diff options
Diffstat (limited to 'mm/slab_common.c')
| -rw-r--r-- | mm/slab_common.c | 111 |
1 files changed, 104 insertions, 7 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c index 1560a1546bb1..70943a4c1c4b 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -392,6 +392,98 @@ kmem_cache_create(const char *name, unsigned int size, unsigned int align, } EXPORT_SYMBOL(kmem_cache_create); +static struct kmem_cache *kmem_buckets_cache __ro_after_init; + +/** + * kmem_buckets_create - Create a set of caches that handle dynamic sized + * allocations via kmem_buckets_alloc() + * @name: A prefix string which is used in /proc/slabinfo to identify this + * cache. The individual caches with have their sizes as the suffix. + * @flags: SLAB flags (see kmem_cache_create() for details). + * @useroffset: Starting offset within an allocation that may be copied + * to/from userspace. + * @usersize: How many bytes, starting at @useroffset, may be copied + * to/from userspace. + * @ctor: A constructor for the objects, run when new allocations are made. + * + * Cannot be called within an interrupt, but can be interrupted. + * + * Return: a pointer to the cache on success, NULL on failure. When + * CONFIG_SLAB_BUCKETS is not enabled, ZERO_SIZE_PTR is returned, and + * subsequent calls to kmem_buckets_alloc() will fall back to kmalloc(). + * (i.e. callers only need to check for NULL on failure.) + */ +kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, + unsigned int useroffset, + unsigned int usersize, + void (*ctor)(void *)) +{ + kmem_buckets *b; + int idx; + + /* + * When the separate buckets API is not built in, just return + * a non-NULL value for the kmem_buckets pointer, which will be + * unused when performing allocations. + */ + if (!IS_ENABLED(CONFIG_SLAB_BUCKETS)) + return ZERO_SIZE_PTR; + + if (WARN_ON(!kmem_buckets_cache)) + return NULL; + + b = kmem_cache_alloc(kmem_buckets_cache, GFP_KERNEL|__GFP_ZERO); + if (WARN_ON(!b)) + return NULL; + + flags |= SLAB_NO_MERGE; + + for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) { + char *short_size, *cache_name; + unsigned int cache_useroffset, cache_usersize; + unsigned int size; + + if (!kmalloc_caches[KMALLOC_NORMAL][idx]) + continue; + + size = kmalloc_caches[KMALLOC_NORMAL][idx]->object_size; + if (!size) + continue; + + short_size = strchr(kmalloc_caches[KMALLOC_NORMAL][idx]->name, '-'); + if (WARN_ON(!short_size)) + goto fail; + + cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1); + if (WARN_ON(!cache_name)) + goto fail; + + if (useroffset >= size) { + cache_useroffset = 0; + cache_usersize = 0; + } else { + cache_useroffset = useroffset; + cache_usersize = min(size - cache_useroffset, usersize); + } + (*b)[idx] = kmem_cache_create_usercopy(cache_name, size, + 0, flags, cache_useroffset, + cache_usersize, ctor); + kfree(cache_name); + if (WARN_ON(!(*b)[idx])) + goto fail; + } + + return b; + +fail: + for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) + kmem_cache_destroy((*b)[idx]); + kfree(b); + + return NULL; +} +EXPORT_SYMBOL(kmem_buckets_create); + #ifdef SLAB_SUPPORTS_SYSFS /* * For a given kmem_cache, kmem_cache_destroy() should only be called @@ -617,11 +709,12 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name, s->size = s->object_size = size; /* - * For power of two sizes, guarantee natural alignment for kmalloc - * caches, regardless of SL*B debugging options. + * kmalloc caches guarantee alignment of at least the largest + * power-of-two divisor of the size. For power-of-two sizes, + * it is the size itself. */ - if (is_power_of_2(size)) - align = max(align, size); + if (flags & SLAB_KMALLOC) + align = max(align, 1U << (ffs(size) - 1)); s->align = calculate_alignment(flags, align, size); #ifdef CONFIG_HARDENED_USERCOPY @@ -653,8 +746,7 @@ static struct kmem_cache *__init create_kmalloc_cache(const char *name, return s; } -struct kmem_cache * -kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init = +kmem_buckets kmalloc_caches[NR_KMALLOC_TYPES] __ro_after_init = { /* initialization for https://llvm.org/pr42570 */ }; EXPORT_SYMBOL(kmalloc_caches); @@ -703,7 +795,7 @@ size_t kmalloc_size_roundup(size_t size) * The flags don't matter since size_index is common to all. * Neither does the caller for just getting ->object_size. */ - return kmalloc_slab(size, GFP_KERNEL, 0)->object_size; + return kmalloc_slab(size, NULL, GFP_KERNEL, 0)->object_size; } /* Above the smaller buckets, size is a multiple of page size. */ @@ -932,6 +1024,11 @@ void __init create_kmalloc_caches(void) /* Kmalloc array is now usable */ slab_state = UP; + + if (IS_ENABLED(CONFIG_SLAB_BUCKETS)) + kmem_buckets_cache = kmem_cache_create("kmalloc_buckets", + sizeof(kmem_buckets), + 0, SLAB_NO_MERGE, NULL); } /** |