Re: [PATCH 09/10] Change table chaining layout

[Jeff Garzik]

Matt Mackall wrote:
> On Mon, Oct 22, 2007 at 11:52:51PM +0100, Alan Cox wrote:
> > On Mon, 22 Oct 2007 16:47:07 -0500
> > Matt Mackall <mpm@xxxxxxxxxxx> wrote:
> >
> > > On Mon, Oct 22, 2007 at 05:21:30PM -0400, Jeff Garzik wrote:
> > > > Alan Cox wrote:
> > > > > Why can't we just make the list one item longer than the entry count and
> > > > > stick a NULL on the end of it like normal people ?
> > > > Certainly seems safer than the current "let's run off the end of the 
> > > > list if anything bad happens" setup...  And I do not think allocating 
> > > > n+1 scatterlist entries will have much of a negative impact.
> > > It'll mean m-1 scatterlists fit on a slab.
> > Is that really a credible space issue ?
>
> Yes. Especially if m is 2 or 1. A scatterlist on 64-bit x86 looks like
> it takes 32 bytes, which means 128 elements fit on a page. One more
> spills - ouch!

 ...and its trivial to reduce that number to 127 without noticeable 
effect, really.

	Jeff



-
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/