mm: slabinfo: remove CONFIG_SLABINFO

According to discussion with Christoph
(https://marc.info/?l=linux-kernel&m=150695909709711&w=2), it sounds like
it is pointless to keep CONFIG_SLABINFO around.

This patch removes the CONFIG_SLABINFO config option, but /proc/slabinfo
is still available.

[yang.s@alibaba-inc.com: v11]
  Link: http://lkml.kernel.org/r/1507656303-103845-3-git-send-email-yang.s@alibaba-inc.com
Link: http://lkml.kernel.org/r/1507152550-46205-3-git-send-email-yang.s@alibaba-inc.com
Signed-off-by: Yang Shi <yang.s@alibaba-inc.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

init/Kconfig

@@ -1664,12 +1664,6 @@ config HAVE_GENERIC_DMA_COHERENT
 	bool
 	default n
 
-config SLABINFO
-	bool
-	depends on PROC_FS
-	depends on SLAB || SLUB_DEBUG
-	default y
-
 config RT_MUTEXES
 	bool
 

mm/memcontrol.c

@@ -4049,7 +4049,7 @@ static struct cftype mem_cgroup_legacy_files[] = {
 		.write = mem_cgroup_reset,
 		.read_u64 = mem_cgroup_read_u64,
 	},
-#ifdef CONFIG_SLABINFO
+#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
 	{
 		.name = "kmem.slabinfo",
 		.seq_start = memcg_slab_start,

mm/slab.c

@@ -4097,7 +4097,6 @@ out:
 	schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC));
 }
 
-#ifdef CONFIG_SLABINFO
 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
 {
 	unsigned long active_objs, num_objs, active_slabs;
@@ -4405,7 +4404,6 @@ static int __init slab_proc_init(void)
 	return 0;
 }
 module_init(slab_proc_init);
-#endif
 
 #ifdef CONFIG_HARDENED_USERCOPY
 /*

mm/slab_common.c

@@ -1184,8 +1184,7 @@ void cache_random_seq_destroy(struct kmem_cache *cachep)
 }
 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
 
-#ifdef CONFIG_SLABINFO
-
+#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
 #ifdef CONFIG_SLAB
 #define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR)
 #else
@@ -1281,7 +1280,7 @@ static int slab_show(struct seq_file *m, void *p)
 	return 0;
 }
 
-#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
+#if defined(CONFIG_MEMCG)
 void *memcg_slab_start(struct seq_file *m, loff_t *pos)
 {
 	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
@@ -1355,7 +1354,7 @@ static int __init slab_proc_init(void)
 	return 0;
 }
 module_init(slab_proc_init);
-#endif /* CONFIG_SLABINFO */
+#endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
 
 static __always_inline void *__do_krealloc(const void *p, size_t new_size,
 					   gfp_t flags)

mm/slub.c

@@ -5852,7 +5852,7 @@ __initcall(slab_sysfs_init);
 /*
  * The /proc/slabinfo ABI
  */
-#ifdef CONFIG_SLABINFO
+#ifdef CONFIG_SLUB_DEBUG
 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
 {
 	unsigned long nr_slabs = 0;
@@ -5884,4 +5884,4 @@ ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 {
 	return -EIO;
 }
-#endif /* CONFIG_SLABINFO */
+#endif /* CONFIG_SLUB_DEBUG */