Messages in this thread | | | From | Minchan Kim <> | Subject | Re: [patch] mm, thp: abort compaction if migration page cannot be charged to memcg | Date | Thu, 21 Jun 2012 17:11:40 +0900 |
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On 06/21/2012 03:52 PM, David Rientjes wrote:
> If page migration cannot charge the new 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 in a futile attempt to continue migrations which are only bound to > fail.
Hmm, it might be dumb question. I imagine that pages in next pageblock could be in another memcg so it could be successful. Why should we stop compaction once it fails to migrate pages in current pageblock/memcg?
> > This 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 <rientjes@google.com> > --- > mm/compaction.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/compaction.c b/mm/compaction.c > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -701,8 +701,11 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) > if (err) { > putback_lru_pages(&cc->migratepages); > cc->nr_migratepages = 0; > + if (err == -ENOMEM) { > + ret = COMPACT_PARTIAL; > + goto out; > + } > } > - > } > > out:
-- Kind regards, Minchan Kim
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