From: Greg KH <[email protected]> 3.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: David Rientjes <[email protected]> commit 4bf2bba3750f10aa9e62e6949bc7e8329990f01b upstream. If page migration cannot charge the temporary page to the memcg, migrate_pages() will return -ENOMEM. This isn't considered in memory compaction however, and the loop continues to iterate over all pageblocks trying to isolate and migrate pages. If a small number of very large memcgs happen to be oom, however, these attempts will mostly be futile leading to an enormous amout of cpu consumption due to the page migration failures. This patch will short circuit and fail memory compaction if migrate_pages() returns -ENOMEM. COMPACT_PARTIAL is returned in case some migrations were successful so that the page allocator will retry. Signed-off-by: David Rientjes <[email protected]> Acked-by: Mel Gorman <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Kamezawa Hiroyuki <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Andrea Arcangeli <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/compaction.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/mm/compaction.c +++ b/mm/compaction.c @@ -594,8 +594,11 @@ static int compact_zone(struct zone *zon if (err) { putback_lru_pages(&cc->migratepages); cc->nr_migratepages = 0; + if (err == -ENOMEM) { + ret = COMPACT_PARTIAL; + goto out; + } } - } out: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
