From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id A6FC56B002C for ; Tue, 11 Oct 2011 07:29:58 -0400 (EDT) Message-ID: <4E9427B6.8050306@stericsson.com> Date: Tue, 11 Oct 2011 13:25:42 +0200 From: Maxime Coquelin MIME-Version: 1.0 Subject: Re: [Linaro-mm-sig] [PATCHv16 0/9] Contiguous Memory Allocator References: <1317909290-29832-1-git-send-email-m.szyprowski@samsung.com> <4E92E003.4060901@stericsson.com> <00b001cc87e5$dc818cc0$9584a640$%szyprowski@samsung.com> <4E93F088.60006@stericsson.com> <00b301cc8803$93b5b3e0$bb211ba0$%szyprowski@samsung.com> In-Reply-To: <00b301cc8803$93b5b3e0$bb211ba0$%szyprowski@samsung.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Marek Szyprowski Cc: "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-media@vger.kernel.org" , "linux-mm@kvack.org" , "linaro-mm-sig@lists.linaro.org" , 'Daniel Walker' , 'Russell King' , 'Arnd Bergmann' , 'Jonathan Corbet' , 'Mel Gorman' , 'Chunsang Jeong' , 'Michal Nazarewicz' , 'Dave Hansen' , 'Jesse Barker' , 'Kyungmin Park' , 'Ankita Garg' , 'Andrew Morton' , 'KAMEZAWA Hiroyuki' , "benjamin.gaignard@linaro.org" , Ludovic BARRE , "vincent.guittot@linaro.org" On 10/11/2011 12:50 PM, Marek Szyprowski wrote: > Hello, > > On Tuesday, October 11, 2011 9:30 AM Maxime Coquelin wrote: > >> On 10/11/2011 09:17 AM, Marek Szyprowski wrote: >>> On Monday, October 10, 2011 2:08 PM Maxime Coquelin wrote: >>> >>> During our stress tests, we encountered some problems : >>> >>> 1) Contiguous allocation lockup: >>> When system RAM is full of Anon pages, if we try to allocate a >>> contiguous buffer greater than the min_free value, we face a >>> dma_alloc_from_contiguous lockup. >>> The expected result would be dma_alloc_from_contiguous() to fail. >>> The problem is reproduced systematically on our side. >>> Thanks for the report. Do you use Android's lowmemorykiller? I haven't >>> tested CMA on Android kernel yet. I have no idea how it will interfere >>> with Android patches. >>> >> The software used for this test (v16) is a generic 3.0 Kernel and a >> minimal filesystem using Busybox. > I'm really surprised. Could you elaborate a bit how to trigger this issue? At system startup, I drop caches (sync && echo 3 > /proc/sys/vm/drop_caches) and check how much memory is free. For example, in my case, only 15MB is used on the 270MB available on the system, so I got 255MB of free memory. Note that the min_free is 4MB in my case. In userspace, I allocate 230MB using malloc(), the free memory is now 25MB. Finaly, I ask for a contiguous allocation of 64MB using CMA, the result is a lockup in dma_alloc_from_contiguous(). > I've did several tests and I never get a lockup. Allocation failed from time > to time though. When it succeed, what is the behaviour on your side? Is the OOM triggered? Regards, Maxime -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org