mm, slub: print CPU id (and its node) on slab OOM

Depending on how remote_node_defrag_ratio is configured, allocations can
end up in this path as a result of the local node being OOM, despite the
allocation overall being unconstrained (node == -1).

When we print a warning, printing the current CPU makes that situation
more clear (i.e., you can immediately see which node's OOM status
matters for the allocation at hand).

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

diff --git a/mm/slub.c b/mm/slub.c
index c9d8a2497fd65e1f48cd933a67bf75ab8f9c117b..3088260bf75d437f3f3593a7a7398272f26745d7 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3416,14 +3416,15 @@ slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
 {
        static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
                                      DEFAULT_RATELIMIT_BURST);
+       int cpu = raw_smp_processor_id();
        int node;
        struct kmem_cache_node *n;
 
        if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
                return;
 
-       pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
-               nid, gfpflags, &gfpflags);
+       pr_warn("SLUB: Unable to allocate memory on CPU %u (of node %d) on node %d, gfp=%#x(%pGg)\n",
+               cpu, cpu_to_node(cpu), nid, gfpflags, &gfpflags);
        pr_warn("  cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
                s->name, s->object_size, s->size, oo_order(s->oo),
                oo_order(s->min));