From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8BF6EC433DF for ; Fri, 10 Jul 2020 08:26:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5AE50207F9 for ; Fri, 10 Jul 2020 08:26:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5AE50207F9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C7F2B8D0001; Fri, 10 Jul 2020 04:26:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C07BD6B0005; Fri, 10 Jul 2020 04:26:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AD1228D0001; Fri, 10 Jul 2020 04:26:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0078.hostedemail.com [216.40.44.78]) by kanga.kvack.org (Postfix) with ESMTP id 932D06B0002 for ; Fri, 10 Jul 2020 04:26:31 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0597C18029146 for ; Fri, 10 Jul 2020 08:26:31 +0000 (UTC) X-FDA: 77021484582.05.lake96_5411c7226ecc Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id A1FDD18030343 for ; Fri, 10 Jul 2020 08:24:19 +0000 (UTC) X-HE-Tag: lake96_5411c7226ecc X-Filterd-Recvd-Size: 6094 Received: from out30-44.freemail.mail.aliyun.com (out30-44.freemail.mail.aliyun.com [115.124.30.44]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Fri, 10 Jul 2020 08:24:18 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R621e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07488;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=17;SR=0;TI=SMTPD_---0U2HLiLc_1594369452; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U2HLiLc_1594369452) by smtp.aliyun-inc.com(127.0.0.1); Fri, 10 Jul 2020 16:24:13 +0800 Subject: Re: [PATCH v14 07/20] mm/thp: narrow lru locking To: "Kirill A. Shutemov" , Hugh Dickins Cc: Matthew Wilcox , Johannes Weiner , akpm@linux-foundation.org, mgorman@techsingularity.net, tj@kernel.org, khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com, yang.shi@linux.alibaba.com, lkp@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, shakeelb@google.com, iamjoonsoo.kim@lge.com, richard.weiyang@gmail.com References: <1593752873-4493-1-git-send-email-alex.shi@linux.alibaba.com> <1593752873-4493-8-git-send-email-alex.shi@linux.alibaba.com> <124eeef1-ff2b-609e-3bf6-a118100c3f2a@linux.alibaba.com> <20200706113513.GY25523@casper.infradead.org> <20200709154816.wieg5thfejyv2h2l@box> From: Alex Shi Message-ID: Date: Fri, 10 Jul 2020 16:23:35 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200709154816.wieg5thfejyv2h2l@box> Content-Type: text/plain; charset=gbk X-Rspamd-Queue-Id: A1FDD18030343 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 Content-Transfer-Encoding: quoted-printable 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: =D4=DA 2020/7/9 =CF=C2=CE=E711:48, Kirill A. Shutemov =D0=B4=B5=C0: > On Mon, Jul 06, 2020 at 09:52:34PM -0700, Hugh Dickins wrote: >> On Mon, 6 Jul 2020, Matthew Wilcox wrote: >>> On Mon, Jul 06, 2020 at 05:15:09PM +0800, Alex Shi wrote: >>>> Hi Kirill & Johannes & Matthew, >> >> Adding Kirill, who was in patch's Cc list but not mail's Cc list. >> >> I asked Alex to direct this one particularly to Kirill and Johannes >> and Matthew because (and I regret that the commit message still does >> not make this at all clear) this patch changes the lock ordering: >> which for years has been lru_lock outside memcg move_lock outside >> i_pages lock, but here inverted to lru_lock inside i_pages lock. >> >> I don't see a strong reason to have them one way round or the other, >> and think Alex is right that they can safely be reversed here: but >> he doesn't actually give any reason for doing so (if cleanup, then >> I think the cleanup should have been taken further), and no reason >> for doing so as part of this series. >=20 > I've looked around and changing order of lru_lock wrt. i_pages lock see= ms > safe. I don't have much experience with memcg move_lock. Hi Kirill, Thanks for response! mem_cgroup_move_account(page) could not reach here since 2 blocks, 1, isolate_lru_page() before it will take page from lru, this compete for page reclaim path, list non-null. 2, try_lock_page in it, will guard split_huge_page(), !list. >=20 > Alex, if you are going ahead with the patch, please document the lockin= g > order. We have some locking orders listed at the beginning of filemap.c > and rmap.c. Thanks for reminder! Hugh Dickins did this in above 2 files at the end of patchset, any commen= ts? diff --git a/mm/filemap.c b/mm/filemap.c index f0ae9a6308cb..1b42aaae4d3e 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -101,8 +101,8 @@ * ->swap_lock (try_to_unmap_one) * ->private_lock (try_to_unmap_one) * ->i_pages lock (try_to_unmap_one) - * ->pgdat->lru_lock (follow_page->mark_page_accessed) - * ->pgdat->lru_lock (check_pte_range->isolate_lru_page) + * ->lruvec->lru_lock (follow_page->mark_page_accessed) + * ->lruvec->lru_lock (check_pte_range->isolate_lru_page) * ->private_lock (page_remove_rmap->set_page_dirty) * ->i_pages lock (page_remove_rmap->set_page_dirty) * bdi.wb->list_lock (page_remove_rmap->set_page_dirty) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d5e56be42f21..926d7d95dc1d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3057,7 +3057,7 @@ void __memcg_kmem_uncharge_page(struct page *page, = int order) #ifdef CONFIG_TRANSPARENT_HUGEPAGE =20 /* - * Because tail pages are not marked as "used", set it. We're under + * Because tail pages are not marked as "used", set it. Don't need * lruvec->lru_lock and migration entries setup in all page mappings. */ void mem_cgroup_split_huge_fixup(struct page *head) diff --git a/mm/rmap.c b/mm/rmap.c index 5fe2dedce1fc..7fbc382e6f9e 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -28,12 +28,12 @@ * hugetlb_fault_mutex (hugetlbfs specific page fault mutex) * anon_vma->rwsem * mm->page_table_lock or pte_lock - * pgdat->lru_lock (in mark_page_accessed, isolate_lru_pag= e) * swap_lock (in swap_duplicate, swap_info_get) * mmlist_lock (in mmput, drain_mmlist and others) * mapping->private_lock (in __set_page_dirty_buffers) - * mem_cgroup_{begin,end}_page_stat (memcg->move_lock) + * lock_page_memcg move_lock (in __set_page_dirty_buff= ers) * i_pages lock (widely used) + * lock_page_lruvec_irq lruvec->lru_lock * inode->i_lock (in set_page_dirty's __mark_inode_dirty= ) * bdi.wb->list_lock (in set_page_dirty's __mark_inode_d= irty) * sb_lock (within inode_lock in fs/fs-writeback.c) >=20 > local_irq_disable() also deserves a comment. >=20 yes, I will add a comment for this. Do you mind give reviewed-by for this= patch? Thanks Alex