On Sat 26-05-18 15:37:05, Shakeel Butt wrote: > On Sat, May 26, 2018 at 11:51 AM, Vladimir Davydov > <vdavydov.dev@xxxxxxxxx> wrote: > > On Fri, May 25, 2018 at 11:55:01AM -0700, Shakeel Butt wrote: > >> Based on several conditions the kernel can decide to force charge an > >> allocation for a memcg i.e. overcharge memcg->memory and memcg->memsw > >> counters. Do the same for memcg->kmem counter too. In cgroup-v1, this > >> bug can cause a __GFP_NOFAIL kmem allocation fail if an explicit limit > >> on kmem counter is set and reached. > > > > memory.kmem.limit is broken and unlikely to ever be fixed as this knob > > was deprecated in cgroup-v2. The fact that hitting the limit doesn't > > trigger reclaim can result in unexpected behavior from user's pov, like > > getting ENOMEM while listing a directory. Bypassing the limit for NOFAIL > > allocations isn't going to fix those problem. > > I understand that fixing NOFAIL will not fix all other issues but it > still is better than current situation. IMHO we should keep fixing > kmem bit by bit. > > One crazy idea is to just break it completely by force charging all the time. What is the limit good for then? Accounting? -- Michal Hocko SUSE Labs
