From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 90A9213D52F; Thu, 31 Jul 2025 06:25:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753943120; cv=none; b=VjUU8tPIW3AUMMesKwxrwVVvXf0M6IKwLYU5q5NfAETUMHH/iaMHjuFpUJ1K5bIgDRvqte9Yi/8eWA/DBdBJv20bVvuUCpo6C9gsUMOzTMaNdGyKGqSUZBpSVyvBOhWH5kZSbpZrhW6AaQWckxs8/yl/gqnsr3MUZ73TS6G2Mkw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753943120; c=relaxed/simple; bh=TGXdtwhmMwtdMwod/G5JzG+S/xDyw/ykF4L+1KvP6Ng=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=RX6rZKkHBPMuDwDKqXHjleqO9iwvXgXEArRYcerELSzUBHWBt+0pbUdFJ+IXUQrOoo3clbpuGvVxi02qXE1t/yj6YGUSJzaNRia7tx7y3B/bxx2QJp4UQpQd5954stKjL/lDQAN7FpPfgzJ95CxwkwN5EpF2Epn6bSoZ3b+L47A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rfr2F0cB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rfr2F0cB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9DE6EC4CEEF; Thu, 31 Jul 2025 06:25:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753943119; bh=TGXdtwhmMwtdMwod/G5JzG+S/xDyw/ykF4L+1KvP6Ng=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=rfr2F0cBLpmc418dGcj8xRdem1fEJ84FufK0tWjbjjtiDAnhudN/XwR+5LfnBMVG2 Z8gl/2ShcK1AJF+h3CRBaSor+XiPmbbzQSM/cmL5/m04emHcx8D07rS1xLV8s2q76L xHYLxeWIN7sQ7VWbUncnYNkdQdYYwWb43b6s3KgFZn7ZXy1MCGn8VfdMvWxFk7EvpS DpY8BCxG5lNGxTzJ3f2YS+4E+Wuu9LLy6GS2B8zd0AH5bnQDsudyIqDahnlHz/hBDp aeYe8K8WiZNQnUx/omkmV6MY/Y5K7w0VWuXho+w4hGntcRwded2ur7xOyJRW0uHZKV f1i45QulP5R/g== Message-ID: <226d1cd7-bd35-4773-8f1c-d03f9c870133@kernel.org> Date: Thu, 31 Jul 2025 15:22:44 +0900 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/5] mq-deadline: switch to use elevator lock To: Hannes Reinecke , Yu Kuai , jack@suse.cz, tj@kernel.org, josef@toxicpanda.com, axboe@kernel.dk, yukuai3@huawei.com Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, johnny.chenyi@huawei.com References: <20250730082207.4031744-1-yukuai1@huaweicloud.com> <20250730082207.4031744-3-yukuai1@huaweicloud.com> <750643e5-9f24-4e4c-8270-e421a03cf463@suse.de> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <750643e5-9f24-4e4c-8270-e421a03cf463@suse.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 7/31/25 3:20 PM, Hannes Reinecke wrote: > On 7/30/25 10:22, Yu Kuai wrote: >> From: Yu Kuai >> >> Replace the internal spinlock 'dd->lock' with the new spinlock in >> elevator_queue, there are no functional changes. >> >> Signed-off-by: Yu Kuai >> --- >>   block/mq-deadline.c | 58 +++++++++++++++++++++------------------------ >>   1 file changed, 27 insertions(+), 31 deletions(-) >> >> diff --git a/block/mq-deadline.c b/block/mq-deadline.c >> index 9ab6c6256695..2054c023e855 100644 >> --- a/block/mq-deadline.c >> +++ b/block/mq-deadline.c >> @@ -101,7 +101,7 @@ struct deadline_data { >>       u32 async_depth; >>       int prio_aging_expire; >>   -    spinlock_t lock; >> +    spinlock_t *lock; >>   }; >>     /* Maps an I/O priority class to a deadline scheduler priority. */ >> @@ -213,7 +213,7 @@ static void dd_merged_requests(struct request_queue *q, >> struct request *req, >>       const u8 ioprio_class = dd_rq_ioclass(next); >>       const enum dd_prio prio = ioprio_class_to_prio[ioprio_class]; >>   -    lockdep_assert_held(&dd->lock); >> +    lockdep_assert_held(dd->lock); >>         dd->per_prio[prio].stats.merged++; >>   @@ -253,7 +253,7 @@ static u32 dd_queued(struct deadline_data *dd, enum >> dd_prio prio) >>   { >>       const struct io_stats_per_prio *stats = &dd->per_prio[prio].stats; >>   -    lockdep_assert_held(&dd->lock); >> +    lockdep_assert_held(dd->lock); >>         return stats->inserted - atomic_read(&stats->completed); >>   } >> @@ -323,7 +323,7 @@ static struct request *__dd_dispatch_request(struct >> deadline_data *dd, >>       enum dd_prio prio; >>       u8 ioprio_class; >>   -    lockdep_assert_held(&dd->lock); >> +    lockdep_assert_held(dd->lock); >>         if (!list_empty(&per_prio->dispatch)) { >>           rq = list_first_entry(&per_prio->dispatch, struct request, >> @@ -434,7 +434,7 @@ static struct request >> *dd_dispatch_prio_aged_requests(struct deadline_data *dd, >>       enum dd_prio prio; >>       int prio_cnt; >>   -    lockdep_assert_held(&dd->lock); >> +    lockdep_assert_held(dd->lock); >>         prio_cnt = !!dd_queued(dd, DD_RT_PRIO) + !!dd_queued(dd, DD_BE_PRIO) + >>              !!dd_queued(dd, DD_IDLE_PRIO); >> @@ -466,10 +466,9 @@ static struct request *dd_dispatch_request(struct >> blk_mq_hw_ctx *hctx) >>       struct request *rq; >>       enum dd_prio prio; >>   -    spin_lock(&dd->lock); >>       rq = dd_dispatch_prio_aged_requests(dd, now); >>       if (rq) >> -        goto unlock; >> +        return rq; >>         /* >>        * Next, dispatch requests in priority order. Ignore lower priority >> @@ -481,9 +480,6 @@ static struct request *dd_dispatch_request(struct >> blk_mq_hw_ctx *hctx) >>               break; >>       } >>   -unlock: >> -    spin_unlock(&dd->lock); >> - >>       return rq; >>   } >>   @@ -538,9 +534,9 @@ static void dd_exit_sched(struct elevator_queue *e) >>           WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_READ])); >>           WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_WRITE])); >>   -        spin_lock(&dd->lock); >> +        spin_lock(dd->lock); >>           queued = dd_queued(dd, prio); >> -        spin_unlock(&dd->lock); >> +        spin_unlock(dd->lock); >>             WARN_ONCE(queued != 0, >>                 "statistics for priority %d: i %u m %u d %u c %u\n", > > Do you still need 'dd->lock'? Can't you just refer to the lock from the > elevator_queue structure directly? Indeed. Little inline helpers for locking/unlocking q->elevator->lock would be nice. -- Damien Le Moal Western Digital Research