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Commit 9a02d699 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

mm, slab: suppress out of memory warning unless debug is enabled 



When the slab or slub allocators cannot allocate additional slab pages,
they emit diagnostic information to the kernel log such as current
number of slabs, number of objects, active objects, etc.  This is always
coupled with a page allocation failure warning since it is controlled by
!__GFP_NOWARN.

Suppress this out of memory warning if the allocator is configured
without debug supported.  The page allocation failure warning will
indicate it is a failed slab allocation, the order, and the gfp mask, so
this is only useful to diagnose allocator issues.

Since CONFIG_SLUB_DEBUG is already enabled by default for the slub
allocator, there is no functional change with this patch.  If debug is
disabled, however, the warnings are now suppressed.

Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ecc42fbe

mm/slab.c

+8 −2
Original line number Diff line number Diff line
@@ -1621,10 +1621,16 @@ __initcall(cpucache_init); 
static noinline void

slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)

{

#if DEBUG

	struct kmem_cache_node *n;

	struct page *page;

	unsigned long flags;

	int node;

	static DEFINE_RATELIMIT_STATE(slab_oom_rs, DEFAULT_RATELIMIT_INTERVAL,

				      DEFAULT_RATELIMIT_BURST);



	if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slab_oom_rs))

		return;



	printk(KERN_WARNING

		"SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
@@ -1662,6 +1668,7 @@ slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid) 
			node, active_slabs, num_slabs, active_objs, num_objs,

			free_objects);

	}

#endif

}



/*
@@ -1683,7 +1690,6 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, 


	page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);

	if (!page) {

		if (!(flags & __GFP_NOWARN) && printk_ratelimit())

		slab_out_of_memory(cachep, flags, nodeid);

		return NULL;

	}

mm/slub.c

+17 −12
Original line number Diff line number Diff line
@@ -2119,11 +2119,19 @@ static inline int node_match(struct page *page, int node) 
	return 1;

}



#ifdef CONFIG_SLUB_DEBUG

static int count_free(struct page *page)

{

	return page->objects - page->inuse;

}



static inline unsigned long node_nr_objs(struct kmem_cache_node *n)

{

	return atomic_long_read(&n->total_objects);

}

#endif /* CONFIG_SLUB_DEBUG */



#if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)

static unsigned long count_partial(struct kmem_cache_node *n,

					int (*get_count)(struct page *))

{
@@ -2137,21 +2145,19 @@ static unsigned long count_partial(struct kmem_cache_node *n, 
	spin_unlock_irqrestore(&n->list_lock, flags);

	return x;

}



static inline unsigned long node_nr_objs(struct kmem_cache_node *n)

{

#ifdef CONFIG_SLUB_DEBUG

	return atomic_long_read(&n->total_objects);

#else

	return 0;

#endif

}

#endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */



static noinline void

slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)

{

#ifdef CONFIG_SLUB_DEBUG

	static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,

				      DEFAULT_RATELIMIT_BURST);

	int node;



	if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))

		return;



	pr_warn("SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",

		nid, gfpflags);

	pr_warn("  cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n",
@@ -2178,6 +2184,7 @@ slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) 
		pr_warn("  node %d: slabs: %ld, objs: %ld, free: %ld\n",

			node, nr_slabs, nr_objs, nr_free);

	}

#endif

}



static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
@@ -2356,9 +2363,7 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, 
	freelist = new_slab_objects(s, gfpflags, node, &c);



	if (unlikely(!freelist)) {

		if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())

		slab_out_of_memory(s, gfpflags, node);



		local_irq_restore(flags);

		return NULL;

	}