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mm: compaction: abort compaction loop if lock is contended or run too long

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isolate_migratepages_range() might isolate no pages if for example when
zone->lru_lock is contended and running asynchronous compaction. In this
case, we should abort compaction, otherwise, compact_zone will run a
useless loop and make zone->lru_lock is even contended.

An additional check is added to ensure that cc.migratepages and
cc.freepages get properly drained whan compaction is aborted.

[minchan@kernel.org: Putback pages isolated for migration if aborting]
[akpm@linux-foundation.org: compact_zone_order requires non-NULL arg contended]
[akpm@linux-foundation.org: make compact_zone_order() require non-NULL arg `contended']
[minchan@kernel.org: Putback pages isolated for migration if aborting]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Shaohua Li 2012-10-08 16:32:27 -07:00 committed by Linus Torvalds
parent f2d52fe51c
commit e64c5237cf
2 changed files with 13 additions and 6 deletions
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17
mm/compaction.c
View file

@ -70,8 +70,7 @@ static bool compact_checklock_irqsave(spinlock_t *lock, unsigned long *flags,
/* async aborts if taking too long or contended */ /* async aborts if taking too long or contended */
if (!cc->sync) { if (!cc->sync) {
if (cc->contended) cc->contended = true;
*cc->contended = true;
return false; return false;
} }
@ -688,7 +687,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
/* Perform the isolation */ /* Perform the isolation */
low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn); low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn);
if (!low_pfn) if (!low_pfn || cc->contended)
return ISOLATE_ABORT; return ISOLATE_ABORT;
cc->migrate_pfn = low_pfn; cc->migrate_pfn = low_pfn;
@ -848,6 +847,8 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
switch (isolate_migratepages(zone, cc)) { switch (isolate_migratepages(zone, cc)) {
case ISOLATE_ABORT: case ISOLATE_ABORT:
ret = COMPACT_PARTIAL; ret = COMPACT_PARTIAL;
putback_lru_pages(&cc->migratepages);
cc->nr_migratepages = 0;
goto out; goto out;
case ISOLATE_NONE: case ISOLATE_NONE:
continue; continue;
@ -896,6 +897,7 @@ static unsigned long compact_zone_order(struct zone *zone,
bool sync, bool *contended, bool sync, bool *contended,
struct page **page) struct page **page)
{ {
unsigned long ret;
struct compact_control cc = { struct compact_control cc = {
.nr_freepages = 0, .nr_freepages = 0,
.nr_migratepages = 0, .nr_migratepages = 0,
@ -903,13 +905,18 @@ static unsigned long compact_zone_order(struct zone *zone,
.migratetype = allocflags_to_migratetype(gfp_mask), .migratetype = allocflags_to_migratetype(gfp_mask),
.zone = zone, .zone = zone,
.sync = sync, .sync = sync,
.contended = contended,
.page = page, .page = page,
}; };
INIT_LIST_HEAD(&cc.freepages); INIT_LIST_HEAD(&cc.freepages);
INIT_LIST_HEAD(&cc.migratepages); INIT_LIST_HEAD(&cc.migratepages);
return compact_zone(zone, &cc); ret = compact_zone(zone, &cc);
VM_BUG_ON(!list_empty(&cc.freepages));
VM_BUG_ON(!list_empty(&cc.migratepages));
*contended = cc.contended;
return ret;
} }
int sysctl_extfrag_threshold = 500; int sysctl_extfrag_threshold = 500;

2
mm/internal.h
View file

@ -130,7 +130,7 @@ struct compact_control {
int order; /* order a direct compactor needs */ int order; /* order a direct compactor needs */
int migratetype; /* MOVABLE, RECLAIMABLE etc */ int migratetype; /* MOVABLE, RECLAIMABLE etc */
struct zone *zone; struct zone *zone;
bool *contended; /* True if a lock was contended */ bool contended; /* True if a lock was contended */
struct page **page; /* Page captured of requested size */ struct page **page; /* Page captured of requested size */
}; };