From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 0F7896B0272 for ; Wed, 21 Sep 2016 10:47:45 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id l132so26516108wmf.0 for ; Wed, 21 Sep 2016 07:47:45 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id v132si29817708wmd.83.2016.09.21.07.47.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Sep 2016 07:47:43 -0700 (PDT) Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u8LEiORI121345 for ; Wed, 21 Sep 2016 10:47:42 -0400 Received: from e38.co.us.ibm.com (e38.co.us.ibm.com [32.97.110.159]) by mx0b-001b2d01.pphosted.com with ESMTP id 25knvrjeyu-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 21 Sep 2016 10:47:41 -0400 Received: from localhost by e38.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 21 Sep 2016 08:47:40 -0600 From: "Aneesh Kumar K.V" 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 Message-Id: <87eg4dwbr4.fsf@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: 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 "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 -- 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