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	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 <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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					 3 changed files with 54 additions and 18 deletions
				
			
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			@ -11,6 +11,9 @@
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/* The full zone was compacted */
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#define COMPACT_COMPLETE	3
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#define COMPACT_MODE_DIRECT_RECLAIM	0
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#define COMPACT_MODE_KSWAPD		1
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#ifdef CONFIG_COMPACTION
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extern int sysctl_compact_memory;
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extern int sysctl_compaction_handler(struct ctl_table *table, int write,
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			@ -25,7 +28,8 @@ extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
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			bool sync);
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extern unsigned long compaction_suitable(struct zone *zone, int order);
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extern unsigned long compact_zone_order(struct zone *zone, int order,
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						gfp_t gfp_mask, bool sync);
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					gfp_t gfp_mask, bool sync,
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					int compact_mode);
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/* Do not skip compaction more than 64 times */
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#define COMPACT_MAX_DEFER_SHIFT 6
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			@ -70,9 +74,10 @@ static inline unsigned long compaction_suitable(struct zone *zone, int order)
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}
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static inline unsigned long compact_zone_order(struct zone *zone, int order,
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						gfp_t gfp_mask, bool sync)
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					       gfp_t gfp_mask, bool sync,
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					       int compact_mode)
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{
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	return 0;
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	return COMPACT_CONTINUE;
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}
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static inline void defer_compaction(struct zone *zone)
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			@ -42,6 +42,8 @@ struct compact_control {
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	unsigned int order;		/* order a direct compactor needs */
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	int migratetype;		/* MOVABLE, RECLAIMABLE etc */
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	struct zone *zone;
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	int compact_mode;
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};
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static unsigned long release_freepages(struct list_head *freelist)
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			@ -382,10 +384,10 @@ static void update_nr_listpages(struct compact_control *cc)
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}
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static int compact_finished(struct zone *zone,
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						struct compact_control *cc)
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			    struct compact_control *cc)
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{
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	unsigned int order;
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	unsigned long watermark = low_wmark_pages(zone) + (1 << cc->order);
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	unsigned long watermark;
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	if (fatal_signal_pending(current))
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		return COMPACT_PARTIAL;
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			@ -395,12 +397,27 @@ static int compact_finished(struct zone *zone,
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		return COMPACT_COMPLETE;
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	/* Compaction run is not finished if the watermark is not met */
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	if (cc->compact_mode != COMPACT_MODE_KSWAPD)
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		watermark = low_wmark_pages(zone);
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	else
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		watermark = high_wmark_pages(zone);
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	watermark += (1 << cc->order);
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	if (!zone_watermark_ok(zone, cc->order, watermark, 0, 0))
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		return COMPACT_CONTINUE;
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	if (cc->order == -1)
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		return COMPACT_CONTINUE;
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	/*
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	 * Generating only one page of the right order is not enough
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	 * for kswapd, we must continue until we're above the high
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	 * watermark as a pool for high order GFP_ATOMIC allocations
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	 * too.
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	 */
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	if (cc->compact_mode == COMPACT_MODE_KSWAPD)
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		return COMPACT_CONTINUE;
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	/* Direct compactor: Is a suitable page free? */
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	for (order = cc->order; order < MAX_ORDER; order++) {
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		/* Job done if page is free of the right migratetype */
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			@ -514,8 +531,9 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
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}
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unsigned long compact_zone_order(struct zone *zone,
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						int order, gfp_t gfp_mask,
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						bool sync)
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				 int order, gfp_t gfp_mask,
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				 bool sync,
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				 int compact_mode)
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{
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	struct compact_control cc = {
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		.nr_freepages = 0,
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			@ -524,6 +542,7 @@ unsigned long compact_zone_order(struct zone *zone,
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		.migratetype = allocflags_to_migratetype(gfp_mask),
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		.zone = zone,
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		.sync = sync,
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		.compact_mode = compact_mode,
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	};
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	INIT_LIST_HEAD(&cc.freepages);
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	INIT_LIST_HEAD(&cc.migratepages);
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			@ -569,7 +588,8 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist,
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								nodemask) {
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		int status;
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		status = compact_zone_order(zone, order, gfp_mask, sync);
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		status = compact_zone_order(zone, order, gfp_mask, sync,
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					    COMPACT_MODE_DIRECT_RECLAIM);
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		rc = max(status, rc);
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		/* If a normal allocation would succeed, stop compacting */
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			@ -600,6 +620,7 @@ static int compact_node(int nid)
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			.nr_freepages = 0,
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			.nr_migratepages = 0,
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			.order = -1,
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			.compact_mode = COMPACT_MODE_DIRECT_RECLAIM,
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		};
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		zone = &pgdat->node_zones[zoneid];
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										30
									
								
								mm/vmscan.c
									
									
									
									
									
								
							
							
						
						
									
										30
									
								
								mm/vmscan.c
									
									
									
									
									
								
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			@ -41,6 +41,7 @@
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#include <linux/memcontrol.h>
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#include <linux/delayacct.h>
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#include <linux/sysctl.h>
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#include <linux/compaction.h>
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#include <asm/tlbflush.h>
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#include <asm/div64.h>
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			@ -2382,6 +2383,7 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
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		 * cause too much scanning of the lower zones.
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		 */
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		for (i = 0; i <= end_zone; i++) {
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			int compaction;
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			struct zone *zone = pgdat->node_zones + i;
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			int nr_slab;
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			@ -2411,9 +2413,26 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
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						lru_pages);
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			sc.nr_reclaimed += reclaim_state->reclaimed_slab;
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			total_scanned += sc.nr_scanned;
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			compaction = 0;
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			if (order &&
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			    zone_watermark_ok(zone, 0,
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					       high_wmark_pages(zone),
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					      end_zone, 0) &&
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			    !zone_watermark_ok(zone, order,
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					       high_wmark_pages(zone),
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					       end_zone, 0)) {
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				compact_zone_order(zone,
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						   order,
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						   sc.gfp_mask, false,
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						   COMPACT_MODE_KSWAPD);
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				compaction = 1;
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			}
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			if (zone->all_unreclaimable)
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				continue;
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			if (nr_slab == 0 && !zone_reclaimable(zone))
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			if (!compaction && nr_slab == 0 &&
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			    !zone_reclaimable(zone))
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				zone->all_unreclaimable = 1;
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			/*
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			 * If we've done a decent amount of scanning and
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			@ -2424,15 +2443,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
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			    total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2)
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				sc.may_writepage = 1;
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			/*
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			 * Compact the zone for higher orders to reduce
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			 * latencies for higher-order allocations that
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			 * would ordinarily call try_to_compact_pages()
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			 */
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			if (sc.order > PAGE_ALLOC_COSTLY_ORDER)
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				compact_zone_order(zone, sc.order, sc.gfp_mask,
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							false);
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			if (!zone_watermark_ok_safe(zone, order,
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					high_wmark_pages(zone), end_zone, 0)) {
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				all_zones_ok = 0;
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