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

From: Pekka Enberg
Date: Tue Feb 17 2009 - 14:43:23 EST


On Tue, Feb 17, 2009 at 12:05:07PM -0500, Christoph Lameter wrote:
>> Index: linux-2.6/include/linux/slub_def.h
>> ===================================================================
>> --- linux-2.6.orig/include/linux/slub_def.h 2009-02-17 10:45:51.000000000 -0600
>> +++ linux-2.6/include/linux/slub_def.h 2009-02-17 11:06:53.000000000 -0600
>> @@ -121,10 +121,21 @@
>> #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
>>
>> /*
>> + * Maximum kmalloc object size handled by SLUB. Larger object allocations
>> + * are passed through to the page allocator. The page allocator "fastpath"
>> + * is relatively slow so we need this value sufficiently high so that
>> + * performance critical objects are allocated through the SLUB fastpath.
>> + *
>> + * This should be dropped to PAGE_SIZE / 2 once the page allocator
>> + * "fastpath" becomes competitive with the slab allocator fastpaths.
>> + */
>> +#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.
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