Received: by 2002:a05:6a10:8c0a:0:0:0:0 with SMTP id go10csp233583pxb; Sat, 20 Feb 2021 01:40:36 -0800 (PST) X-Google-Smtp-Source: ABdhPJxKySNb8XYLvSq4RGAOU+eFhT+flnBUuNdz9VWxa0uI6ulIrpz2JGH4lHhNla1oLUBcta4B X-Received: by 2002:a17:906:5495:: with SMTP id r21mr12738433ejo.59.1613814035808; Sat, 20 Feb 2021 01:40:35 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1613814035; cv=none; d=google.com; s=arc-20160816; b=HtRqh08jyqlwlbPwVRUA9QiyOwKF0wt0ke9YOdnSjEsVxIPTjF9LRYPt3LPdeg9OIQ H+F0JulH8/867iesuJ/1ShlRfLKxKt/LzhAzCNb9R8NUtdQq5EQ29jn7/UBth+XM5k1s ZSxSV1Z2JfZyWrYay4dnVzngDdf9VkvucZiqB4+Fiz1qEJVs+2c486WrqQI8XeF98qTi U+n4LkUiw3jNp4OmvJ3h0foQ+3ij95zj4I3wMeRaMbfIBO8RtmQoVoZA5va8rL69CV/I uhmHqFRMkMLICkfKjnsWqbXEC/oTpllkQ3QyXG5ET0hLqWA/5Ar5el6/gh0LTN6jmvAF /74w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=/v0cwuG0ILIPLuSAOt1BSoLx/Db5cQkrAQlWGSva2Qs=; b=tvgzII20H07Tj99qWgg8Z0HzueTheyge2cZD396Y19SfNT3CH+LQ4GVHeOHzVEGFVB OOW7kXFlZ6k6iJ4O+XZh28jmAZ7KSs8IdmFhNPd7xPXVLUjN+Rulacn4lo9HEpmPM2x3 ibR+QroPBD7nvXSwHb5gSV+TW/HWqeQk6KGho75/LyTdHZxrTIzoqu0uwrekVHBhjnfN oAv+yD7SwgiO2mh+YVb02ZK4RPKLLAw7gfew8eGLGfjiJzEmTzcbDw4Ea+vpOJbZ/dvS d03rzQxx9rKD/N6Q8bR553VRwobdjc7ftPJebAXVL+z6Kudz5KTMdT6nm4dAxZyVTPdZ T6Bw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id hk1si8063261ejb.67.2021.02.20.01.40.13; Sat, 20 Feb 2021 01:40:35 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229789AbhBTJjn (ORCPT + 99 others); Sat, 20 Feb 2021 04:39:43 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:12628 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229476AbhBTJji (ORCPT ); Sat, 20 Feb 2021 04:39:38 -0500 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DjNdc0V3Dz1695F; Sat, 20 Feb 2021 17:37:24 +0800 (CST) Received: from szvp000203569.huawei.com (10.120.216.130) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.498.0; Sat, 20 Feb 2021 17:38:46 +0800 From: Chao Yu To: CC: , , , Chao Yu Subject: [PATCH 3/3] f2fs: update comments for explicit memory barrier Date: Sat, 20 Feb 2021 17:38:43 +0800 Message-ID: <20210220093843.64379-3-yuchao0@huawei.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210220093843.64379-1-yuchao0@huawei.com> References: <20210220093843.64379-1-yuchao0@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.120.216.130] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add more detailed comments for explicit memory barrier used by f2fs, in order to enhance code readability. Signed-off-by: Chao Yu --- fs/f2fs/checkpoint.c | 6 +++++- fs/f2fs/segment.c | 6 +++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c index 174a0819ad96..c75866cd72fa 100644 --- a/fs/f2fs/checkpoint.c +++ b/fs/f2fs/checkpoint.c @@ -1818,7 +1818,11 @@ int f2fs_issue_checkpoint(struct f2fs_sb_info *sbi) llist_add(&req.llnode, &cprc->issue_list); atomic_inc(&cprc->queued_ckpt); - /* update issue_list before we wake up issue_checkpoint thread */ + /* + * update issue_list before we wake up issue_checkpoint thread, + * this smp_mb() pairs with another barrier in ___wait_event(), + * see more details in comments of waitqueue_active(). + */ smp_mb(); if (waitqueue_active(&cprc->ckpt_wait_queue)) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 2190910c68b0..2d5a82c4ca15 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -663,7 +663,11 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi, nid_t ino) llist_add(&cmd.llnode, &fcc->issue_list); - /* update issue_list before we wake up issue_flush thread */ + /* + * update issue_list before we wake up issue_flush thread, this + * smp_mb() pairs with another barrier in ___wait_event(), see + * more details in comments of waitqueue_active(). + */ smp_mb(); if (waitqueue_active(&fcc->flush_wait_queue)) -- 2.29.2