On Tue, Aug 27, 2019 at 7:50 PM Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > On Tue 27-08-19 19:43:49, Yafang Shao wrote: > > On Tue, Aug 27, 2019 at 6:43 PM Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > > > > > If there are no objection to the patch I will post it as a standalong > > > one. > > > > I have no objection to your patch. It could fix the issue. > > > > I still think that it is not proper to use a new scan_control here as > > it breaks the global reclaim context. > > > > This context switch from global reclaim to memcg reclaim is very > > subtle change to the subsequent processing, that may cause some > > unexpected behavior. > > Why would it break it? Could you be more specific please? > Hmm, I have explained it when replying to Hillf's patch. The most suspcious one is settting target_mem_cgroup here, because we only use it to judge whether it is in global reclaim. While the memcg softlimit reclaim is really in global reclaims. Another example the reclaim_idx, if is not same with reclaim_idx in page allocation context, the reclaimed pages may not be used by the allocator, especially in the direct reclaim. And some other things in scan_control. > > Anyway, we can send this patch as a standalong one. > > Feel free to add: > > > > Acked-by: Yafang Shao <laoar.shao@xxxxxxxxx> > > Thanks! > -- > Michal Hocko > SUSE Labs
