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 77172C433F5 for ; Wed, 30 Mar 2022 08:13:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B1DC88D0003; Wed, 30 Mar 2022 04:13:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ACB848D0001; Wed, 30 Mar 2022 04:13:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9BB828D0003; Wed, 30 Mar 2022 04:13:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0144.hostedemail.com [216.40.44.144]) by kanga.kvack.org (Postfix) with ESMTP id 88BDB8D0001 for ; Wed, 30 Mar 2022 04:13:44 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 3E7FC8249980 for ; Wed, 30 Mar 2022 08:13:44 +0000 (UTC) X-FDA: 79300338768.28.43538F7 Received: from mail-yw1-f181.google.com (mail-yw1-f181.google.com [209.85.128.181]) by imf18.hostedemail.com (Postfix) with ESMTP id 0D7CF1C000B for ; Wed, 30 Mar 2022 08:13:42 +0000 (UTC) Received: by mail-yw1-f181.google.com with SMTP id 00721157ae682-2e68c95e0f9so210006887b3.0 for ; Wed, 30 Mar 2022 01:13:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=+K2owB2t+DyQbJlqnNOc4HsIBOKgjIwr1F8eYT47SAY=; b=L96kVudZpRgDc4Yt/oIj1RBcCzRw1KG7XKih3MPhLDooTQIKsvMLOgba9DqIS7VT07 i4R0x5C4/4WgR3f+71vyARmUNbV1X8MrQwH7vZDAbuiOkJ58nn8sJWMh+pjzrSi1fETb fgEnPXL3fulDjgZZTsMToe2KPEYW61H2nE8khMJCRkOAaoxo6JWffKcRkzGh9v8vAbo1 jGWK/HQ6Pin99Av4aobNB/qcyVS4zArGtL632WFz+l7f4QBuofP/hlL7Nn0s2gPZnAey g96bM2S+sEcj5HkPkUXv28NMphmtAFYK/X1mfGGdRibmJetHul+LW3fefsdAOjGYwcdv bb4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=+K2owB2t+DyQbJlqnNOc4HsIBOKgjIwr1F8eYT47SAY=; b=Hx+yYx2qROcgLhL2jR1p/M1KrBlRfOSpKndeLAsCdRJ63TVrECY4mmQqTk//cgJSf0 2Pu2b0uwdKl8j1Lt6lihTRBFueo8ACgx+/r+tf+xaGUW8rUgzsCPAYwMpK4My/7mdQVd 1qbn/Wd95I7R+Ekz7wl+OpVbP/qU+KmGP521ez8xCpgeoj+FzTZNnsUNAXFSNPc5RLVP Qd/NLscR0TUCN8JIyMoadedQ2HDtzvlSVDejZb2oqDvydpHGV65H4R7d/bQCrw2whQdb F4Upcv4FZCMU3FQzkcuoT8900kes5LPNNiOfCfQHiCUguSKfCdZ5oKWO1m3cGBTOYWdP fpHA== X-Gm-Message-State: AOAM531NUjVT7JzdaP6jL4IrCL0uwqpUm/hWfx8VC/EfJqNKaO8rJ6pI 1tFLderjfZ+9dO7QhNebVf5xvjKMkm+4nOiEupp+kQ== X-Google-Smtp-Source: ABdhPJyiJphZ0B4bNrtTJ592K7nKM80aJvrFgk7oeKtVKWMl4n3G2wQRnpMTonCi/3gEv7I+n3WHJrN2/z+CI9JQTU8= X-Received: by 2002:a81:897:0:b0:2e5:f3b2:f6de with SMTP id 145-20020a810897000000b002e5f3b2f6demr35424504ywi.141.1648628022097; Wed, 30 Mar 2022 01:13:42 -0700 (PDT) MIME-Version: 1.0 References: <20220329132619.18689-1-linmiaohe@huawei.com> <20220329132619.18689-2-linmiaohe@huawei.com> In-Reply-To: <20220329132619.18689-2-linmiaohe@huawei.com> From: Muchun Song Date: Wed, 30 Mar 2022 16:13:06 +0800 Message-ID: Subject: Re: [PATCH 1/8] mm/vmscan: remove redundant folio_test_swapbacked check when folio is file lru To: Miaohe Lin Cc: Andrew Morton , Linux Memory Management List , LKML Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=L96kVudZ; spf=pass (imf18.hostedemail.com: domain of songmuchun@bytedance.com designates 209.85.128.181 as permitted sender) smtp.mailfrom=songmuchun@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com X-Stat-Signature: 9mraiocn4d77ou8xwot8uchw891rrtjg X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 0D7CF1C000B X-HE-Tag: 1648628022-546179 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: On Tue, Mar 29, 2022 at 9:26 PM Miaohe Lin wrote: > > When folio is file lru, folio_test_swapbacked is guaranteed to be true. So > it's unnecessary to check it here again. No functional change intended. > > Signed-off-by: Miaohe Lin > --- > mm/vmscan.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 1678802e03e7..7c1a9713bfc9 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1434,8 +1434,7 @@ static void folio_check_dirty_writeback(struct folio *folio, > * Anonymous pages are not handled by flushers and must be written > * from reclaim context. Do not stall reclaim based on them > */ > - if (!folio_is_file_lru(folio) || > - (folio_test_anon(folio) && !folio_test_swapbacked(folio))) { > + if (!folio_is_file_lru(folio) || folio_test_anon(folio)) { At least your login is no problem since folio_is_file_lru() is equal to !folio_test_swapbacked(). But the new code is not clear to me. The old code is easy to understand, e.g. folio_test_anon(folio) && !folio_test_swapbacked(folio) tells us that the anon pages which do not need to be swapped should be skipped. So I'm neutral on the patch.