Commit b047501c authored by Vladimir Davydov's avatar Vladimir Davydov Committed by Linus Torvalds
Browse files

memcg: use generic slab iterators for showing slabinfo 



Let's use generic slab_start/next/stop for showing memcg caches info.  In
contrast to the current implementation, this will work even if all memcg
caches' info doesn't fit into a seq buffer (a page), plus it simply looks
neater.

Actually, the main reason I do this isn't mere cleanup.  I'm going to zap
the memcg_slab_caches list, because I find it useless provided we have the
slab_caches list, and this patch is a step in this direction.

It should be noted that before this patch an attempt to read
memory.kmem.slabinfo of a cgroup that doesn't have kmem limit set resulted
in -EIO, while after this patch it will silently show nothing except the
header, but I don't think it will frustrate anyone.

Signed-off-by: default avatarVladimir Davydov <vdavydov@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4ef461e8

include/linux/slab.h

+0 −4
Original line number Diff line number Diff line
@@ -513,10 +513,6 @@ struct memcg_cache_params { 


int memcg_update_all_caches(int num_memcgs);



struct seq_file;

int cache_show(struct kmem_cache *s, struct seq_file *m);

void print_slabinfo_header(struct seq_file *m);



/**

 * kmalloc_array - allocate memory for an array.

 * @n: number of elements.

mm/memcontrol.c

+4 −21
Original line number Diff line number Diff line
@@ -2547,26 +2547,6 @@ static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p) 
	return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg));

}



#ifdef CONFIG_SLABINFO

static int mem_cgroup_slabinfo_read(struct seq_file *m, void *v)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));

	struct memcg_cache_params *params;



	if (!memcg_kmem_is_active(memcg))

		return -EIO;



	print_slabinfo_header(m);



	mutex_lock(&memcg_slab_mutex);

	list_for_each_entry(params, &memcg->memcg_slab_caches, list)

		cache_show(memcg_params_to_cache(params), m);

	mutex_unlock(&memcg_slab_mutex);



	return 0;

}

#endif



static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp,

			     unsigned long nr_pages)

{
@@ -4708,7 +4688,10 @@ static struct cftype mem_cgroup_files[] = { 
#ifdef CONFIG_SLABINFO

	{

		.name = "kmem.slabinfo",

		.seq_show = mem_cgroup_slabinfo_read,

		.seq_start = slab_start,

		.seq_next = slab_next,

		.seq_stop = slab_stop,

		.seq_show = memcg_slab_show,

	},

#endif

#endif

mm/slab.h

+1 −0
Original line number Diff line number Diff line
@@ -360,5 +360,6 @@ static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) 
void *slab_start(struct seq_file *m, loff_t *pos);

void *slab_next(struct seq_file *m, void *p, loff_t *pos);

void slab_stop(struct seq_file *m, void *p);

int memcg_slab_show(struct seq_file *m, void *p);



#endif /* MM_SLAB_H */

mm/slab_common.c

+19 −6
Original line number Diff line number Diff line
@@ -811,7 +811,7 @@ EXPORT_SYMBOL(kmalloc_order_trace); 
#define SLABINFO_RIGHTS S_IRUSR

#endif



void print_slabinfo_header(struct seq_file *m)

static void print_slabinfo_header(struct seq_file *m)

{

	/*

	 * Output format version, so at least we can change it
@@ -876,7 +876,7 @@ memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info) 
	}

}



int cache_show(struct kmem_cache *s, struct seq_file *m)

static void cache_show(struct kmem_cache *s, struct seq_file *m)

{

	struct slabinfo sinfo;
@@ -895,7 +895,6 @@ int cache_show(struct kmem_cache *s, struct seq_file *m) 
		   sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);

	slabinfo_show_stats(m, s);

	seq_putc(m, '\n');

	return 0;

}



static int slab_show(struct seq_file *m, void *p)
@@ -904,10 +903,24 @@ static int slab_show(struct seq_file *m, void *p) 


	if (p == slab_caches.next)

		print_slabinfo_header(m);

	if (!is_root_cache(s))

	if (is_root_cache(s))

		cache_show(s, m);

	return 0;

}



#ifdef CONFIG_MEMCG_KMEM

int memcg_slab_show(struct seq_file *m, void *p)

{

	struct kmem_cache *s = list_entry(p, struct kmem_cache, list);

	struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));



	if (p == slab_caches.next)

		print_slabinfo_header(m);

	if (!is_root_cache(s) && s->memcg_params->memcg == memcg)

		cache_show(s, m);

	return 0;

	return cache_show(s, m);

}

#endif



/*

 * slabinfo_op - iterator that generates /proc/slabinfo

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