Re: [PATCH] cfq: reorder cfq_queue removing padding on 64bit &allowing more objects/slab in it's kmem_cache

From: Richard Kennedy
Date: Mon Feb 15 2010 - 10:32:25 EST


On Mon, 2010-02-15 at 09:16 -0500, Vivek Goyal wrote:
> On Mon, Feb 15, 2010 at 02:10:36PM +0000, Richard Kennedy wrote:
> > This removes 8 bytes of padding from struct cfq_queue on 64 bit builds,
> > shrinking it's size to 256 bytes, so fitting into 1 fewer cachelines and
> > allowing 1 more object/slab in it's kmem_cache.
> >
> >
> > Signed-off-by: Richard Kennedy <richard@xxxxxxxxxxxxxxx>
> > ----
> > patch against 2.6.33-rc8
> > tested on x86_64 AMDX2
> >
> > regards
> > Richard
> >
> >
> > diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
> > index 023f4e6..db4c127 100644
> > --- a/block/cfq-iosched.c
> > +++ b/block/cfq-iosched.c
> > @@ -116,10 +116,10 @@ struct cfq_queue {
> > unsigned long dispatch_start;
> > unsigned int allocated_slice;
> > /* time when first request from queue completed and slice started. */
> > + unsigned int slice_dispatch;
>
> Can you move it above the comment. The comment describes "slice_start" and
> now comment and variable have been separated.
>
> Vivek
Sure, no problem. I'll send out a new version.
Richard

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