From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751519AbcIAFrl (ORCPT ); Thu, 1 Sep 2016 01:47:41 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:47960 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751010AbcIAFrh (ORCPT ); Thu, 1 Sep 2016 01:47:37 -0400 X-IBM-Helo: d03dlp03.boulder.ibm.com X-IBM-MailFrom: aneesh.kumar@linux.vnet.ibm.com From: "Aneesh Kumar K.V" To: Joonsoo Kim Cc: Andrew Morton , Rik van Riel , Johannes Weiner , Mel Gorman , Laura Abbott , Minchan Kim , Marek Szyprowski , Michal Nazarewicz , Vlastimil Babka , Linux Memory Management List , LKML Subject: Re: [PATCH v5 0/6] Introduce ZONE_CMA In-Reply-To: <20160831080300.GB22757@js1304-P5Q-DELUXE> References: <1472447255-10584-1-git-send-email-iamjoonsoo.kim@lge.com> <8737lnudq6.fsf@linux.vnet.ibm.com> <87shtmsfpy.fsf@linux.vnet.ibm.com> <20160831080300.GB22757@js1304-P5Q-DELUXE> Date: Thu, 01 Sep 2016 11:17:23 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16090105-0004-0000-0000-00001043F60A X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00005690; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000184; SDB=6.00752384; UDB=6.00355728; IPR=6.00525186; BA=6.00004683; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00012542; XFM=3.00000011; UTC=2016-09-01 05:47:32 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16090105-0005-0000-0000-0000787C50E6 Message-Id: <87eg54rx1w.fsf@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-09-01_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1609010059 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Joonsoo Kim writes: > On Tue, Aug 30, 2016 at 04:09:37PM +0530, Aneesh Kumar K.V wrote: >> Joonsoo Kim writes: >> >> > 2016-08-29 18:27 GMT+09:00 Aneesh Kumar K.V : >> >> js1304@gmail.com writes: >> >> >> >>> From: Joonsoo Kim >> >>> >> >>> Hello, >> >>> >> >>> Changes from v4 >> >>> o Rebase on next-20160825 >> >>> o Add general fix patch for lowmem reserve >> >>> o Fix lowmem reserve ratio >> >>> o Fix zone span optimizaion per Vlastimil >> >>> o Fix pageset initialization >> >>> o Change invocation timing on cma_init_reserved_areas() >> >> >> >> I don't see much information regarding how we interleave between >> >> ZONE_CMA and other zones for movable allocation. Is that explained in >> >> any of the patch ? The fair zone allocator got removed by >> >> e6cbd7f2efb433d717af72aa8510a9db6f7a7e05 >> > >> > Interleaving would not work since the fair zone allocator policy is removed. >> > I don't think that it's a big problem because it is just matter of >> > timing to fill >> > up the memory. Eventually, memory on ZONE_CMA will be fully used in >> > any case. >> >> Does that mean a CMA allocation will now be slower because in most case we >> will need to reclaim ? The zone list will now have ZONE_CMA in the >> beginning right ? > > ZONE_CMA will be used first but I don't think that CMA allocation will > be slower. In most case, memory would be fully used (usually > by page cache). So, we need reclaim or migration in any case. Considering that the upstream kernel doesn't allow migration of THP pages, this would mean that migrate will fail in most case if we have THP enabled and the THP allocation request got satisfied via ZONE_CMA. Isn't that going to be a problem ? -aneesh