On Mon, Oct 22, 2007 at 11:52:51PM +0100, Alan Cox wrote: > On Mon, 22 Oct 2007 16:47:07 -0500 > Matt Mackall <[EMAIL PROTECTED]> 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! But maybe chaining means this doesn't matter any more. Maybe we can even pick a nice moderate sg size and reduce the number of mempools we need for these things. -- Mathematics is the supreme nostalgia of our time. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
