From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934636AbcIUOrp (ORCPT ); Wed, 21 Sep 2016 10:47:45 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:37297 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S933316AbcIUOrn (ORCPT ); Wed, 21 Sep 2016 10:47:43 -0400 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: <87eg54rx1w.fsf@linux.vnet.ibm.com> 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> <87eg54rx1w.fsf@linux.vnet.ibm.com> Date: Wed, 21 Sep 2016 20:17:27 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16092114-0028-0000-0000-000005A78444 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00005797; HX=3.00000240; KW=3.00000007; PH=3.00000004; SC=3.00000185; SDB=6.00759883; UDB=6.00361334; IPR=6.00534295; BA=6.00004744; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00012738; XFM=3.00000011; UTC=2016-09-21 14:47:39 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16092114-0029-0000-0000-00002F6CE3FF Message-Id: <87eg4dwbr4.fsf@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-09-21_09:,, 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=8.0.1-1609020000 definitions=main-1609210270 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Aneesh Kumar K.V" writes: > 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 ? > Even though we have the issues of migration failures due to pinned and THP pages in ZONE_CMA, overall the code is simpler. IMHO we should get this upstream now and work on solving those issues later. You can add for the complete series. Reviewed-by: Aneesh Kumar K.V -aneesh