc.nr_reclaimed += reclaim_state->reclaimed_slab; total_scanned += sc.nr_scanned; + + compaction = 0; + if (order && + zone_watermark_ok(zone, 0, + high_wmark_pages(zone), + end_zone, 0) && + !zone_watermark_ok(zone, order, + high_wmark_pages(zone), + end_zone, 0)) { + compact_zone_order(zone, + order, + sc.gfp_mask, false, + COMPACT_MODE_KSWAPD); + compaction = 1; + } + if (zone->all_unreclaimable) continue; - if (nr_slab == 0 && !zone_reclaimable(zone)) + if (!compaction && nr_slab == 0 && + !zone_reclaimable(zone)) zone->all_unreclaimable = 1; /* * If we've done a decent amount of scanning and @@ -2424,15 +2443,6 @@ loop_again: total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2) sc.may_writepage = 1; - /* - * Compact the zone for higher orders to reduce - * latencies for higher-order allocations that - * would ordinarily call try_to_compact_pages() - */ - if (sc.order > PAGE_ALLOC_COSTLY_ORDER) - compact_zone_order(zone, sc.order, sc.gfp_mask, - false); - if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone), end_zone, 0)) { all_zones_ok = 0;