mm/slub: remove the check for NULL kmalloc_caches

If the same size kmalloc cache already exists, it should not be created
again. So there is the check for NULL kmalloc_caches before calling the
kmalloc creation function. However, new_kmalloc_cache() itself checks NULL
kmalloc_cahces before cache creation. Therefore, the NULL check is not
necessary in this function.

Signed-off-by: Hyunmin Lee <hyunminlr@gmail.com>
Co-developed-by: Jeungwoo Yoo <casionwoo@gmail.com>
Signed-off-by: Jeungwoo Yoo <casionwoo@gmail.com>
Co-developed-by: Sangyun Kim <sangyun.kim@snu.ac.kr>
Signed-off-by: Sangyun Kim <sangyun.kim@snu.ac.kr>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

mm/slab_common.c

@@ -917,16 +917,14 @@ void __init create_kmalloc_caches(void)
 	 */
 	for (type = KMALLOC_NORMAL; type < NR_KMALLOC_TYPES; type++) {
 		/* Caches that are NOT of the two-to-the-power-of size. */
-		if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[type][1])
+		if (KMALLOC_MIN_SIZE <= 32)
 			new_kmalloc_cache(1, type);
-		if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[type][2])
+		if (KMALLOC_MIN_SIZE <= 64)
 			new_kmalloc_cache(2, type);
 
 		/* Caches that are of the two-to-the-power-of size. */
-		for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
-			if (!kmalloc_caches[type][i])
-				new_kmalloc_cache(i, type);
-		}
+		for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
+			new_kmalloc_cache(i, type);
 	}
 #ifdef CONFIG_RANDOM_KMALLOC_CACHES
 	random_kmalloc_seed = get_random_u64();