From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx142.postini.com [74.125.245.142]) by kanga.kvack.org (Postfix) with SMTP id 040626B0036 for ; Sat, 1 Jun 2013 06:29:09 -0400 (EDT) Received: by mail-ye0-f180.google.com with SMTP id r11so143650yen.11 for ; Sat, 01 Jun 2013 03:29:08 -0700 (PDT) Date: Sat, 1 Jun 2013 12:29:05 +0200 From: Michal Hocko Subject: Re: [patch] mm, memcg: add oom killer delay Message-ID: <20130601102905.GB19474@dhcp22.suse.cz> References: <20130530150539.GA18155@dhcp22.suse.cz> <20130531081052.GA32491@dhcp22.suse.cz> <20130531112116.GC32491@dhcp22.suse.cz> <20130601061151.GC15576@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130601061151.GC15576@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: David Rientjes , Andrew Morton , KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org On Sat 01-06-13 02:11:51, Johannes Weiner wrote: [...] > I'm currently messing around with the below patch. When a task faults > and charges under OOM, the memcg is remembered in the task struct and > then made to sleep on the memcg's OOM waitqueue only after unwinding > the page fault stack. With the kernel OOM killer disabled, all tasks > in the OOMing group sit nicely in > > mem_cgroup_oom_synchronize > pagefault_out_of_memory > mm_fault_error > __do_page_fault > page_fault > 0xffffffffffffffff > > regardless of whether they were faulting anon or file. They do not > even hold the mmap_sem anymore at this point. > > [ I kept syscalls really simple for now and just have them return > -ENOMEM, never trap them at all (just like the global OOM case). > It would be more work to have them wait from a flatter stack too, > but it should be doable if necessary. ] > > I suggested this at the MM summit and people were essentially asking > if I was feeling well, so maybe I'm still missing a gaping hole in > this idea. I didn't get to look at the patch (will do on Monday) but it doesn't sounds entirely crazy. Well, we would have to drop mmap_sem so things have to be rechecked but we are doing that already with VM_FAULT_RETRY in some archs so it should work. > Patch only works on x86 as of now, on other architectures memcg OOM > will invoke the global OOM killer. [...] -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org