Re: [PATCH] Use extents for recording what swap is allocated.

[Pavel Machek]

Hi!

> > Switch from bitmaps to using extents to record what swap is allocated;
> > they make more efficient use of memory, particularly where the allocated
> > storage is small and the swap space is large.
> 
> As I said before, I like the overall idea, but I have a bunch of
> comments.

Okay, if Rafael likes it... lets take a look.

First... what is the _worst case_ overhead? AFAICT extents are very
good at the best case, but tend to suck for the worst case...?

> > +#include <linux/suspend.h>
> > +#include "extent.h"
> > +
> > +/* suspend_get_extent
> > + *
> > + * Returns a free extent. May fail, returning NULL instead.
> > + */

Your comments are nice, and quite close to linuxdoc... Can we make
them proper linuxdoc?

> > +/* suspend_put_extent_chain.
> > + *
> > + * Frees a whole chain of extents.
> > + */
> > +void suspend_put_extent_chain(struct extent_chain *chain)
> 
> I'd call it suspend_free_all_extents().

This is actually important. As it does undocditional free(), it may
not be called "put".

> > +#ifndef EXTENT_H
> > +#define EXTENT_H
> > +
> > +struct extent {
> > +	unsigned long minimum, maximum;
> 
> Well, I'd use shorter names, but whatever.

Actually, minimum and 
	  maximum look too similar. start/end are really better names.

								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/