linux-kernel - Re: [PATCH] sbitmap: don't update the allocation hint on clear after resize

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Date:   Sat, 17 Sep 2016 12:49:27 -0700
From:   Omar Sandoval <osandov@...ndov.com>
To:     Jens Axboe <axboe@...com>
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-team@...com, Alexei Starovoitov <ast@...com>
Subject: Re: [PATCH] sbitmap: don't update the allocation hint on clear after
 resize

On Sat, Sep 17, 2016 at 01:39:59PM -0600, Jens Axboe wrote:
> On 09/17/2016 01:20 PM, Omar Sandoval wrote:
> > From: Omar Sandoval <osandov@...com>
> > 
> > If we have a bunch of high-numbered bits allocated and then we resize
> > the struct sbitmap_queue, when those bits get cleared, we'll update the
> > hint and then have to re-randomize it repeatedly. Avoid that by checking
> > that the cleared bit is still a valid hint. No measurable performance
> > difference in the common case.
> > 
> > Signed-off-by: Omar Sandoval <osandov@...com>
> > ---
> > Jens,
> > 
> > Small tweak to patch 6 that occurred to me after I sent the series out.
> > Feel free to fold it in to patch 6 or apply it separately as you see
> > fit.
> 
> No worries. I can't fold since the series was already applied, so I just
> added the extra patch.
> 

Okay with me, thanks!

-- 
Omar