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

[ need to define it before we use it]
Signed-off-by: default avatarChristoph Lameter <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 97416ce8
......@@ -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
static int kmem_size = sizeof(struct kmem_cache);
......@@ -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());
......@@ -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, cache_line_size(),
slub_min_order, slub_max_order, slub_min_objects,
nr_cpu_ids, nr_node_ids);
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