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-rw-r--r--mm/slub.c71
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 */