From: Christoph Hellwig <hch@infradead.org>
To: Merlijn Wajer <merlijn@archive.org>
Cc: merlijn@wizzup.org, linux-scsi@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] scsi: sr: get rid of sr global mutex
Date: Tue, 18 Feb 2020 09:12:59 -0800 [thread overview]
Message-ID: <20200218171259.GA6724@infradead.org> (raw)
In-Reply-To: <20200218143918.30267-1-merlijn@archive.org>
On Tue, Feb 18, 2020 at 03:39:17PM +0100, Merlijn Wajer wrote:
> When replacing the Big Kernel Lock in commit
> 2a48fc0ab24241755dc93bfd4f01d68efab47f5a ("block: autoconvert trivial
> BKL users to private mutex"), the lock was replaced with a sr-wide lock.
>
> This causes very poor performance when using multiple sr devices, as the
> sr driver was not able to execute more than one command to one drive at
> any given time, even when there were many CD drives available.
>
> Replace the global mutex with per-sr-device mutex.
Do we actually need the lock at all? What is protected by it?
next prev parent reply other threads:[~2020-02-18 17:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 14:39 Merlijn Wajer
2020-02-18 17:12 ` Christoph Hellwig [this message]
2020-02-18 17:20 ` James Bottomley
2020-02-18 17:23 ` Christoph Hellwig
2020-02-18 17:28 ` James Bottomley
2020-02-18 17:31 ` Christoph Hellwig
2020-02-18 19:21 ` Merlijn B.W. Wajer
2020-02-18 19:46 ` Arnd Bergmann
2020-02-24 21:20 ` Merlijn B.W. Wajer
[not found] <9d50ecd4-9fd1-6865-5509-a5ef119828df () archive ! org>
2020-03-06 22:43 ` Simon Arlott
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