From: Jens Axboe <axboe@kernel.dk>
To: dgilbert@interlog.com, yang jun <yangjun.donglife123@gmail.com>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH][SCSI] sr: Remove sr_mutex just like sd_module to optimize multi-drive performance
Date: Tue, 05 Nov 2013 10:03:47 -0700 [thread overview]
Message-ID: <527924F3.7090800@kernel.dk> (raw)
In-Reply-To: <52792039.2020405@interlog.com>
On 11/05/2013 09:43 AM, Douglas Gilbert wrote:
> On 13-11-01 11:46 AM, yang jun wrote:
>> The sr_mutex is not necessary, so we can delete it.
>
> It is ironic that you are removing a mutex that serializes
> the access to various calls in the sr driver at the same
> time we are proposing to add a mutex to the open()
> and release() calls in the sg driver. The sg driver's
> proposed mutex is finer grained than sr_mutex: one per
> device.
>
> My guess would be that splitting sr_mutex out to
> a per device mutex will be safer and get the performance
> gain that you seem to be after.
Agree - the mutex should be retained, but make it per-device instead.
That will fix your original issue as well.
--
Jens Axboe
prev parent reply other threads:[~2013-11-05 17:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-01 15:46 [PATCH][SCSI] sr: Remove sr_mutex just like sd_module to optimize multi-drive performance yang jun
2013-11-05 16:43 ` Douglas Gilbert
2013-11-05 17:03 ` Jens Axboe [this message]
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