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mm/slab: move kfree() from slab_common.c to slub.c 

This should result in better code. Currently kfree() makes a function
call between compilation units to __kmem_cache_free() which does its own
virt_to_slab(), throwing away the struct slab pointer we already had in
kfree(). Now it can be reused. Additionally kfree() can now inline the
whole SLUB freeing fastpath.

Also move over free_large_kmalloc() as the only callsites are now in
slub.c, and make it static.

Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
This commit is contained in:
Vlastimil Babka 2023-10-03 15:27:11 +02:00
parent b52ef56e9b
commit b774d3e326
3 changed files with 46 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
mm/slab.h
View File

@ -395,8 +395,6 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags, unsigned long caller);
void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags,
int node, size_t orig_size,
unsigned long caller);
void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller);
gfp_t kmalloc_fix_flags(gfp_t flags);
/* Functions provided by the slab allocators */
@ -559,8 +557,6 @@ static inline int memcg_alloc_slab_cgroups(struct slab *slab,
}
#endif /* CONFIG_MEMCG_KMEM */
void free_large_kmalloc(struct folio *folio, void *object);
size_t __ksize(const void *objp);
static inline size_t slab_ksize(const struct kmem_cache *s)

45
mm/slab_common.c
View File

@ -963,22 +963,6 @@ void __init create_kmalloc_caches(slab_flags_t flags)
slab_state = UP;
}
void free_large_kmalloc(struct folio *folio, void *object)
{
unsigned int order = folio_order(folio);
if (WARN_ON_ONCE(order == 0))
pr_warn_once("object pointer: 0x%p\n", object);
kmemleak_free(object);
kasan_kfree_large(object);
kmsan_kfree_large(object);
mod_lruvec_page_state(folio_page(folio, 0), NR_SLAB_UNRECLAIMABLE_B,
-(PAGE_SIZE << order));
__free_pages(folio_page(folio, 0), order);
}
static void *__kmalloc_large_node(size_t size, gfp_t flags, int node);
static __always_inline
void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
@ -1023,35 +1007,6 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
}
EXPORT_SYMBOL(__kmalloc_node_track_caller);
/**
* kfree - free previously allocated memory
* @object: pointer returned by kmalloc() or kmem_cache_alloc()
*
* If @object is NULL, no operation is performed.
*/
void kfree(const void *object)
{
struct folio *folio;
struct slab *slab;
struct kmem_cache *s;
trace_kfree(_RET_IP_, object);
if (unlikely(ZERO_OR_NULL_PTR(object)))
return;
folio = virt_to_folio(object);
if (unlikely(!folio_test_slab(folio))) {
free_large_kmalloc(folio, (void *)object);
return;
}
slab = folio_slab(folio);
s = slab->slab_cache;
__kmem_cache_free(s, (void *)object, _RET_IP_);
}
EXPORT_SYMBOL(kfree);
/**
* __ksize -- Report full size of underlying allocation
* @object: pointer to the object

51
mm/slub.c
View File

@ -4197,11 +4197,6 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
return cachep;
}
void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller)
{
slab_free(s, virt_to_slab(x), x, NULL, &x, 1, caller);
}
/**
* kmem_cache_free - Deallocate an object
* @s: The cache the allocation was from.
@ -4220,6 +4215,52 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
}
EXPORT_SYMBOL(kmem_cache_free);
static void free_large_kmalloc(struct folio *folio, void *object)
{
unsigned int order = folio_order(folio);
if (WARN_ON_ONCE(order == 0))
pr_warn_once("object pointer: 0x%p\n", object);
kmemleak_free(object);
kasan_kfree_large(object);
kmsan_kfree_large(object);
mod_lruvec_page_state(folio_page(folio, 0), NR_SLAB_UNRECLAIMABLE_B,
-(PAGE_SIZE << order));
__free_pages(folio_page(folio, 0), order);
}
/**
* kfree - free previously allocated memory
* @object: pointer returned by kmalloc() or kmem_cache_alloc()
*
* If @object is NULL, no operation is performed.
*/
void kfree(const void *object)
{
struct folio *folio;
struct slab *slab;
struct kmem_cache *s;
void *x = (void *)object;
trace_kfree(_RET_IP_, object);
if (unlikely(ZERO_OR_NULL_PTR(object)))
return;
folio = virt_to_folio(object);
if (unlikely(!folio_test_slab(folio))) {
free_large_kmalloc(folio, (void *)object);
return;
}
slab = folio_slab(folio);
s = slab->slab_cache;
slab_free(s, slab, x, NULL, &x, 1, _RET_IP_);
}
EXPORT_SYMBOL(kfree);
struct detached_freelist {
struct slab *slab;
void *tail;