From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f42.google.com (mail-wg0-f42.google.com [74.125.82.42]) by kanga.kvack.org (Postfix) with ESMTP id 58B319003C8 for ; Tue, 14 Jul 2015 05:28:48 -0400 (EDT) Received: by wgkl9 with SMTP id l9so3827608wgk.1 for ; Tue, 14 Jul 2015 02:28:47 -0700 (PDT) Received: from mail-wg0-f46.google.com (mail-wg0-f46.google.com. [74.125.82.46]) by mx.google.com with ESMTPS id gm12si742764wjc.83.2015.07.14.02.28.46 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 14 Jul 2015 02:28:46 -0700 (PDT) Received: by wgjx7 with SMTP id x7so3809614wgj.2 for ; Tue, 14 Jul 2015 02:28:46 -0700 (PDT) Date: Tue, 14 Jul 2015 11:28:43 +0200 From: Michal Hocko Subject: Re: [BUG REPORT] OOM Killer is invoked while the system still has much memory Message-ID: <20150714092842.GB17660@dhcp22.suse.cz> References: <6D317A699782EA4DB9A0E6266C9219696CA2B3BC@SZXEMA501-MBX.china.huawei.com> <20150714081521.GA17711@dhcp22.suse.cz> <55A4CB68.5060906@huawei.com> <20150714090025.GA17660@dhcp22.suse.cz> <55A4D300.5030704@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55A4D300.5030704@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: To: Xishi Qiu Cc: Xuzhichuang , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "Songjiangtao (mygirlsjt)" , "Zhangwei (FF)" On Tue 14-07-15 17:14:40, Xishi Qiu wrote: > On 2015/7/14 17:00, Michal Hocko wrote: > > > On Tue 14-07-15 16:42:16, Xishi Qiu wrote: > >> On 2015/7/14 16:15, Michal Hocko wrote: > >> > >>> On Tue 14-07-15 07:11:34, Xuzhichuang wrote: > > [...] > >>>> Jul 10 12:33:03 BMS_CNA04 kernel: [18136514.138968] DMA32: 188513*4kB 29459*8kB 2*16kB 2*32kB 1*64kB 0*128kB 0*256kB 1*512kB 0*1024kB 0*2048kB 0*4096kB = 990396kB > >>> > >>> Moreover your allocation request was oreder 2 and you do not have much > >>> memory there because most of the free memory is in order-0-2. > >>> > >> > >> Hi Michal, > >> > >> order=2 -> alloc 16kb memory, and DMA32 still has 2*16kB 2*32kB 1*64kB 1*512kB, > >> so you mean this large buddy block was reclaimed during the moment of oom and > >> print, right? > > > > Not really. Those high order blocks are inaccessible for your GFP_KERNEL > > allocation. See __zone_watermark_ok. > > > > I know, some of them are from reserved memory(MIGRATE_RESERVE), right? No. The watermark is calculated per order. And you have almost all the free memory in the lower orders. From a quick glance it seems that even order-1 allocations wouldn't fit into min watermark. -- 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