On Sun 19-10-14 11:30:47, Johannes Weiner wrote: > Better explain re-entrant migration when compaction races with > reclaim, and also mention swapcache readahead pages as possible > uncharged migration sources. > > Signed-off-by: Johannes Weiner <[email protected]>
Acked-by: Michal Hocko <[email protected]> > --- > mm/memcontrol.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index fc1d7ca96b9d..76892eb89d26 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -6166,7 +6166,12 @@ void mem_cgroup_migrate(struct page *oldpage, struct > page *newpage, > if (PageCgroupUsed(pc)) > return; > > - /* Re-entrant migration: old page already uncharged? */ > + /* > + * Swapcache readahead pages can get migrated before being > + * charged, and migration from compaction can happen to an > + * uncharged page when the PFN walker finds a page that > + * reclaim just put back on the LRU but has not released yet. > + */ > pc = lookup_page_cgroup(oldpage); > if (!PageCgroupUsed(pc)) > return; > -- > 2.1.2 > -- Michal Hocko SUSE Labs -- 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/
