From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f174.google.com (mail-pd0-f174.google.com [209.85.192.174]) by kanga.kvack.org (Postfix) with ESMTP id 886BA6B0069 for ; Fri, 28 Nov 2014 02:15:40 -0500 (EST) Received: by mail-pd0-f174.google.com with SMTP id w10so6139851pde.19 for ; Thu, 27 Nov 2014 23:15:40 -0800 (PST) Received: from lgeamrelo04.lge.com (lgeamrelo04.lge.com. [156.147.1.127]) by mx.google.com with ESMTP id nr9si14941235pbc.1.2014.11.27.23.15.37 for ; Thu, 27 Nov 2014 23:15:39 -0800 (PST) Message-ID: <54782118.5040405@lge.com> Date: Fri, 28 Nov 2014 16:15:36 +0900 From: Gioh Kim MIME-Version: 1.0 Subject: [LSF/MM ATTEND] Improving CMA References: <5473E146.7000503@codeaurora.org> <20141127061204.GA6850@js1304-P5Q-DELUXE> <5476D60D.4030506@lge.com> In-Reply-To: <5476D60D.4030506@lge.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Joonsoo Kim , Laura Abbott Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, zhuhui@xiaomi.com, minchan@kernel.org, SeongJae Park , mgorman@suse.de > > > 2014-11-27 i??i?? 3:12i?? Joonsoo Kim i?'(e??) i?' e,?: >> On Mon, Nov 24, 2014 at 05:54:14PM -0800, Laura Abbott wrote: >>> There have been a number of patch series posted designed to improve various >>> aspects of CMA. A sampling: >>> >>> https://lkml.org/lkml/2014/10/15/623 >>> http://marc.info/?l=linux-mm&m=141571797202006&w=2 >>> https://lkml.org/lkml/2014/6/26/549 >>> >>> As far as I can tell, these are all trying to fix real problems with CMA but >>> none of them have moved forward very much from what I can tell. The goal of >>> this session would be to come out with an agreement on what are the biggest >>> problems with CMA and the best ways to solve them. >> >> I also tried to solve problem from CMA, that is, reserved memory >> utilization. >> >> https://lkml.org/lkml/2014/5/28/64 >> >> While playing that patchset, I found serious problem about free page >> counting, so I stopped to develop it for a while and tried to fix it. >> Now, it is fixed by me and I can continue my patchset. >> >> https://lkml.org/lkml/2014/10/31/69 >> >> I heard that Minchan suggests new CMA zone like movable zone, and, I >> think that it would be the way to go. But, it would be a long-term goal >> and I'd like to solve utilization problem with my patchset for now. >> It is the biggest issue and it already forces someone to develop >> out of tree solution. It's not good that out of tree solution is used >> more and more in the product so I'd like to fix it quickly at first >> stage. >> >> I think that CMA have big potential. If we fix problems of CMA >> completely, it can be used for many places. One such case in my mind >> is hugetlb or THP. Until now, hugetlb uses reserved approach, that is >> very inefficient. System administrator carefully set the number of >> reserved hugepage according to whole system workload. And application >> can't use it freely, because it is very limited and managed resource. >> If we use CMA for hugetlb, we can easily allocate hugepage and >> application can use hugepages more freely. >> >> Anyway, I'd like to attend LSF/MM and discuss this topic. >> >> Thanks. >> > > Until now, I've used CMA with 2 out-of-tree patches: > 1. https://lkml.org/lkml/2012/8/31/313 : Laura's patch > 2. https://lkml.org/lkml/2014/5/28/64 : Joonsoo's patch > > And one merged patch by me: https://lkml.org/lkml/2014/9/4/78 > > With them, my platform could've worked but it still had free-page-counting problem. > > I think if Joonsoo's patch [2] is merged into mainline, CMA can be stable and useful. > Allocation latency Minchan mentioned is not problem for my platform. > CMA allocation is not often and limited to only one drivers. > > Allocation guarantee is, I hope, fixed with my patch (https://lkml.org/lkml/2014/9/4/78) at least in my platform. > My platform had worked for several hours but it lacks heavy load test. > I have a plan to use CMA for massive product next year. > > I'd like to attend LSF/MM and discuss this topic too. I'm sending LSF/MM attend request as Joonsoo did. Thanks. -- 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