From:   Jens Axboe <axboe@kernel.dk>
To:     Laibin Qiu <qiulaibin@huawei.com>, ming.lei@redhat.com,
        john.garry@huawei.com
Cc:     akpm@linux-foundation.org, bvanassche@acm.org,
        linux-kernel@vger.kernel.org, hare@suse.de,
        linux-block@vger.kernel.org, andriy.shevchenko@linux.intel.com,
        martin.petersen@oracle.com
In-Reply-To: <20220113025536.1479653-1-qiulaibin@huawei.com>
References: <20220113025536.1479653-1-qiulaibin@huawei.com>
Subject: Re: [PATCH -next V5] blk-mq: fix tag_get wait task can't be awakened
Message-Id: <164210355584.171739.7914692743898015276.b4-ty@kernel.dk>
Date:   Thu, 13 Jan 2022 12:52:35 -0700
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
Precedence: bulk

On Thu, 13 Jan 2022 10:55:36 +0800, Laibin Qiu wrote:
> In case of shared tags, there might be more than one hctx which
> allocates from the same tags, and each hctx is limited to allocate at
> most:
>         hctx_max_depth = max((bt->sb.depth + users - 1) / users, 4U);
> 
> tag idle detection is lazy, and may be delayed for 30sec, so there
> could be just one real active hctx(queue) but all others are actually
> idle and still accounted as active because of the lazy idle detection.
> Then if wake_batch is > hctx_max_depth, driver tag allocation may wait
> forever on this real active hctx.
> 
> [...]

Applied, thanks!

[1/1] blk-mq: fix tag_get wait task can't be awakened
      commit: 180dccb0dba4f5e84a4a70c1be1d34cbb6528b32

Best regards,
-- 
Jens Axboe