From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f72.google.com (mail-pa0-f72.google.com [209.85.220.72]) by kanga.kvack.org (Postfix) with ESMTP id 88B866B026B for ; Fri, 15 Jul 2016 17:25:31 -0400 (EDT) Received: by mail-pa0-f72.google.com with SMTP id ez1so110071429pab.0 for ; Fri, 15 Jul 2016 14:25:31 -0700 (PDT) Received: from mail-pa0-x22e.google.com (mail-pa0-x22e.google.com. [2607:f8b0:400e:c03::22e]) by mx.google.com with ESMTPS id d186si5997342pfc.72.2016.07.15.14.25.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Jul 2016 14:25:30 -0700 (PDT) Received: by mail-pa0-x22e.google.com with SMTP id pp5so35829464pac.3 for ; Fri, 15 Jul 2016 14:25:30 -0700 (PDT) Date: Fri, 15 Jul 2016 14:25:22 -0700 (PDT) From: David Rientjes Subject: Re: System freezes after OOM In-Reply-To: Message-ID: References: <57837CEE.1010609@redhat.com> <9be09452-de7f-d8be-fd5d-4a80d1cd1ba3@redhat.com> <20160712064905.GA14586@dhcp22.suse.cz> <2d5e1f84-e886-7b98-cb11-170d7104fd13@I-love.SAKURA.ne.jp> <20160713133955.GK28723@dhcp22.suse.cz> <20160713145638.GM28723@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Mikulas Patocka Cc: Michal Hocko , Tetsuo Handa , Ondrej Kozina , Jerome Marchand , Stanislav Kozina , linux-mm@kvack.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com On Fri, 15 Jul 2016, Mikulas Patocka wrote: > > There is no guarantee that _anything_ can return memory to the mempool, > > You misunderstand mempools if you make such claims. > > There is in fact guarantee that objects will be returned to mempool. In > the past I reviewed device mapper thoroughly to make sure that it can make > forward progress even if there is no available memory. > > I don't know what should I tell you if you keep on repeating the same > false claim over and over again. Should I explain mempool oprerations to > you in detail? Or will you find it on your own? > If you are talking about patches you're proposing for 4.8 or any guarantee of memory freeing that the oom killer/reaper will provide in 4.8, that's fine. However, the state of the 4.7 kernel is the same as it was when I fixed this issue that timed out hundreds of our machines and is contradicted by that evidence. Our machines time out after two hours with the oom victim looping forever in mempool_alloc(), so if there was a guarantee that elements would be returned in a completely livelocked kernel in 4.7 or earlier kernels, that would not have been the case. I frankly don't care about your patch reviewing of dm mempool usage when dm_request() livelocked our kernel. Feel free to formally propose patches either for 4.7 or 4.8. -- 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