[PATCH] cpuset memory spread slab cache hooks

Change the kmem_cache_create calls for certain slab caches to support cpuset
memory spreading.

See the previous patches, cpuset_mem_spread, for an explanation of cpuset
memory spreading, and cpuset_mem_spread_slab_cache for the slab cache support
for memory spreading.

The slab caches marked for now are: dentry_cache, inode_cache, some xfs slab
caches, and buffer_head. This list may change over time. In particular,
other file system types that are used extensively on large NUMA systems may
want to allow for spreading their directory and inode slab cache entries.

Signed-off-by: Paul Jackson <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/buffer.c

···
 	int nrpages;
 
 	bh_cachep = kmem_cache_create("buffer_head",
-			sizeof(struct buffer_head), 0,
-			SLAB_RECLAIM_ACCOUNT|SLAB_PANIC, init_buffer_head, NULL);
+					sizeof(struct buffer_head), 0,
+					(SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
+					SLAB_MEM_SPREAD),
+					init_buffer_head,
+					NULL);
 
 	/*
 	 * Limit the bh occupancy to 10% of ZONE_NORMAL

fs/dcache.c

···
 	dentry_cache = kmem_cache_create("dentry_cache",
 					 sizeof(struct dentry),
 					 0,
-					 SLAB_RECLAIM_ACCOUNT|SLAB_PANIC,
+					 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
+					 SLAB_MEM_SPREAD),
 					 NULL, NULL);
 	
 	set_shrinker(DEFAULT_SEEKS, shrink_dcache_memory);

fs/inode.c

···
 	int loop;
 
 	/* inode slab cache */
-	inode_cachep = kmem_cache_create("inode_cache", sizeof(struct inode),
-				0, SLAB_RECLAIM_ACCOUNT|SLAB_PANIC, init_once, NULL);
+	inode_cachep = kmem_cache_create("inode_cache",
+					 sizeof(struct inode),
+					 0,
+					 (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
+					 SLAB_MEM_SPREAD),
+					 init_once,
+					 NULL);
 	set_shrinker(DEFAULT_SEEKS, shrink_icache_memory);
 
 	/* Hash may have been set up in inode_init_early */

fs/xfs/linux-2.6/kmem.h

···
 
 #define KM_ZONE_HWALIGN	SLAB_HWCACHE_ALIGN
 #define KM_ZONE_RECLAIM	SLAB_RECLAIM_ACCOUNT
-#define KM_ZONE_SPREAD	0
+#define KM_ZONE_SPREAD	SLAB_MEM_SPREAD
 
 #define kmem_zone	kmem_cache
 #define kmem_zone_t	struct kmem_cache