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SubjectRE: [patch] add an iterator index in struct pagevec
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Andrew Morton wrote on Monday, December 04, 2006 9:45 PM
> On Mon, 4 Dec 2006 21:21:31 -0800
> "Chen, Kenneth W" <kenneth.w.chen@intel.com> wrote:
>
> > pagevec is never expected to be more than PAGEVEC_SIZE, I think a
> > unsigned char is enough to count them. This patch makes nr, cold
> > to be unsigned char
>
> Is that on the right side of the speed/space tradeoff?

I haven't measured speed. Size wise, making them char shrinks vmlinux
text size by 112 bytes on x86_64 (using default config option).


> I must say I'm a bit skeptical about the need for this. But I haven't
> looked closely at the blockdev-specific dio code yet.

It was suggested to declare another struct that embeds pagevec to perform
iteration. But I prefer to have pagevec having the capability, it is
more compact this way.

It would be nice if you can review blockdev-specific dio code. I would
appreciate it very much.

- Ken
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