diff options
| -rw-r--r-- | mm/slub.c | 71 |
1 files changed, 64 insertions, 7 deletions
diff --git a/mm/slub.c b/mm/slub.c index f93adb915c00..71988f9b9c55 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2313,20 +2313,59 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags) } #endif +/* + * Conversion table for small slabs sizes / 8 to the index in the + * kmalloc array. This is necessary for slabs < 192 since we have non power + * of two cache sizes there. The size of larger slabs can be determined using + * fls. + */ +static s8 size_index[24] = { + 3, /* 8 */ + 4, /* 16 */ + 5, /* 24 */ + 5, /* 32 */ + 6, /* 40 */ + 6, /* 48 */ + 6, /* 56 */ + 6, /* 64 */ + 1, /* 72 */ + 1, /* 80 */ + 1, /* 88 */ + 1, /* 96 */ + 7, /* 104 */ + 7, /* 112 */ + 7, /* 120 */ + 7, /* 128 */ + 2, /* 136 */ + 2, /* 144 */ + 2, /* 152 */ + 2, /* 160 */ + 2, /* 168 */ + 2, /* 176 */ + 2, /* 184 */ + 2 /* 192 */ +}; + static struct kmem_cache *get_slab(size_t size, gfp_t flags) { - int index = kmalloc_index(size); + int index; - if (!index) - return ZERO_SIZE_PTR; + if (size <= 192) { + if (!size) + return ZERO_SIZE_PTR; - /* Allocation too large? */ - if (index < 0) - return NULL; + index = size_index[(size - 1) / 8]; + } else { + if (size > KMALLOC_MAX_SIZE) + return NULL; + + index = fls(size - 1); + } #ifdef CONFIG_ZONE_DMA - if ((flags & SLUB_DMA)) + if (unlikely((flags & SLUB_DMA))) return dma_kmalloc_cache(index, flags); + #endif return &kmalloc_caches[index]; } @@ -2532,6 +2571,24 @@ void __init kmem_cache_init(void) caches++; } + + /* + * Patch up the size_index table if we have strange large alignment + * requirements for the kmalloc array. This is only the case for + * mips it seems. The standard arches will not generate any code here. + * + * Largest permitted alignment is 256 bytes due to the way we + * handle the index determination for the smaller caches. + * + * Make sure that nothing crazy happens if someone starts tinkering + * around with ARCH_KMALLOC_MINALIGN + */ + BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || + (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); + + for (i = 8; i < KMALLOC_MIN_SIZE;i++) + size_index[(i - 1) / 8] = KMALLOC_SHIFT_LOW; + slab_state = UP; /* Provide the correct kmalloc names now that the caches are up */ |
