Re: [PATCH v4 4/8] per-cgroup tcp buffers control

On Mon,  3 Oct 2011 14:18:39 +0400
Glauber Costa [off-list ref] wrote:

With all the infrastructure in place, this patch implements
per-cgroup control for tcp memory pressure handling.

Signed-off-by: Glauber Costa <redacted>
CC: David S. Miller <davem@davemloft.net>
CC: Hiroyouki Kamezawa <redacted>
CC: Eric W. Biederman <redacted>

Reviewed-by: KAMEZAWA Hiroyuki <redacted>

One question.

+void tcp_enter_memory_pressure(struct sock *sk)
+{
+	struct mem_cgroup *memcg = sk->sk_cgrp;
+	if (!memcg->tcp.tcp_memory_pressure) {
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
+		memcg->tcp.tcp_memory_pressure = 1;
+	}
+}

It seems memcg->tcp.tcp_memory_pressure has no locks and not atomic.

no problematic race ?

Thanks,
-Kame

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