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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 9E22CC352BE for ; Fri, 17 Apr 2020 00:38:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7CEB62076D for ; Fri, 17 Apr 2020 00:38:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587083924; bh=dsfVZcmcKJN537QBgK6FGyP7iZmiLTZwvWWD2lBwjq4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=QTGRXIM1gVRkpuS+fR81uvGT8NbpH5bTYNRpUCC5EsMBGCp9BNfdST/DxG0IvslvC GoF254oazuR8Ki/Yg4txpQeahRc8arRIesQYRQ1lV2L4Ppcpl9FGWnsnXr2nyBJvYG iMKUbiHy9qeqoZhdKfRQvY3A+Fd1/2OCwMi4niWs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728296AbgDQAin (ORCPT ); Thu, 16 Apr 2020 20:38:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726114AbgDQAin (ORCPT ); Thu, 16 Apr 2020 20:38:43 -0400 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E10AFC061A0C for ; Thu, 16 Apr 2020 17:38:41 -0700 (PDT) Received: by mail-pj1-x1043.google.com with SMTP id t40so322236pjb.3 for ; Thu, 16 Apr 2020 17:38:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=40k/XtvgB9LVenFiOiVygQS7HVI2RZC9x/MgUNMGQ+8=; b=DGa99OeHcgqul2lpIMRadFKqrPltY/0DTJCaYLgH/Wx7/RcFpsXtlnXMp+HFBSviDs G89HKv3XqIYnZlVuoNVXNSMXVX8A8uhnzr6sUz5QZ25Gk+fMU6r7aLmEsyJE3shFQfp6 fuvPFrgI3jJiaXT+dvdx/4YXfAvK1h8Xf9sqvoEBSHmZBWP+rPshVdKoOd+61yubtEmp J3V9hOlmoans53p8dps1e1GV7RDviUoctZikYRwb7+yW6GAaTv3nxSW0a2YAZg+KLE5Q a3FoYQNrNbN06uFxKjvsuQKQ12QTNFCEwsXr9/iPOU2bYV9fa7uV9proDHzw+RY47Oml u7+A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=40k/XtvgB9LVenFiOiVygQS7HVI2RZC9x/MgUNMGQ+8=; b=meH4uhBRZhHb/D2ZZuh398DQladnUES20OZdRebcDnON8J3YkxNONjevr7M88oS2ce bh2lq8DfUR3JDXmCeozmzRA9FZc2lan/qUYDOds+XSANl/0rbs1BbBLzxzqf8L4XcPXE dlMpvlTstNB2cVLSTdcF/7TV/3Pa1sS4LxaqorOnziITyHIJ6FR26uwfd4g6iw+G52Xr a+f9olIFwrnYa7y+ipMKc/EBjZKXYWAzX1Rr5eLp9GyKGav2jHwe5s3WQXeYMbpJE0Mi b/Ueg1+yaKHjzJ2Km7yHfrufxnL3f7HqVJHiDdncZp9hbRcNlWbQZqfc8uDVhfYvW/D2 QfhQ== X-Gm-Message-State: AGi0PuYwYCp9E69+HwiNCOxBPA+zdYYc+RiqlvcYeILYzj+P1EBO09s3 hpJ9aBfwlNknCZ/e4ko5N8w= X-Google-Smtp-Source: APiQypJ8+z2d/tbIVisTDIJOW12hGb84xkYG5Q+TvvdKi3d8H64/yGWbztz8UPvj/YRBSc0Z2kFJRg== X-Received: by 2002:a17:90b:1989:: with SMTP id mv9mr1147373pjb.70.1587083921013; Thu, 16 Apr 2020 17:38:41 -0700 (PDT) Received: from google.com ([2601:647:4001:3000::50e3]) by smtp.gmail.com with ESMTPSA id gv7sm382543pjb.16.2020.04.16.17.38.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Apr 2020 17:38:39 -0700 (PDT) Date: Thu, 16 Apr 2020 17:38:37 -0700 From: Minchan Kim To: Jaewon Kim , Johannes Weiner Cc: mgorman@suse.de, m.szyprowski@samsung.com, mina86@mina86.com, riel@redhat.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, jaewon31.kim@gmail.com, ytk.lee@samsung.com Subject: Re: [PATCH] mm/vmscan: skip layzfree page on reclaim_clean_pages_from_list Message-ID: <20200417003837.GA90471@google.com> References: <20200416033514.6366-1-jaewon31.kim@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200416033514.6366-1-jaewon31.kim@samsung.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jaewon, On Thu, Apr 16, 2020 at 12:35:14PM +0900, Jaewon Kim wrote: > This patch fix nr_isolate_* mismatch problem between cma and dirty > lazyfree page. > > If try_to_unmap_one is used for reclaim and it detects a dirty lazyfree > page, then the lazyfree page is changed to a normal anon page having > SwapBacked by commit 18863d3a3f59 ("mm: remove SWAP_DIRTY in ttu"). Even > with the change, reclaim context correctly counts isolated files because > it uses is_file_lru to distinguish file. And the change to anon is not > happened if try_to_unmap_one is used for migration. So migration context > like compaction also correctly counts isolated files even though it uses > page_is_file_lru insted of is_file_lru. Recently page_is_file_cache was > renamed to page_is_file_lru by commit 9de4f22a60f7 ("mm: code cleanup for > MADV_FREE"). > > But the nr_isolate_* mismatch problem happens on cma alloc. There is > reclaim_clean_pages_from_list which is being used only by cma. It was > introduced by commit 02c6de8d757c ("mm: cma: discard clean pages during > contiguous allocation instead of migration") to reclaim clean file pages > without migration. The cma alloc uses both reclaim_clean_pages_from_list > and migrate_pages, and it uses page_is_file_lru to count isolated > files. If there are dirty lazyfree pages allocated from cma memory > region, the pages are counted as isolated file at the beginging but are > counted as isolated anon after finished. > > Mem-Info: > Node 0 active_anon:3045904kB inactive_anon:611448kB active_file:14892kB inactive_file:205636kB unevictable:10416kB isolated(anon):0kB isolated(file):37664kB mapped:630216kB dirty:384kB writeback:0kB shmem:42576kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no > > Like log above, there was too much isolated file, 37664kB, which > triggers too_many_isolated in reclaim when there is no isolated file in > system wide. It could be reproducible by running two programs, doing > MADV_FREE, writing and doing cma alloc, respectively. Although isolated > anon is 0, I found that the internal value of isolated anon was the > negative value of isolated file. > > Fix this by skipping anon pages on reclaim_clean_pages_from_list. The > lazyfree page can be checked by both PageAnon(page) and > page_is_file_lru. But in this case, PageAnon is enough to skip all > anon pages. > > Reported-by: Yong-Taek Lee > Signed-off-by: Jaewon Kim Thanks for the investigation! The thing is MADV_FREEed page since supporting swapless could change his LRU status between reclaim. I am worry about voiding the optimization we have kept in CMA but also don't have good idea, either so I tend to agree with this. Let me Cc Johannes who might have better idea. > --- > mm/vmscan.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index b06868fc4926..9380a18eef5e 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1497,6 +1497,9 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone, > LIST_HEAD(clean_pages); > > list_for_each_entry_safe(page, next, page_list, lru) { > + /* to avoid race with MADV_FREE anon page */ > + if (PageAnon(page)) > + continue; > if (page_is_file_lru(page) && !PageDirty(page) && > !__PageMovable(page) && !PageUnevictable(page)) { > ClearPageActive(page); > -- > 2.13.7 >