net: decrement memcg jump label when limit, not usage, is changed

The logic of the current code is that whenever we destroy
a cgroup that had its limit set (set meaning different than
maximum), we should decrement the jump_label counter.
Otherwise we assume it was never incremented.

But what the code actually does is test for RES_USAGE
instead of RES_LIMIT. Usage being different than maximum
is likely to be true most of the time.

The effect of this is that the key must become negative,
and since the jump_label test says:

        !!atomic_read(&key->enabled);

we'll have jump_labels still on when no one else is
using this functionality.

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: David S. Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Glauber Costa 2012-01-12 02:16:06 +00:00 committed by David S. Miller
parent cf778b00e9
commit 1398eee082

View File

@ -108,7 +108,7 @@ void tcp_destroy_cgroup(struct cgroup *cgrp, struct cgroup_subsys *ss)
tcp = tcp_from_cgproto(cg_proto);
percpu_counter_destroy(&tcp->tcp_sockets_allocated);
val = res_counter_read_u64(&tcp->tcp_memory_allocated, RES_USAGE);
val = res_counter_read_u64(&tcp->tcp_memory_allocated, RES_LIMIT);
if (val != RESOURCE_MAX)
jump_label_dec(&memcg_socket_limit_enabled);