On Wed, Mar 22, 2017 at 10:11:33PM +0800, Yisheng Xie wrote: > From: Yisheng Xie <xieyisheng1@xxxxxxxxxx> > > By reviewing code, I find that when enter do_try_to_free_pages, the > may_thrash is always clear, and it will retry shrink zones to tap > cgroup's reserves memory by setting may_thrash when the former > shrink_zones reclaim nothing. > > However, when memcg is disabled or on legacy hierarchy, or there do not > have any memcg protected by low limit, it should not do this useless > retry at all, for we do not have any cgroup's reserves memory to tap, > and we have already done hard work but made no progress, which as Michal > pointed out in former version, we are trying hard to control the retry > logical of page alloctor, and the current additional round of reclaim is > just lame. > > Therefore, to avoid this unneeded retrying and make code more readable, > we remove the may_thrash field in scan_control, instead, introduce > memcg_low_reclaim and memcg_low_skipped, and only retry when > memcg_low_skipped, by setting memcg_low_reclaim. > > Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx> > Acked-by: Michal Hocko <mhocko@xxxxxxxx> > Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx> > Suggested-by: Michal Hocko <mhocko@xxxxxxxxxx> > Suggested-by: Shakeel Butt <shakeelb@xxxxxxxxxx> > Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Thanks Yisheng! -- 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>
