On Fri, 2012-03-09 at 17:27 -0300, Rafael Aquini wrote:
> Following the example at mm/slub.c, add out-of-memory diagnostics to the
> SLAB allocator to help on debugging certain OOM conditions.
>
> An example print out looks like this:
>
> <snip page allocator out-of-memory message>
> SLAB: Unable to allocate memory on node 0 (gfp=0x11200)
> cache: bio-0, object size: 192, order: 0
> node 0: slabs: 3/3, objs: 60/60, free: 0
Should probably be :
node: 0 slabs: 3/3, objs: 60/60, free: 0
>
> Signed-off-by: Rafael Aquini <aquini@xxxxxxxxxx>
> Acked-by: Rik van Riel <riel@xxxxxxxxxx>
> ---
> v2:
> * drop the sysctl knob to override __GFP_NOWARN allocation flag (Pekka, David)
>
> v3:
> * adjust the print output to match slub's warning printout (WANG Cong)
>
> mm/slab.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 50 insertions(+), 1 deletions(-)
>
> diff --git a/mm/slab.c b/mm/slab.c
> index f0bd785..cda1ff6 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -1731,6 +1731,52 @@ static int __init cpucache_init(void)
> }
> __initcall(cpucache_init);
>
> +static noinline void
> +slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
> +{
> + struct kmem_list3 *l3;
> + struct slab *slabp;
> + unsigned long flags;
> + int node;
> +
> + printk(KERN_WARNING
> + "SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
> + nodeid, gfpflags);
> + printk(KERN_WARNING " cache: %s, object size: %d, order: %d\n",
> + cachep->name, cachep->buffer_size, cachep->gfporder);
> +
> + for_each_online_node(node) {
> + unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
> + unsigned long active_slabs = 0, num_slabs = 0;
> +
> + l3 = cachep->nodelists[node];
> + if (!l3)
> + continue;
> +
> + spin_lock_irqsave(&l3->list_lock, flags);
> + list_for_each_entry(slabp, &l3->slabs_full, list) {
> + active_objs += cachep->num;
> + active_slabs++;
> + }
> + list_for_each_entry(slabp, &l3->slabs_partial, list) {
> + active_objs += slabp->inuse;
> + active_slabs++;
> + }
> + list_for_each_entry(slabp, &l3->slabs_free, list)
> + num_slabs++;
> +
> + free_objects += l3->free_objects;
> + spin_unlock_irqrestore(&l3->list_lock, flags);
> +
> + num_slabs += active_slabs;
> + num_objs = num_slabs * cachep->num;
> + printk(KERN_WARNING
> + " node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
Probably should be :
" node: %d slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
> + node, active_slabs, num_slabs, active_objs, num_objs,
> + free_objects);
> + }
> +}
> +
> /*
> * Interface to system's page allocator. No need to hold the cache-lock.
> *
> @@ -1757,8 +1803,11 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
> flags |= __GFP_RECLAIMABLE;
>
> page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
> - if (!page)
> + if (!page) {
> + if (!(flags & __GFP_NOWARN) && printk_ratelimit())
> + slab_out_of_memory(cachep, flags, nodeid);
> return NULL;
> + }
>
> nr_pages = (1 << cachep->gfporder);
> if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>