On 02/22/2012 03:35 AM, Suleiman Souhlal wrote:

On Tue, Feb 21, 2012 at 3:34 AM, Glauber Costa[off-list ref]  wrote:

quoted

@@ -5055,8 +5117,21 @@ int memcg_kmem_newpage(struct mem_cgroup *memcg, struct page *page, unsigned lon
  {
        unsigned long size = pages<<  PAGE_SHIFT;
        struct res_counter *fail;
+       int ret;
+       bool do_softlimit;
+
+       ret = res_counter_charge(memcg_kmem(memcg), size,&fail);
+       if (unlikely(mem_cgroup_event_ratelimit(memcg,
+                                               MEM_CGROUP_TARGET_THRESH))) {
+
+               do_softlimit = mem_cgroup_event_ratelimit(memcg,
+                                               MEM_CGROUP_TARGET_SOFTLIMIT);
+               mem_cgroup_threshold(memcg);
+               if (unlikely(do_softlimit))
+                       mem_cgroup_update_tree(memcg, page);
+       }

-       return res_counter_charge(memcg_kmem(memcg), size,&fail);
+       return ret;
  }

It seems like this might cause a lot of kernel memory allocations to
fail whenever we are at the limit, even if we have a lot of
reclaimable memory, when we don't have independent accounting.

Would it be better to use __mem_cgroup_try_charge() here, when we
don't have independent accounting, in order to deal with this
situation?

Yes, it would.
I'll work on that.