mm/slab_common: support the slub_debug boot option on specific object size

The slub_debug=PU,kmalloc-xx cannot work because in the
create_kmalloc_caches() the s->name is created after the
create_kmalloc_cache() is called.  The name is NULL in the
create_kmalloc_cache() so the kmem_cache_flags() would not set the
slub_debug flags to the s->flags.  The fix here set up a kmalloc_names
string array for the initialization purpose and delete the dynamic name
creation of kmalloc_caches.

[akpm@linux-foundation.org: s/kmalloc_names/kmalloc_info/, tweak comment text]
Signed-off-by: Gavin Guo <gavin.guo@canonical.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 61 insertions, 23 deletions

diff --git a/include/linux/slab.h b/include/linux/slab.h
index ffd24c830151..96f0ea506b5c 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -153,8 +153,30 @@ size_t ksize(const void *);
 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
+/*
+ * The KMALLOC_LOOP_LOW is the definition for the for loop index start number
+ * to create the kmalloc_caches object in create_kmalloc_caches(). The first
+ * and the second are 96 and 192. You can see that in the kmalloc_index(), if
+ * the KMALLOC_MIN_SIZE <= 32, then return 1 (96). If KMALLOC_MIN_SIZE <= 64,
+ * then return 2 (192). If the KMALLOC_MIN_SIZE is bigger than 64, we don't
+ * need to initialize 96 and 192. Go directly to start the KMALLOC_SHIFT_LOW.
+ */
+#if KMALLOC_MIN_SIZE <= 32
+#define KMALLOC_LOOP_LOW 1
+#elif KMALLOC_MIN_SIZE <= 64
+#define KMALLOC_LOOP_LOW 2
+#else
+#define KMALLOC_LOOP_LOW KMALLOC_SHIFT_LOW
+#endif
+
 #else
 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
+/*
+ * The KMALLOC_MIN_SIZE of slub/slab/slob is 2^3/2^5/2^3. So, even slab is used.
+ * The KMALLOC_MIN_SIZE <= 32. The kmalloc-96 and kmalloc-192 should also be
+ * initialized.
+ */
+#define KMALLOC_LOOP_LOW 1
 #endif
 
 /*
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 999bb3424d44..84e14582a14c 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -784,6 +784,31 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
 }
 
 /*
+ * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
+ * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
+ * kmalloc-67108864.
+ */
+static struct {
+        const char *name;
+        unsigned long size;
+} const kmalloc_info[] __initconst = {
+        {NULL,                      0},         {"kmalloc-96",             96},
+        {"kmalloc-192",           192},         {"kmalloc-8",               8},
+        {"kmalloc-16",             16},         {"kmalloc-32",             32},
+        {"kmalloc-64",             64},         {"kmalloc-128",           128},
+        {"kmalloc-256",           256},         {"kmalloc-512",           512},
+        {"kmalloc-1024",         1024},         {"kmalloc-2048",         2048},
+        {"kmalloc-4096",         4096},         {"kmalloc-8192",         8192},
+        {"kmalloc-16384",       16384},         {"kmalloc-32768",       32768},
+        {"kmalloc-65536",       65536},         {"kmalloc-131072",     131072},
+        {"kmalloc-262144",     262144},         {"kmalloc-524288",     524288},
+        {"kmalloc-1048576",   1048576},         {"kmalloc-2097152",   2097152},
+        {"kmalloc-4194304",   4194304},         {"kmalloc-8388608",   8388608},
+        {"kmalloc-16777216", 16777216},         {"kmalloc-33554432", 33554432},
+        {"kmalloc-67108864", 67108864}
+};
+
+/*
  * Create the kmalloc array. Some of the regular kmalloc arrays
  * may already have been created because they were needed to
  * enable allocations for slab creation.
@@ -833,39 +858,30 @@ void __init create_kmalloc_caches(unsigned long flags)
                 for (i = 128 + 8; i <= 192; i += 8)
                         size_index[size_index_elem(i)] = 8;
         }
-        for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
+        for (i = KMALLOC_LOOP_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
                 if (!kmalloc_caches[i]) {
-                        kmalloc_caches[i] = create_kmalloc_cache(NULL,
-                                                        1 << i, flags);
+                        kmalloc_caches[i] = create_kmalloc_cache(
+                                                kmalloc_info[i].name,
+                                                kmalloc_info[i].size,
+                                                flags);
                 }
 
                 /*
-                 * Caches that are not of the two-to-the-power-of size.
-                 * These have to be created immediately after the
-                 * earlier power of two caches
+                 * "i == 2" is the "kmalloc-192" case which is the last special
+                 * case for initialization and it's the point to jump to
+                 * allocate the minimize size of the object. In slab allocator,
+                 * the KMALLOC_SHIFT_LOW = 5. So, it needs to skip 2^3 and 2^4
+                 * and go straight to allocate 2^5. If the ARCH_DMA_MINALIGN is
+                 * defined, it may be larger than 2^5 and here is also the
+                 * trick to skip the empty gap.
                  */
-                if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)
-                        kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags);
-
-                if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)
-                        kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags);
+                if (i == 2)
+                        i = (KMALLOC_SHIFT_LOW - 1);
         }
 
         /* Kmalloc array is now usable */
         slab_state = UP;
 
-        for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
-                struct kmem_cache *s = kmalloc_caches[i];
-                char *n;
-
-                if (s) {
-                        n = kasprintf(GFP_NOWAIT, "kmalloc-%d", kmalloc_size(i));
-
-                        BUG_ON(!n);
-                        s->name = n;
-                }
-        }
-
 #ifdef CONFIG_ZONE_DMA
         for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
                 struct kmem_cache *s = kmalloc_caches[i];