CMA: migrate mlocked pages

Presently CMA cannot migrate mlocked pages so it ends up failing to allocate
contiguous memory space.

This patch makes mlocked pages be migrated out.  Of course, it can affect
realtime processes but in CMA usecase, contiguous memory allocation failing
is far worse than access latency to an mlocked page being variable while
CMA is running.  If someone wants to make the system realtime, he shouldn't
enable CMA because stalls can still happen at random times.

[akpm@linux-foundation.org: tweak comment text, per Mel]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Minchan Kim
2012-10-08 16:33:48 -07:00
committed by Linus Torvalds
parent 7a71932d56
commit e46a28790e
5 changed files with 12 additions and 6 deletions

View File

@ -5690,7 +5690,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
if (list_empty(&cc->migratepages)) {
cc->nr_migratepages = 0;
pfn = isolate_migratepages_range(cc->zone, cc,
pfn, end);
pfn, end, true);
if (!pfn) {
ret = -EINTR;
break;