On Sun, 16 Feb 2014, Weijie Yang wrote: > On Sun, Feb 16, 2014 at 12:00 PM, Hugh Dickins <hughd@xxxxxxxxxx> wrote: > > On Sun, 16 Feb 2014, Weijie Yang wrote: > > > >> In putback_inactive_pages() and move_active_pages_to_lru(), > >> lruvec is already an input parameter and pages are all from this lruvec, > >> therefore there is no need to call mem_cgroup_page_lruvec() in loop. > >> > >> Signed-off-by: Weijie Yang <weijie.yang@xxxxxxxxxxx> > > > > Looks plausible but I believe it's incorrect. The lruvec passed in > > is the one we took the pages from, but there's a small but real chance > > that the page has become uncharged meanwhile, and should now be put back > > on the root_mem_cgroup's lruvec instead of the original memcg's lruvec. > > Hi Hugh, > > Thanks for your review. > Frankly speaking, I am not very sure about it, that is why I add a RFC tag here. > So, do we need update the reclaim_stat meanwhile as we change the lruvec? No, it's not worth bothering about, it's only for stats and this is an unlikely case; whereas wrong memcg can be a significant correctness issue. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>