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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,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 831F9C433DF for ; Tue, 4 Aug 2020 00:56:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9239D206DA for ; Tue, 4 Aug 2020 00:56:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728363AbgHDA4A (ORCPT ); Mon, 3 Aug 2020 20:56:00 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:43584 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726130AbgHDAz7 (ORCPT ); Mon, 3 Aug 2020 20:55:59 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 3580CF61B8946DC49F7E; Tue, 4 Aug 2020 08:55:57 +0800 (CST) Received: from [10.164.122.247] (10.164.122.247) by smtp.huawei.com (10.3.19.206) with Microsoft SMTP Server (TLS) id 14.3.487.0; Tue, 4 Aug 2020 08:55:55 +0800 Subject: Re: [f2fs-dev] [PATCH] f2fs: remove a waiter for checkpoint completion To: Jaegeuk Kim , , , CC: Eric Biggers References: <20200803172825.4077289-1-jaegeuk@kernel.org> From: Chao Yu Message-ID: <9638d2c5-cfd0-359f-187a-8e23bc6d822d@huawei.com> Date: Tue, 4 Aug 2020 08:55:55 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200803172825.4077289-1-jaegeuk@kernel.org> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.164.122.247] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/8/4 1:28, Jaegeuk Kim wrote: > It doesn't need to wait for checkpoint being completed triggered by end_io. > > [ 20.157753] ------------[ cut here ]------------ > [ 20.158393] do not call blocking ops when !TASK_RUNNING; state=2 set at [<0000000096354225>] prepare_to_wait+0xcd/0x430 > [ 20.159858] WARNING: CPU: 1 PID: 1152 at kernel/sched/core.c:7142 __might_sleep+0x149/0x1a0 > ... > [ 20.176110] __submit_merged_write_cond+0x191/0x310 > [ 20.176739] f2fs_submit_merged_write+0x18/0x20 > [ 20.177323] f2fs_wait_on_all_pages+0x269/0x2d0 > [ 20.177899] ? block_operations+0x980/0x980 > [ 20.178441] ? __kasan_check_read+0x11/0x20 > [ 20.178975] ? finish_wait+0x260/0x260 > [ 20.179488] ? percpu_counter_set+0x147/0x230 > [ 20.180049] do_checkpoint+0x1757/0x2a50 > [ 20.180558] f2fs_write_checkpoint+0x840/0xaf0 > [ 20.181126] f2fs_sync_fs+0x287/0x4a0 > > Reported-by: Eric Biggers > Signed-off-by: Jaegeuk Kim > --- > fs/f2fs/checkpoint.c | 6 +----- > fs/f2fs/data.c | 4 ---- > fs/f2fs/f2fs.h | 1 - > fs/f2fs/super.c | 1 - > 4 files changed, 1 insertion(+), 11 deletions(-) > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > index 99c8061da55b9..2bdddc725e677 100644 > --- a/fs/f2fs/checkpoint.c > +++ b/fs/f2fs/checkpoint.c > @@ -1255,11 +1255,7 @@ static void unblock_operations(struct f2fs_sb_info *sbi) > > void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type) > { > - DEFINE_WAIT(wait); > - > for (;;) { > - prepare_to_wait(&sbi->cp_wait, &wait, TASK_UNINTERRUPTIBLE); Wouldn't that case high cpu usage before io end? > - > if (!get_pages(sbi, type)) > break; > > @@ -1271,9 +1267,9 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type) > FS_CP_META_IO); > else if (type == F2FS_WB_CP_DATA) > f2fs_submit_merged_write(sbi, DATA); > + > io_schedule_timeout(DEFAULT_IO_TIMEOUT); > } > - finish_wait(&sbi->cp_wait, &wait); > } > > static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc) > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index c1b676be67b9a..588d2871bbe69 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -383,10 +383,6 @@ static void f2fs_write_end_io(struct bio *bio) > clear_cold_data(page); > end_page_writeback(page); > } > - if (!get_pages(sbi, F2FS_WB_CP_DATA) && > - wq_has_sleeper(&sbi->cp_wait)) > - wake_up(&sbi->cp_wait); > - > bio_put(bio); > } > > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index 02811ce15059b..a036539363030 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -1437,7 +1437,6 @@ struct f2fs_sb_info { > struct rw_semaphore cp_rwsem; /* blocking FS operations */ > struct rw_semaphore node_write; /* locking node writes */ > struct rw_semaphore node_change; /* locking node change */ > - wait_queue_head_t cp_wait; > unsigned long last_time[MAX_TIME]; /* to store time in jiffies */ > long interval_time[MAX_TIME]; /* to store thresholds */ > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index 83bf9a02f83f2..5f4d9abc079d6 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -3540,7 +3540,6 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) > > init_rwsem(&sbi->cp_rwsem); > init_rwsem(&sbi->quota_sem); > - init_waitqueue_head(&sbi->cp_wait); > init_sb_info(sbi); > > err = init_percpu_info(sbi); >