Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753418AbaJQHpW (ORCPT ); Fri, 17 Oct 2014 03:45:22 -0400 Received: from [42.62.48.242] ([42.62.48.242]:63453 "EHLO manager.mioffice.cn" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751403AbaJQHpU (ORCPT ); Fri, 17 Oct 2014 03:45:20 -0400 From: =?gb2312?B?1uy71A==?= To: Laura Abbott , "rjw@rjwysocki.net" , "len.brown@intel.com" , "pavel@ucw.cz" , "m.szyprowski@samsung.com" , "akpm@linux-foundation.org" , "mina86@mina86.com" , "aneesh.kumar@linux.vnet.ibm.com" , "iamjoonsoo.kim@lge.com" , "hannes@cmpxchg.org" , "riel@redhat.com" , "mgorman@suse.de" , "minchan@kernel.org" , "nasa4836@gmail.com" , "ddstreet@ieee.org" , "hughd@google.com" , "mingo@kernel.org" , "rientjes@google.com" , "peterz@infradead.org" , "keescook@chromium.org" , "atomlin@redhat.com" , "raistlin@linux.it" , "axboe@fb.com" , "paulmck@linux.vnet.ibm.com" , "kirill.shutemov@linux.intel.com" , "n-horiguchi@ah.jp.nec.com" , "k.khlebnikov@samsung.com" , "msalter@redhat.com" , "deller@gmx.de" , "tangchen@cn.fujitsu.com" , "ben@decadent.org.uk" , "akinobu.mita@gmail.com" , "vbabka@suse.cz" , "sasha.levin@oracle.com" , "vdavydov@parallels.com" , "suleiman@google.com" CC: "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" , "linux-mm@kvack.org" Subject: Re: [PATCH 0/4] (CMA_AGGRESSIVE) Make CMA memory be more aggressive about allocation Thread-Topic: [PATCH 0/4] (CMA_AGGRESSIVE) Make CMA memory be more aggressive about allocation Thread-Index: AQHP6PJVOSZsZeZKBkSR9KhOfKwh0g== Date: Fri, 17 Oct 2014 07:44:26 +0000 Message-ID: References: <1413430551-22392-1-git-send-email-zhuhui@xiaomi.com> <543F8812.2020002@codeaurora.org> Accept-Language: zh-CN, en-US Content-Language: zh-CN X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [106.37.216.50] x-esetresult: clean, is OK x-esetid: 16754838BAB46B0E423415 Content-Type: text/plain; charset="gb2312" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id s9H7jRFs009866 On 10/16/14 16:56, Laura Abbott wrote: > On 10/15/2014 8:35 PM, Hui Zhu wrote: >> In fallbacks of page_alloc.c, MIGRATE_CMA is the fallback of >> MIGRATE_MOVABLE. >> MIGRATE_MOVABLE will use MIGRATE_CMA when it doesn't have a page in >> order that Linux kernel want. >> >> If a system that has a lot of user space program is running, for >> instance, an Android board, most of memory is in MIGRATE_MOVABLE and >> allocated. Before function __rmqueue_fallback get memory from >> MIGRATE_CMA, the oom_killer will kill a task to release memory when >> kernel want get MIGRATE_UNMOVABLE memory because fallbacks of >> MIGRATE_UNMOVABLE are MIGRATE_RECLAIMABLE and MIGRATE_MOVABLE. >> This status is odd. The MIGRATE_CMA has a lot free memory but Linux >> kernel kill some tasks to release memory. >> >> This patch series adds a new function CMA_AGGRESSIVE to make CMA memory >> be more aggressive about allocation. >> If function CMA_AGGRESSIVE is available, when Linux kernel call function >> __rmqueue try to get pages from MIGRATE_MOVABLE and conditions allow, >> MIGRATE_CMA will be allocated as MIGRATE_MOVABLE first. If MIGRATE_CMA >> doesn't have enough pages for allocation, go back to allocate memory from >> MIGRATE_MOVABLE. >> Then the memory of MIGRATE_MOVABLE can be kept for MIGRATE_UNMOVABLE and >> MIGRATE_RECLAIMABLE which doesn't have fallback MIGRATE_CMA. >> > > It's good to see another proposal to fix CMA utilization. Thanks Laura. Do you have > any data about the success rate of CMA contiguous allocation after > this patch series? I played around with a similar approach of using > CMA for MIGRATE_MOVABLE allocations and found that although utilization > did increase, contiguous allocations failed at a higher rate and were > much slower. I see what this series is trying to do with avoiding > allocation from CMA pages when a contiguous allocation is progress. > My concern is that there would still be problems with contiguous > allocation after all the MIGRATE_MOVABLE fallback has happened. I did some test with the cma_alloc_counter and cma-aggressive-shrink in a android board that has 1g memory. Run some apps to make free CMA close to the value of cma_aggressive_free_min(500 pages). A driver Begin to request CMA more than 10 times. Each time, it will request more than 3000 pages. I don't have established number for that because it is really hard to get a fail. I think the success rate is over 95% at least. And I think maybe the isolate fail has relation with page alloc and free code. Maybe let zone->lock protect more code can handle this issue. Thanks, Hui > > Thanks, > Laura > ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?