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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B32ABC4332F for ; Thu, 14 Dec 2023 01:34:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 23E4B6B03F2; Wed, 13 Dec 2023 20:34:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1EDA58D0083; Wed, 13 Dec 2023 20:34:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 08D526B03F6; Wed, 13 Dec 2023 20:34:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id E1A466B03F2 for ; Wed, 13 Dec 2023 20:34:51 -0500 (EST) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id AED311203BD for ; Thu, 14 Dec 2023 01:34:51 +0000 (UTC) X-FDA: 81563704782.29.E4DBD7E Received: from mail-vs1-f46.google.com (mail-vs1-f46.google.com [209.85.217.46]) by imf08.hostedemail.com (Postfix) with ESMTP id E7B3E160018 for ; Thu, 14 Dec 2023 01:34:48 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=D7ydvEQE; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf08.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.217.46 as permitted sender) smtp.mailfrom=21cnbao@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1702517688; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=TSsCOpQm4rGOZ8dJ8rCuCLQhoSFk4i+8PcfnNmU+diM=; b=UyCDgVShisjxCAeTTv6tD9ifaLiKjPC4evZKmqYGoyQ84cpIKcv3to2SXtE7+8OqcT7mC6 Lo+UTCYArjhqGiNCsSw8Q2xuxU+08rRNnmb80a8qApn3kud611ss0ra7uy4sj3YEtjZprt z3lR3FNIhA6LruSMuarGZodhkrZJwhY= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=D7ydvEQE; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf08.hostedemail.com: domain of 21cnbao@gmail.com designates 209.85.217.46 as permitted sender) smtp.mailfrom=21cnbao@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1702517689; a=rsa-sha256; cv=none; b=dg3kiCqROgUucjuPodq9JwZko2IxiHQR8mnY4FJQFMeWKEg5h8+uS1yqnAOJplTeGGDtbh lCjpx7gDeGd53H8geyX99AUCw1udEkGgqR2lU5QSH+debsnn4o2NI4pUUASL4TaOJOiaL5 TMYf7SswcCXXRIANOFWlVvHKNMld+7w= Received: by mail-vs1-f46.google.com with SMTP id ada2fe7eead31-462e70f1c20so2300474137.0 for ; Wed, 13 Dec 2023 17:34:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702517688; x=1703122488; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=TSsCOpQm4rGOZ8dJ8rCuCLQhoSFk4i+8PcfnNmU+diM=; b=D7ydvEQEWcKZZOqdiNBvo8N1OfIEgJD+8+2i5ZDi3DcYEMuGL/8EQTPsR62R9oGTjP l+I2CpYg9L0EGptsU4nW/fwzC68Cow7FI9mzIgH8UNbg9bcdaKJamXsBIjnq9RTjQsF1 FdvVamxeJB7mpWj6/s7CcVS/r8EkxmwztH+53TrOn//zhbLjPR67F7+gEoB5216e0fkl 62PgS7Gd/2mfCNPp+Ly8Vgqj2RcGada0n/YPJ8PzBOGAVfTOkkc9HRW5FCexsFPSwKW2 DuMxBZHFPajLo6pvI05fLQgIGbpX1B8TvIjUHnwYXEerSZo733j8/eoQGm9LfPrcBBSL Y46w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702517688; x=1703122488; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=TSsCOpQm4rGOZ8dJ8rCuCLQhoSFk4i+8PcfnNmU+diM=; b=R0enF1IHMzEfo1RbN6IjdDktzbt7sjFAEOjj95FlReao9RActbtfzinI0QvUpLTqvr z8dAaU8gztiIbdYQWGuYzGaBQNauoTaDNTwOQ7puN418MNi1JSqHIrBFK/DHcUqtWvtn UmGvX+U03RJjcgwLRsqEvfbTiiyh7q3PKMrblwVI0qCoogz+gzJtYlo2+CvpmysBbpJg 8xXTX33t8ltZus4coven3VYkKJ/CJFzHSyA6zt39mNkFH8vl9OEcGC1dGSeBUBo3IKY2 GvtFTwnbF4+mCkqDEc+6FNuI5VTRFAP76tDZinufp7vvC1YgDTqPF99pn8i0Jb+VJ5MH W/HA== X-Gm-Message-State: AOJu0YyxrGA93ZO2OmjDq7IKNit/LmVg6v7IWQkF80UgncdKVoX/Z7hv vZ4Hq3qxgfr/7rXM3WXOmktPETvSVIBPBYr/Zqg= X-Google-Smtp-Source: AGHT+IF0f58ox2Go0izpph3/lXGL4DIhmtGxUOksIbF/sfhoXjAlpoo4updml0aSDurDx2cMNZkFHMEg0hoBHZDOyM0= X-Received: by 2002:a05:6102:38c7:b0:464:7eeb:107f with SMTP id k7-20020a05610238c700b004647eeb107fmr6796687vst.12.1702517687951; Wed, 13 Dec 2023 17:34:47 -0800 (PST) MIME-Version: 1.0 References: <20231206110054.61617-1-v-songbaohua@oppo.com> <20231213130231.ksban2ovad4q4rxj@techsingularity.net> In-Reply-To: <20231213130231.ksban2ovad4q4rxj@techsingularity.net> From: Barry Song <21cnbao@gmail.com> Date: Thu, 14 Dec 2023 09:34:35 +0800 Message-ID: Subject: Re: [PATCH] mm: compaction: avoid fast_isolate_freepages blindly choose improper pageblock To: Mel Gorman , akpm@linux-foundation.org Cc: baolin.wang@linux.alibaba.com, linux-mm@kvack.org, david@redhat.com, hannes@cmpxchg.org, huzhanyuan@oppo.com, linux-kernel@vger.kernel.org, shikemeng@huaweicloud.com, v-songbaohua@oppo.com, willy@infradead.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: E7B3E160018 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: 9u76xfruh7bu9iyxmdpne6wu6wtuo8pp X-HE-Tag: 1702517688-102480 X-HE-Meta: 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 Pc98QPzH 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Dec 13, 2023 at 9:02=E2=80=AFPM Mel Gorman wrote: > > On Thu, Dec 07, 2023 at 12:00:54AM +1300, Barry Song wrote: > > Testing shows fast_isolate_freepages can blindly choose an unsuitable > > pageblock from time to time particularly while the min mark is used > > from XXX path: > > if (!page) { > > cc->fast_search_fail++; > > if (scan_start) { > > /* > > * Use the highest PFN found above min. If one was > > * not found, be pessimistic for direct compaction > > * and use the min mark. > > */ > > if (highest >=3D min_pfn) { > > page =3D pfn_to_page(highest); > > cc->free_pfn =3D highest; > > } else { > > if (cc->direct_compaction && pfn_valid(min_pfn= )) { /* XXX */ > > page =3D pageblock_pfn_to_page(min_pfn= , > > min(pageblock_end_pfn(min_pfn)= , > > zone_end_pfn(cc->zone)), > > cc->zone); > > cc->free_pfn =3D min_pfn; > > } > > } > > } > > } > > > > The reason is that no code is doing any check on the min_pfn > > min_pfn =3D pageblock_start_pfn(cc->free_pfn - (distance >> 1)); > > > > In contrast, slow path of isolate_freepages() is always skipping unsuit= able > > pageblocks in a decent way. > > > > This issue doesn't happen quite often. When running 25 machines with 16= GiB > > memory for one night, most of them can hit this unexpected code path. > > However the frequency isn't like many times per second. It might be one > > time in a couple of hours. Thus, it is very hard to measure the visible > > performance impact in my machines though the affection of choosing the > > unsuitable migration_target should be negative in theory. > > > > I feel it's still worth fixing this to at least make the code theoretic= ally > > self-explanatory as it is quite odd an unsuitable migration_target can = be > > still migration_target. > > > > Reported-by: Zhanyuan Hu > > Signed-off-by: Barry Song > > Acked-by: Mel Gorman Hi Mel, Thanks! Hi Andrew, Given this patch has been in mm-stable, https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?h=3Dmm-= stable&id=3Dd19b1a1797 does it still have a chance to collect Mel's tag=EF=BC=9F > > -- > Mel Gorman > SUSE Labs Thanks Barry