From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 9DC5A6B026A for ; Fri, 15 Jul 2016 17:22:03 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id 63so240905144pfx.3 for ; Fri, 15 Jul 2016 14:22:03 -0700 (PDT) Received: from mail-pa0-x230.google.com (mail-pa0-x230.google.com. [2607:f8b0:400e:c03::230]) by mx.google.com with ESMTPS id 64si5780984pfd.183.2016.07.15.14.22.02 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Jul 2016 14:22:02 -0700 (PDT) Received: by mail-pa0-x230.google.com with SMTP id ks6so42596513pab.0 for ; Fri, 15 Jul 2016 14:22:02 -0700 (PDT) Date: Fri, 15 Jul 2016 14:21:54 -0700 (PDT) From: David Rientjes Subject: Re: System freezes after OOM In-Reply-To: Message-ID: References: <20160713133955.GK28723@dhcp22.suse.cz> <20160713145638.GM28723@dhcp22.suse.cz> <201607142001.BJD07258.SMOHFOJVtLFOQF@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Mikulas Patocka Cc: Tetsuo Handa , mhocko@kernel.org, okozina@redhat.com, jmarchan@redhat.com, skozina@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri, 15 Jul 2016, Mikulas Patocka wrote: > > Umm, show me an explicit guarantee where the oom reaper will free memory > > such that other threads may return memory to this process's mempool so it > > can make forward progress in mempool_alloc() without the need of utilizing > > memory reserves. First, it might be helpful to show that the oom reaper > > is ever guaranteed to free any memory for a selected oom victim. > > The function mempool_alloc sleeps with "io_schedule_timeout(5*HZ);" > > So, if the oom reaper frees some memory into the page allocator, the > process that is stuck in mempoo_alloc will sleep for up to 5 seconds, then > it will retry the allocation with "element = pool->alloc(gfp_temp, > pool->pool_data)" (that will allocate from the page allocator) and succed. > No, the state of the 4.7 oom killer does not explicitly guarantee any memory freeing of the victim and there is no guarantee that elements will be returned to the mempool. If you're talking about patches that you're proposing for the 4.8 merge window, please post them with complete changelogs. Thanks. -- 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