Re: [patch 3/4] percpu_ida: add an API to return free tags

From: Shaohua Li
Date: Fri Oct 11 2013 - 21:02:55 EST


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
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