Re: [PATCH RFC 0/2] percpu_ida: Take into account CPU topology when stealing tags

[Christoph Hellwig]

On Fri, May 02, 2014 at 10:41:40AM -0600, Jens Axboe wrote:
> > At least for SCSI devices _tag space_ is plenty, it's just the we
> > artifically limit our tag space to the queue depth to avoid having to
> > track that one separately.  In addition we also preallocaste a request
> > for each tag, so even if we would track the queue depth separately
> > we would waste a lot of memory.
> 
> In practice it comes out to the same, it's not feasible to run a much
> larger space and track on queue depth. So I don't think that changes the
> conclusion for SCSI.

Agreed.  Just had to check if my smart ass hat still fits this morning..

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