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48a270554a
Attach the malloc attribute to a few allocation functions. This helps
gcc generate better code by telling it that the return value doesn't
alias any existing pointers (which is even more valuable given the
pessimizations implied by -fno-strict-aliasing).
A simple example of what this allows gcc to do can be seen by looking at
the last part of drm_atomic_helper_plane_reset:
plane->state = kzalloc(sizeof(*plane->state), GFP_KERNEL);
if (plane->state) {
plane->state->plane = plane;
plane->state->rotation = BIT(DRM_ROTATE_0);
}
which compiles to
e8 99 bf d6 ff callq ffffffff8116d540 <kmem_cache_alloc_trace>
48 85 c0 test %rax,%rax
48 89 83 40 02 00 00 mov %rax,0x240(%rbx)
74 11 je ffffffff814015c4 <drm_atomic_helper_plane_reset+0x64>
48 89 18 mov %rbx,(%rax)
48 8b 83 40 02 00 00 mov 0x240(%rbx),%rax [*]
c7 40 40 01 00 00 00 movl $0x1,0x40(%rax)
With this patch applied, the instruction at [*] is elided, since the
store to plane->state->plane is known to not alter the value of
plane->state.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
77 lines
2.4 KiB
C
77 lines
2.4 KiB
C
/*
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* memory buffer pool support
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*/
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#ifndef _LINUX_MEMPOOL_H
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#define _LINUX_MEMPOOL_H
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#include <linux/wait.h>
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#include <linux/compiler.h>
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struct kmem_cache;
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typedef void * (mempool_alloc_t)(gfp_t gfp_mask, void *pool_data);
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typedef void (mempool_free_t)(void *element, void *pool_data);
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typedef struct mempool_s {
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spinlock_t lock;
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int min_nr; /* nr of elements at *elements */
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int curr_nr; /* Current nr of elements at *elements */
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void **elements;
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void *pool_data;
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mempool_alloc_t *alloc;
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mempool_free_t *free;
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wait_queue_head_t wait;
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} mempool_t;
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extern mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
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mempool_free_t *free_fn, void *pool_data);
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extern mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
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mempool_free_t *free_fn, void *pool_data,
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gfp_t gfp_mask, int nid);
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extern int mempool_resize(mempool_t *pool, int new_min_nr);
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extern void mempool_destroy(mempool_t *pool);
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extern void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) __malloc;
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extern void mempool_free(void *element, mempool_t *pool);
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/*
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* A mempool_alloc_t and mempool_free_t that get the memory from
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* a slab cache that is passed in through pool_data.
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* Note: the slab cache may not have a ctor function.
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*/
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void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data);
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void mempool_free_slab(void *element, void *pool_data);
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static inline mempool_t *
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mempool_create_slab_pool(int min_nr, struct kmem_cache *kc)
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{
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return mempool_create(min_nr, mempool_alloc_slab, mempool_free_slab,
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(void *) kc);
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}
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/*
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* a mempool_alloc_t and a mempool_free_t to kmalloc and kfree the
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* amount of memory specified by pool_data
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*/
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void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data);
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void mempool_kfree(void *element, void *pool_data);
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static inline mempool_t *mempool_create_kmalloc_pool(int min_nr, size_t size)
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{
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return mempool_create(min_nr, mempool_kmalloc, mempool_kfree,
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(void *) size);
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}
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/*
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* A mempool_alloc_t and mempool_free_t for a simple page allocator that
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* allocates pages of the order specified by pool_data
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*/
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void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data);
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void mempool_free_pages(void *element, void *pool_data);
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static inline mempool_t *mempool_create_page_pool(int min_nr, int order)
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{
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return mempool_create(min_nr, mempool_alloc_pages, mempool_free_pages,
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(void *)(long)order);
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}
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#endif /* _LINUX_MEMPOOL_H */
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