Commit 7f354a54 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

mm, compaction: add vmstats for kcompactd work 

A "compact_daemon_wake" vmstat exists that represents the number of
times kcompactd has woken up.  This doesn't represent how much work it
actually did, though.

It's useful to understand how much compaction work is being done by
kcompactd versus other methods such as direct compaction and explicitly
triggered per-node (or system) compaction.

This adds two new vmstats: "compact_daemon_migrate_scanned" and
"compact_daemon_free_scanned" to represent the number of pages kcompactd
has scanned as part of its migration scanner and freeing scanner,
respectively.

These values are still accounted for in the general
"compact_migrate_scanned" and "compact_free_scanned" for compatibility.

It could be argued that explicitly triggered compaction could also be
tracked separately, and that could be added if others find it useful.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1612071749390.69852@chino.kir.corp.google.com


Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e57b9d8c

include/linux/vm_event_item.h

+1 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, 
		COMPACTISOLATED,

		COMPACTSTALL, COMPACTFAIL, COMPACTSUCCESS,

		KCOMPACTD_WAKE,

		KCOMPACTD_MIGRATE_SCANNED, KCOMPACTD_FREE_SCANNED,

#endif

#ifdef CONFIG_HUGETLB_PAGE

		HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,

mm/compaction.c

+19 −3
Original line number Diff line number Diff line
@@ -548,7 +548,7 @@ isolate_fail: 
	if (blockpfn == end_pfn)

		update_pageblock_skip(cc, valid_page, total_isolated, false);



	count_compact_events(COMPACTFREE_SCANNED, nr_scanned);

	cc->total_free_scanned += nr_scanned;

	if (total_isolated)

		count_compact_events(COMPACTISOLATED, total_isolated);

	return total_isolated;
@@ -931,7 +931,7 @@ isolate_fail: 
	trace_mm_compaction_isolate_migratepages(start_pfn, low_pfn,

						nr_scanned, nr_isolated);



	count_compact_events(COMPACTMIGRATE_SCANNED, nr_scanned);

	cc->total_migrate_scanned += nr_scanned;

	if (nr_isolated)

		count_compact_events(COMPACTISOLATED, nr_isolated);
@@ -1631,6 +1631,9 @@ out: 
			zone->compact_cached_free_pfn = free_pfn;

	}



	count_compact_events(COMPACTMIGRATE_SCANNED, cc->total_migrate_scanned);

	count_compact_events(COMPACTFREE_SCANNED, cc->total_free_scanned);



	trace_mm_compaction_end(start_pfn, cc->migrate_pfn,

				cc->free_pfn, end_pfn, sync, ret);
@@ -1645,6 +1648,8 @@ static enum compact_result compact_zone_order(struct zone *zone, int order, 
	struct compact_control cc = {

		.nr_freepages = 0,

		.nr_migratepages = 0,

		.total_migrate_scanned = 0,

		.total_free_scanned = 0,

		.order = order,

		.gfp_mask = gfp_mask,

		.zone = zone,
@@ -1757,6 +1762,8 @@ static void compact_node(int nid) 
	struct zone *zone;

	struct compact_control cc = {

		.order = -1,

		.total_migrate_scanned = 0,

		.total_free_scanned = 0,

		.mode = MIGRATE_SYNC,

		.ignore_skip_hint = true,

		.whole_zone = true,
@@ -1883,6 +1890,8 @@ static void kcompactd_do_work(pg_data_t *pgdat) 
	struct zone *zone;

	struct compact_control cc = {

		.order = pgdat->kcompactd_max_order,

		.total_migrate_scanned = 0,

		.total_free_scanned = 0,

		.classzone_idx = pgdat->kcompactd_classzone_idx,

		.mode = MIGRATE_SYNC_LIGHT,

		.ignore_skip_hint = true,
@@ -1891,7 +1900,7 @@ static void kcompactd_do_work(pg_data_t *pgdat) 
	};

	trace_mm_compaction_kcompactd_wake(pgdat->node_id, cc.order,

							cc.classzone_idx);

	count_vm_event(KCOMPACTD_WAKE);

	count_compact_event(KCOMPACTD_WAKE);



	for (zoneid = 0; zoneid <= cc.classzone_idx; zoneid++) {

		int status;
@@ -1909,6 +1918,8 @@ static void kcompactd_do_work(pg_data_t *pgdat) 


		cc.nr_freepages = 0;

		cc.nr_migratepages = 0;

		cc.total_migrate_scanned = 0;

		cc.total_free_scanned = 0;

		cc.zone = zone;

		INIT_LIST_HEAD(&cc.freepages);

		INIT_LIST_HEAD(&cc.migratepages);
@@ -1927,6 +1938,11 @@ static void kcompactd_do_work(pg_data_t *pgdat) 
			defer_compaction(zone, cc.order);

		}



		count_compact_events(KCOMPACTD_MIGRATE_SCANNED,

				     cc.total_migrate_scanned);

		count_compact_events(KCOMPACTD_FREE_SCANNED,

				     cc.total_free_scanned);



		VM_BUG_ON(!list_empty(&cc.freepages));

		VM_BUG_ON(!list_empty(&cc.migratepages));

	}

mm/internal.h

+2 −0
Original line number Diff line number Diff line
@@ -175,6 +175,8 @@ struct compact_control { 
	struct list_head migratepages;	/* List of pages being migrated */

	unsigned long nr_freepages;	/* Number of isolated free pages */

	unsigned long nr_migratepages;	/* Number of pages to migrate */

	unsigned long total_migrate_scanned;

	unsigned long total_free_scanned;

	unsigned long free_pfn;		/* isolate_freepages search base */

	unsigned long migrate_pfn;	/* isolate_migratepages search base */

	unsigned long last_migrated_pfn;/* Not yet flushed page being freed */

mm/vmstat.c

+2 −0
Original line number Diff line number Diff line
@@ -1038,6 +1038,8 @@ const char * const vmstat_text[] = { 
	"compact_fail",

	"compact_success",

	"compact_daemon_wake",

	"compact_daemon_migrate_scanned",

	"compact_daemon_free_scanned",

#endif



#ifdef CONFIG_HUGETLB_PAGE

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