Commit 3192b920 authored by Christoph Lameter's avatar Christoph Lameter Committed by Pekka Enberg
Browse files

slab, slub, slob: Unify alignment definition 



Every slab has its on alignment definition in include/linux/sl?b_def.h. Extract those
and define a common set in include/linux/slab.h.

SLOB: As notes sometimes we need double word alignment on 32 bit. This gives all
structures allocated by SLOB a unsigned long long alignment like the others do.

SLAB: If ARCH_SLAB_MINALIGN is not set SLAB would set ARCH_SLAB_MINALIGN to
zero meaning no alignment at all. Give it the default unsigned long long alignment.

Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
parent bd50cfa8

include/linux/slab.h

+10 −0
Original line number Diff line number Diff line
@@ -133,6 +133,16 @@ unsigned int kmem_cache_size(struct kmem_cache *); 
#define KMALLOC_MAX_SIZE	(1UL << KMALLOC_SHIFT_HIGH)

#define KMALLOC_MAX_ORDER	(KMALLOC_SHIFT_HIGH - PAGE_SHIFT)



#ifdef ARCH_DMA_MINALIGN

#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN

#else

#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)

#endif



#ifndef ARCH_SLAB_MINALIGN

#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)

#endif



/*

 * Common kmalloc functions provided by all allocators

 */

include/linux/slab_def.h

+0 −26
Original line number Diff line number Diff line
@@ -17,32 +17,6 @@ 


#include <trace/events/kmem.h>



/*

 * Enforce a minimum alignment for the kmalloc caches.

 * Usually, the kmalloc caches are cache_line_size() aligned, except when

 * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.

 * Some archs want to perform DMA into kmalloc caches and need a guaranteed

 * alignment larger than the alignment of a 64-bit integer.

 * ARCH_KMALLOC_MINALIGN allows that.

 * Note that increasing this value may disable some debug features.

 */

#ifdef ARCH_DMA_MINALIGN

#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN

#else

#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)

#endif



#ifndef ARCH_SLAB_MINALIGN

/*

 * Enforce a minimum alignment for all caches.

 * Intended for archs that get misalignment faults even for BYTES_PER_WORD

 * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.

 * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables

 * some debug features.

 */

#define ARCH_SLAB_MINALIGN 0

#endif



/*

 * struct kmem_cache

 *

include/linux/slob_def.h

+0 −10
Original line number Diff line number Diff line 
#ifndef __LINUX_SLOB_DEF_H

#define __LINUX_SLOB_DEF_H



#ifdef ARCH_DMA_MINALIGN

#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN

#else

#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long)

#endif



#ifndef ARCH_SLAB_MINALIGN

#define ARCH_SLAB_MINALIGN __alignof__(unsigned long)

#endif



void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);



static __always_inline void *kmem_cache_alloc(struct kmem_cache *cachep,

include/linux/slub_def.h

+0 −10
Original line number Diff line number Diff line
@@ -113,16 +113,6 @@ struct kmem_cache { 


#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)



#ifdef ARCH_DMA_MINALIGN

#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN

#else

#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)

#endif



#ifndef ARCH_SLAB_MINALIGN

#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)

#endif



/*

 * Maximum kmalloc object size handled by SLUB. Larger object allocations

 * are passed through to the page allocator. The page allocator "fastpath"

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