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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B39BCECAAD4 for ; Sat, 3 Sep 2022 06:07:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232032AbiICGHK (ORCPT ); Sat, 3 Sep 2022 02:07:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231643AbiICGHJ (ORCPT ); Sat, 3 Sep 2022 02:07:09 -0400 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 83AFADC09A; Fri, 2 Sep 2022 23:07:07 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4MKPQn1wFgzl3xd; Sat, 3 Sep 2022 14:05:37 +0800 (CST) Received: from [10.174.176.73] (unknown [10.174.176.73]) by APP2 (Coremail) with SMTP id Syh0CgAnenMH7xJjzRo3AQ--.49859S3; Sat, 03 Sep 2022 14:07:05 +0800 (CST) Subject: Re: [PATCH -next 2/3] md/raid10: convert resync_lock to use seqlock To: Logan Gunthorpe , Yu Kuai , song@kernel.org Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, "yukuai (C)" References: <20220829131502.165356-1-yukuai1@huaweicloud.com> <20220829131502.165356-3-yukuai1@huaweicloud.com> <04128618-962f-fd4e-64a9-09ecf7f83776@deltatee.com> <3d07a8fd-3b5e-dc68-4c32-6c0dcd0c1264@huaweicloud.com> <04571bb7-10b3-e841-a975-d9b6e0305e8a@deltatee.com> From: Yu Kuai Message-ID: <8dd81e04-0041-63a4-e16f-f92dd8c4930e@huaweicloud.com> Date: Sat, 3 Sep 2022 14:07:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <04571bb7-10b3-e841-a975-d9b6e0305e8a@deltatee.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID: Syh0CgAnenMH7xJjzRo3AQ--.49859S3 X-Coremail-Antispam: 1UD129KBjvJXoWxXw4fKF1rAF4DCr43KFW8Crg_yoWrXry8p3 ySqr15tFWUtF90qw1Dta1j9F1Fgw4kKF9rGFZ5Wa1kZFsYqryfJFy3GryrKryqvr93AFy8 Xa98GrZ3Gw1UtFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkG14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcVAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCYjI0SjxkI62AI1cAE67vI Y487MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI 0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUAVWUtwCIc40Y 0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxV WUJVW8JwCI42IY6xAIw20EY4v20xvaj40_WFyUJVCq3wCI42IY6I8E87Iv67AKxVWUJVW8 JwCI42IY6I8E87Iv6xkF7I0E14v26r1j6r4UYxBIdaVFxhVjvjDU0xZFpf9x0JUdHUDUUU UU= X-CM-SenderInfo: 51xn3trlr6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org Hi, 在 2022/09/03 1:03, Logan Gunthorpe 写道: > > > > On 2022-09-02 02:14, Yu Kuai wrote: >> Can you try the following patch? I'm running mdadm tests myself and I >> didn't see any problems yet. > > Yes, that patch seems to fix the issue. > > However, may I suggest we do this without trying to introduce new > helpers into wait.h? I suspect that could result in a fair amount of > bike shedding and delay. wait_event_cmd() is often used in situations > where a specific lock type doesn't have a helper. Yes, that sounds good. > > My stab at it is in a diff below which also fixes the bug. > > I'd also recommend somebody clean up that nasty condition in > wait_barrier(). Put it into an appropriately named function > with some comments. As is, it is pretty much unreadable. Now we're at it, I can take a look. Thanks, Kuai > > Logan > > -- > > > diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c > index 0e3229ee1ebc..ae297bc870bd 100644 > --- a/drivers/md/raid10.c > +++ b/drivers/md/raid10.c > @@ -934,22 +934,26 @@ static void flush_pending_writes(struct r10conf *conf) > * lower_barrier when the particular background IO completes. > */ > > +#define wait_event_barrier_cmd(conf, cond, cmd) \ > + wait_event_cmd((conf)->wait_barrier, cond, \ > + write_sequnlock_irq(&(conf)->resync_lock); cmd, \ > + write_seqlock_irq(&(conf)->resync_lock)) > +#define wait_event_barrier(conf, cond) wait_event_barrier_cmd(conf, cond, ) > + > static void raise_barrier(struct r10conf *conf, int force) > { > write_seqlock_irq(&conf->resync_lock); > BUG_ON(force && !conf->barrier); > > /* Wait until no block IO is waiting (unless 'force') */ > - wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting, > - conf->resync_lock.lock); > + wait_event_barrier(conf, force || !conf->nr_waiting); > > /* block any new IO from starting */ > WRITE_ONCE(conf->barrier, conf->barrier + 1); > > /* Now wait for all pending IO to complete */ > - wait_event_lock_irq(conf->wait_barrier, > - !atomic_read(&conf->nr_pending) && conf->barrier < RESYNC_DEPTH, > - conf->resync_lock.lock); > + wait_event_barrier(conf, !atomic_read(&conf->nr_pending) && > + conf->barrier < RESYNC_DEPTH); > > write_sequnlock_irq(&conf->resync_lock); > } > @@ -1007,20 +1011,19 @@ static bool wait_barrier(struct r10conf *conf, bool nowait) > ret = false; > } else { > raid10_log(conf->mddev, "wait barrier"); > - wait_event_lock_irq(conf->wait_barrier, > - !conf->barrier || > - (atomic_read(&conf->nr_pending) && > - bio_list && > - (!bio_list_empty(&bio_list[0]) || > - !bio_list_empty(&bio_list[1]))) || > + wait_event_barrier(conf, > + !conf->barrier || > + (atomic_read(&conf->nr_pending) && > + bio_list && > + (!bio_list_empty(&bio_list[0]) || > + !bio_list_empty(&bio_list[1]))) || > /* move on if recovery thread is > * blocked by us > */ > - (conf->mddev->thread->tsk == current && > - test_bit(MD_RECOVERY_RUNNING, > - &conf->mddev->recovery) && > - conf->nr_queued > 0), > - conf->resync_lock.lock); > + (conf->mddev->thread->tsk == current && > + test_bit(MD_RECOVERY_RUNNING, > + &conf->mddev->recovery) && > + conf->nr_queued > 0)); > } > conf->nr_waiting--; > if (!conf->nr_waiting) > @@ -1058,10 +1061,9 @@ static void freeze_array(struct r10conf *conf, int extra) > conf->array_freeze_pending++; > WRITE_ONCE(conf->barrier, conf->barrier + 1); > conf->nr_waiting++; > - wait_event_lock_irq_cmd(conf->wait_barrier, > - atomic_read(&conf->nr_pending) == conf->nr_queued+extra, > - conf->resync_lock.lock, > - flush_pending_writes(conf)); > + wait_event_barrier_cmd(conf, > + atomic_read(&conf->nr_pending) == conf->nr_queued+extra, > + flush_pending_writes(conf)); > > conf->array_freeze_pending--; > write_sequnlock_irq(&conf->resync_lock); > . >