From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754632Ab1JKNGD (ORCPT ); Tue, 11 Oct 2011 09:06:03 -0400 Received: from mailout3.w1.samsung.com ([210.118.77.13]:59705 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752285Ab1JKNGB (ORCPT ); Tue, 11 Oct 2011 09:06:01 -0400 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=us-ascii Date: Tue, 11 Oct 2011 15:05:47 +0200 From: Marek Szyprowski Subject: RE: [Linaro-mm-sig] [PATCHv16 0/9] Contiguous Memory Allocator In-reply-to: <4E9427B6.8050306@stericsson.com> To: "'Maxime Coquelin'" 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 Message-id: <00cb01cc8816$7e474600$7ad5d200$%szyprowski@samsung.com> Organization: SPRC X-Mailer: Microsoft Office Outlook 12.0 Content-language: pl Thread-index: AcyICRvWRrwjXzW0TbaP67J5/S+UDAADSj9w 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> <4E9427B6.8050306@stericsson.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tuesday, October 11, 2011 1:26 PM Maxime Coquelin wrote: > 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(). Thanks for hint. I've managed to reproduce this issue. I will post fix asap. > > 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? OOM was never triggered. Best regards -- Marek Szyprowski Samsung Poland R&D Center