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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 15B4BC47096 for ; Thu, 3 Jun 2021 08:46:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBD77613E3 for ; Thu, 3 Jun 2021 08:46:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229849AbhFCIs0 (ORCPT ); Thu, 3 Jun 2021 04:48:26 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:45466 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229486AbhFCIsZ (ORCPT ); Thu, 3 Jun 2021 04:48:25 -0400 Received: from relay2.suse.de (unknown [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 4F6D8219E1; Thu, 3 Jun 2021 08:46:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1622710000; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZGYew5SGmdoU7MaUMjCQJu6CUQQRyZgDm/ugr7FJkik=; b=UPdBAscVGcKfIB7r1rdiArP5E4b1W4s6cD6RmUVdMU5EgYQRCbmCPX7Qkx+g1xCdv/3Rdi DHnBiT88YrNR5y8rcINSabGbteTumqIaq9E3RRuJ6ahND8FbdUOgIS/PT2NnG8ZwaJDVrx Y57qWHI1PWHfiAByh8IrKX8SDb9DVv4= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1622710000; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZGYew5SGmdoU7MaUMjCQJu6CUQQRyZgDm/ugr7FJkik=; b=8rGAUYu9J4Ro+7/kzBAGvQIRAbyD6+G0cvtEO8GNulsXy0sRHYzt0/SPREI5C17fltgMAS ktPOPIOwHMbo7CCg== Received: from quack2.suse.cz (unknown [10.100.200.198]) by relay2.suse.de (Postfix) with ESMTP id 26201A3B90; Thu, 3 Jun 2021 08:46:40 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id EAABE1F2C98; Thu, 3 Jun 2021 10:46:39 +0200 (CEST) Date: Thu, 3 Jun 2021 10:46:39 +0200 From: Jan Kara To: Roman Gushchin Cc: Jan Kara , Tejun Heo , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Alexander Viro , Dennis Zhou , Dave Chinner , cgroups@vger.kernel.org Subject: Re: [PATCH v6 1/5] writeback, cgroup: switch to rcu_work API in inode_switch_wbs() Message-ID: <20210603084639.GD23647@quack2.suse.cz> References: <20210603005517.1403689-1-guro@fb.com> <20210603005517.1403689-2-guro@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210603005517.1403689-2-guro@fb.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed 02-06-21 17:55:13, Roman Gushchin wrote: > Inode's wb switching requires two steps divided by an RCU grace > period. It's currently implemented as an RCU callback > inode_switch_wbs_rcu_fn(), which schedules inode_switch_wbs_work_fn() > as a work. > > Switching to the rcu_work API allows to do the same in a cleaner and > slightly shorter form. > > Signed-off-by: Roman Gushchin Looks good to me. You can add: Reviewed-by: Jan Kara Honza > --- > fs/fs-writeback.c | 18 ++++-------------- > 1 file changed, 4 insertions(+), 14 deletions(-) > > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c > index e91980f49388..1f51857e41d1 100644 > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -335,8 +335,7 @@ struct inode_switch_wbs_context { > struct inode *inode; > struct bdi_writeback *new_wb; > > - struct rcu_head rcu_head; > - struct work_struct work; > + struct rcu_work work; > }; > > static void bdi_down_write_wb_switch_rwsem(struct backing_dev_info *bdi) > @@ -352,7 +351,7 @@ static void bdi_up_write_wb_switch_rwsem(struct backing_dev_info *bdi) > static void inode_switch_wbs_work_fn(struct work_struct *work) > { > struct inode_switch_wbs_context *isw = > - container_of(work, struct inode_switch_wbs_context, work); > + container_of(to_rcu_work(work), struct inode_switch_wbs_context, work); > struct inode *inode = isw->inode; > struct backing_dev_info *bdi = inode_to_bdi(inode); > struct address_space *mapping = inode->i_mapping; > @@ -469,16 +468,6 @@ static void inode_switch_wbs_work_fn(struct work_struct *work) > atomic_dec(&isw_nr_in_flight); > } > > -static void inode_switch_wbs_rcu_fn(struct rcu_head *rcu_head) > -{ > - struct inode_switch_wbs_context *isw = container_of(rcu_head, > - struct inode_switch_wbs_context, rcu_head); > - > - /* needs to grab bh-unsafe locks, bounce to work item */ > - INIT_WORK(&isw->work, inode_switch_wbs_work_fn); > - queue_work(isw_wq, &isw->work); > -} > - > /** > * inode_switch_wbs - change the wb association of an inode > * @inode: target inode > @@ -534,7 +523,8 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id) > * lock so that stat transfer can synchronize against them. > * Let's continue after I_WB_SWITCH is guaranteed to be visible. > */ > - call_rcu(&isw->rcu_head, inode_switch_wbs_rcu_fn); > + INIT_RCU_WORK(&isw->work, inode_switch_wbs_work_fn); > + queue_rcu_work(isw_wq, &isw->work); > > atomic_inc(&isw_nr_in_flight); > return; > -- > 2.31.1 > -- Jan Kara SUSE Labs, CR