Commit 9c01e9af authored by Vlastimil Babka's avatar Vlastimil Babka
Browse files

mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled 



The fields 'next' and 'slabs' are only used when CONFIG_SLUB_CPU_PARTIAL
is enabled. We can put their definition to #ifdef to prevent accidental
use when disabled.

Currenlty show_slab_objects() and slabs_cpu_partial_show() contain code
accessing the slabs field that's effectively dead with
CONFIG_SLUB_CPU_PARTIAL=n through the wrappers slub_percpu_partial() and
slub_percpu_partial_read_once(), but to prevent a compile error, we need
to hide all this code behind #ifdef.

Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
Reviewed-by: default avatarHyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: default avatarRoman Gushchin <guro@fb.com>
Tested-by: default avatarHyeonggon Yoo <42.hyeyoo@gmail.com>
parent 662188c3

mm/slab.h

+2 −0
Original line number Diff line number Diff line
@@ -25,10 +25,12 @@ struct slab { 
	union {

		struct list_head slab_list;

		struct rcu_head rcu_head;

#ifdef CONFIG_SLUB_CPU_PARTIAL

		struct {

			struct slab *next;

			int slabs;	/* Nr of slabs left */

		};

#endif

	};

	struct kmem_cache *slab_cache;

	/* Double-word boundary */

mm/slub.c

+6 −2
Original line number Diff line number Diff line
@@ -5258,6 +5258,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s, 
			total += x;

			nodes[node] += x;



#ifdef CONFIG_SLUB_CPU_PARTIAL

			slab = slub_percpu_partial_read_once(c);

			if (slab) {

				node = slab_nid(slab);
@@ -5270,6 +5271,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s, 
				total += x;

				nodes[node] += x;

			}

#endif

		}

	}
@@ -5469,9 +5471,10 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf) 
{

	int objects = 0;

	int slabs = 0;

	int cpu;

	int cpu __maybe_unused;

	int len = 0;



#ifdef CONFIG_SLUB_CPU_PARTIAL

	for_each_online_cpu(cpu) {

		struct slab *slab;
@@ -5480,12 +5483,13 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf) 
		if (slab)

			slabs += slab->slabs;

	}

#endif



	/* Approximate half-full slabs, see slub_set_cpu_partial() */

	objects = (slabs * oo_objects(s->oo)) / 2;

	len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);



#ifdef CONFIG_SMP

#if defined(CONFIG_SLUB_CPU_PARTIAL) && defined(CONFIG_SMP)

	for_each_online_cpu(cpu) {

		struct slab *slab;