From patchwork Wed Nov 11 09:28:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vlastimil Babka X-Patchwork-Id: 11897273 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 03D13921 for ; Wed, 11 Nov 2020 09:28:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B240C20756 for ; Wed, 11 Nov 2020 09:28:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B240C20756 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B7D3E6B006C; Wed, 11 Nov 2020 04:28:25 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 6D9236B0074; Wed, 11 Nov 2020 04:28:25 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3C54E6B006E; Wed, 11 Nov 2020 04:28:25 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0237.hostedemail.com [216.40.44.237]) by kanga.kvack.org (Postfix) with ESMTP id F084B6B0068 for ; Wed, 11 Nov 2020 04:28:24 -0500 (EST) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 9EB9B180AD802 for ; Wed, 11 Nov 2020 09:28:24 +0000 (UTC) X-FDA: 77471611728.25.shape15_1d07e20272fc Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 62F011804E3A1 for ; Wed, 11 Nov 2020 09:28:24 +0000 (UTC) X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,vbabka@suse.cz,,RULES_HIT:30054:30070,0,RBL:195.135.220.15:@suse.cz:.lbl8.mailshell.net-62.2.6.2 64.100.201.201;04y8hgqfmpcuuqm6dg5dzszg7wxfjop4bea475hr67d91mg4baezfprtcouxwj6.figawdjkaeia47kyxzecmoetoqyhsipfptu1iamkgz8iohs3iombni6owyfxgjm.c-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:69,LUA_SUMMARY:none X-HE-Tag: shape15_1d07e20272fc X-Filterd-Recvd-Size: 4934 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf45.hostedemail.com (Postfix) with ESMTP for ; Wed, 11 Nov 2020 09:28:23 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 5C293ABD6; Wed, 11 Nov 2020 09:28:22 +0000 (UTC) From: Vlastimil Babka To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko , Pavel Tatashin , David Hildenbrand , Oscar Salvador , Joonsoo Kim , Vlastimil Babka Subject: [PATCH v3 0/7] disable pcplists during memory offline Date: Wed, 11 Nov 2020 10:28:05 +0100 Message-Id: <20201111092812.11329-1-vbabka@suse.cz> X-Mailer: git-send-email 2.29.1 MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Changes since v2 [8]: - add acks/reviews (thanks David and Oscar) - small wording and style changes - rebase to next-20201111 Changes since v1 [7]: - add acks/reviews (thanks David and Michal) - drop "mm, page_alloc: make per_cpu_pageset accessible only after init" as that's orthogonal and needs more consideration - squash "mm, page_alloc: drain all pcplists during memory offline" into the last patch, and move new zone_pcp_* functions into mm/page_alloc. As such, the new 'force all cpus' param of __drain_all_pages() is never exported outside page_alloc.c so I didn't add a new wrapper function to hide the bool - keep pcp_batch_high_lock a mutex as offline_pages is synchronized anyway, as suggested by Michal. Thus we don't need atomic variable and sync around it, and patch is much smaller. If alloc_contic_range() wants to use the new functionality and keep parallelism, we can add that on top. As per the discussions [1] [2] this is an attempt to implement David's suggestion that page isolation should disable pcplists to avoid races with page freeing in progress. This is done without extra checks in fast paths, as explained in Patch 9. The repeated draining done by [2] is then no longer needed. Previous version (RFC) is at [3]. The RFC tried to hide pcplists disabling/enabling into page isolation, but it wasn't completely possible, as memory offline does not unisolation. Michal suggested an explicit API in [4] so that's the current implementation and it seems indeed nicer. Once we accept that page isolation users need to do explicit actions around it depending on the needed guarantees, we can also IMHO accept that the current pcplist draining can be also done by the callers, which is more effective. After all, there are only two users of page isolation. So patch 6 does effectively the same thing as Pavel proposed in [5], and patch 7 implement stronger guarantees only for memory offline. If CMA decides to opt-in to the stronger guarantee, it can be added later. Patches 1-5 are preparatory cleanups for pcplist disabling. Patchset was briefly tested in QEMU so that memory online/offline works, but I haven't done a stress test that would prove the race fixed by [2] is eliminated. Note that patch 7 could be avoided if we instead adjusted page freeing in shown in [6], but I believe the current implementation of disabling pcplists is not too much complex, so I would prefer this instead of adding new checks and longer irq-disabled section into page freeing hotpaths. [1] https://lore.kernel.org/linux-mm/20200901124615.137200-1-pasha.tatashin@soleen.com/ [2] https://lore.kernel.org/linux-mm/20200903140032.380431-1-pasha.tatashin@soleen.com/ [3] https://lore.kernel.org/linux-mm/20200907163628.26495-1-vbabka@suse.cz/ [4] https://lore.kernel.org/linux-mm/20200909113647.GG7348@dhcp22.suse.cz/ [5] https://lore.kernel.org/linux-mm/20200904151448.100489-3-pasha.tatashin@soleen.com/ [6] https://lore.kernel.org/linux-mm/3d3b53db-aeaa-ff24-260b-36427fac9b1c@suse.cz/ [7] https://lore.kernel.org/linux-mm/20200922143712.12048-1-vbabka@suse.cz/ [8] https://lore.kernel.org/linux-mm/20201008114201.18824-1-vbabka@suse.cz/ Vlastimil Babka (7): mm, page_alloc: clean up pageset high and batch update mm, page_alloc: calculate pageset high and batch once per zone mm, page_alloc: remove setup_pageset() mm, page_alloc: simplify pageset_update() mm, page_alloc: cache pageset high and batch in struct zone mm, page_alloc: move draining pcplists to page isolation users mm, page_alloc: disable pcplists during memory offline include/linux/mmzone.h | 6 ++ mm/internal.h | 2 + mm/memory_hotplug.c | 27 +++--- mm/page_alloc.c | 195 ++++++++++++++++++++++++----------------- mm/page_isolation.c | 10 +-- 5 files changed, 141 insertions(+), 99 deletions(-)