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mm: compaction: abort compaction if too many pages are isolated and caller is asynchronous V2

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Asynchronous compaction is used when promoting to huge pages.  This is all
very nice but if there are a number of processes in compacting memory, a
large number of pages can be isolated.  An "asynchronous" process can
stall for long periods of time as a result with a user reporting that
firefox can stall for 10s of seconds.  This patch aborts asynchronous
compaction if too many pages are isolated as it's better to fail a
hugepage promotion than stall a process.

[minchan.kim@gmail.com: return COMPACT_PARTIAL for abort]
Reported-and-tested-by: Ury Stankevich <urykhy@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman 2011-06-15 15:08:52 -07:00 committed by Linus Torvalds
parent d179e84ba5
commit f9e35b3b41
1 changed files with 24 additions and 5 deletions
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29
mm/compaction.c
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@ -251,11 +251,18 @@ static bool too_many_isolated(struct zone *zone)
return isolated > (inactive + active) / 2;
}
/* possible outcome of isolate_migratepages */
typedef enum {
ISOLATE_ABORT, /* Abort compaction now */
ISOLATE_NONE, /* No pages isolated, continue scanning */
ISOLATE_SUCCESS, /* Pages isolated, migrate */
} isolate_migrate_t;
/*
* Isolate all pages that can be migrated from the block pointed to by
* the migrate scanner within compact_control.
*/
static unsigned long isolate_migratepages(struct zone *zone,
static isolate_migrate_t isolate_migratepages(struct zone *zone,
struct compact_control *cc)
{
unsigned long low_pfn, end_pfn;
@ -272,7 +279,7 @@ static unsigned long isolate_migratepages(struct zone *zone,
/* Do not cross the free scanner or scan within a memory hole */
if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {
cc->migrate_pfn = end_pfn;
return 0;
return ISOLATE_NONE;
}
/*
@ -281,10 +288,14 @@ static unsigned long isolate_migratepages(struct zone *zone,
* delay for some time until fewer pages are isolated
*/
while (unlikely(too_many_isolated(zone))) {
/* async migration should just abort */
if (!cc->sync)
return ISOLATE_ABORT;
congestion_wait(BLK_RW_ASYNC, HZ/10);
if (fatal_signal_pending(current))
return 0;
return ISOLATE_ABORT;
}
/* Time to isolate some pages for migration */
@ -369,7 +380,7 @@ static unsigned long isolate_migratepages(struct zone *zone,
trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
return cc->nr_migratepages;
return ISOLATE_SUCCESS;
}
/*
@ -535,8 +546,15 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
unsigned long nr_migrate, nr_remaining;
int err;
if (!isolate_migratepages(zone, cc))
switch (isolate_migratepages(zone, cc)) {
case ISOLATE_ABORT:
ret = COMPACT_PARTIAL;
goto out;
case ISOLATE_NONE:
continue;
case ISOLATE_SUCCESS:
;
}
nr_migrate = cc->nr_migratepages;
err = migrate_pages(&cc->migratepages, compaction_alloc,
@ -560,6 +578,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
}
out:
/* Release free pages and check accounting */
cc->nr_freepages -= release_freepages(&cc->freepages);
VM_BUG_ON(cc->nr_freepages != 0);