Re: [patch] SLQB slab allocator (try 2)

From: KOSAKI Motohiro
Date: Tue Feb 17 2009 - 19:48:26 EST


> On Tue, 17 Feb 2009, Pekka Enberg wrote:
>
> > >> +#define SLUB_MAX_SIZE (2 * PAGE_SIZE)
> >
> > On Tue, Feb 17, 2009 at 8:11 PM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
> > > This relies on PAGE_SIZE being 4k. If you want 8k, why don't you say
> > > so? Pekka did this explicitely.
> >
> > That could be a problem, sure. Especially for architecture that have 64 K pages.
>
> You could likely put a complicated formula in there instead. But 2 *
> PAGE_SIZE is simple and will work on all platforms regardless of pagesize.

I think 2 * PAGE_SIZE is best and the patch description is needed change.
it's because almost architecture use two pages for stack and current page
allocator don't have delayed consolidation mechanism for order-1 page.

In addition, if pekka patch (SLAB_LIMIT = 8K) run on ia64, 16K allocation
always fallback to page allocator and using 64K (4 times memory consumption!).

Am I misunderstand anything?



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