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Commit 65c02d4c authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
Browse files

SLUB: add support for dynamic cacheline size determination 



SLUB currently assumes that the cacheline size is static.  However, i386 f.e.
supports dynamic cache line size determination.

Use cache_line_size() instead of L1_CACHE_BYTES in the allocator.

That also explains the purpose of SLAB_HWCACHE_ALIGN.  So we will need to keep
that one around to allow dynamic aligning of objects depending on boot
determination of the cache line size.

[akpm@linux-foundation.org: need to define it before we use it]
Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 97416ce8

mm/slub.c

+10 −5
Original line number Diff line number Diff line
@@ -157,6 +157,11 @@ 
/* Internal SLUB flags */

#define __OBJECT_POISON 0x80000000	/* Poison object */



/* Not all arches define cache_line_size */

#ifndef cache_line_size

#define cache_line_size()	L1_CACHE_BYTES

#endif



static int kmem_size = sizeof(struct kmem_cache);



#ifdef CONFIG_SMP
@@ -1480,8 +1485,8 @@ static unsigned long calculate_alignment(unsigned long flags, 
	 * then use it.

	 */

	if ((flags & SLAB_HWCACHE_ALIGN) &&

			size > L1_CACHE_BYTES / 2)

		return max_t(unsigned long, align, L1_CACHE_BYTES);

			size > cache_line_size() / 2)

		return max_t(unsigned long, align, cache_line_size());



	if (align < ARCH_SLAB_MINALIGN)

		return ARCH_SLAB_MINALIGN;
@@ -1667,8 +1672,8 @@ static int calculate_sizes(struct kmem_cache *s) 
		size += sizeof(void *);

	/*

	 * Determine the alignment based on various parameters that the

	 * user specified (this is unecessarily complex due to the attempt

	 * to be compatible with SLAB. Should be cleaned up some day).

	 * user specified and the dynamic determination of cache line size

	 * on bootup.

	 */

	align = calculate_alignment(flags, align, s->objsize);
@@ -2280,7 +2285,7 @@ void __init kmem_cache_init(void) 


	printk(KERN_INFO "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"

		" Processors=%d, Nodes=%d\n",

		KMALLOC_SHIFT_HIGH, L1_CACHE_BYTES,

		KMALLOC_SHIFT_HIGH, cache_line_size(),

		slub_min_order, slub_max_order, slub_min_objects,

		nr_cpu_ids, nr_node_ids);

}