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From: Shaohua Li <shli@kernel.org>
To: Kent Overstreet <kmo@daterainc.com>
Cc: linux-kernel@vger.kernel.org, axboe@kernel.dk
Subject: Re: [patch 3/4] percpu_ida: add an API to return free tags
Date: Sat, 12 Oct 2013 09:02:39 +0800	[thread overview]
Message-ID: <20131012010239.GC17666@kernel.org> (raw)
In-Reply-To: <20131011203536.GJ28572@kmo>

On Fri, Oct 11, 2013 at 01:35:36PM -0700, Kent Overstreet wrote:
> On Fri, Oct 11, 2013 at 03:18:05PM +0800, Shaohua Li wrote:
> > add an API to return free tags, blk-mq-tag will use it
> 
> Can you explain how this is going to be used? Seems like something that
> could be prone to misuse, try and convince me there isn't a better way
> to do what it's for.

There are two usages. One is for sysfs info output, which can be used for
diagnosis. The other one is blk-mq wants to determine if it's possible a
request can be queued. Neither requires precise data. Yes, caller should be
aware returned data isn't very precise.

Thanks,
Shaohua

  reply	other threads:[~2013-10-12  1:02 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-11  7:18 [patch 0/4] blk-mq: use percpu_ida to manage tags Shaohua Li
2013-10-11  7:18 ` [patch 1/4] percpu_ida: make percpu_ida percpu size/batch configurable Shaohua Li
2013-10-11 20:31   ` Kent Overstreet
2013-10-12  0:52     ` Shaohua Li
2013-10-11  7:18 ` [patch 2/4] percpu_ida: add percpu_ida_for_each_free Shaohua Li
2013-10-11 20:34   ` Kent Overstreet
2013-10-11  7:18 ` [patch 3/4] percpu_ida: add an API to return free tags Shaohua Li
2013-10-11 20:35   ` Kent Overstreet
2013-10-12  1:02     ` Shaohua Li [this message]
2013-10-11  7:18 ` [patch 4/4] blk-mq: switch to percpu-ida for tag menagement Shaohua Li
2013-10-11 14:28   ` Jens Axboe
2013-10-12  0:49     ` Shaohua Li
2013-10-13 18:26       ` Jens Axboe

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