From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 141E5900149 for ; Wed, 5 Oct 2011 04:08:47 -0400 (EDT) Message-ID: <4E8C1064.3030902@parallels.com> Date: Wed, 5 Oct 2011 12:08:04 +0400 From: Glauber Costa MIME-Version: 1.0 Subject: Re: [PATCH v5 6/8] tcp buffer limitation: per-cgroup limit References: <1317730680-24352-1-git-send-email-glommer@parallels.com> <1317730680-24352-7-git-send-email-glommer@parallels.com> <1317732535.2440.6.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> In-Reply-To: <1317732535.2440.6.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Eric Dumazet Cc: linux-kernel@vger.kernel.org, paul@paulmenage.org, lizf@cn.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com, ebiederm@xmission.com, davem@davemloft.net, gthelen@google.com, netdev@vger.kernel.org, linux-mm@kvack.org, kirill@shutemov.name, avagin@parallels.com, devel@openvz.org On 10/04/2011 04:48 PM, Eric Dumazet wrote: > Le mardi 04 octobre 2011 =C3=A0 16:17 +0400, Glauber Costa a =C3=A9crit : >> This patch uses the "tcp_max_mem" field of the kmem_cgroup to >> effectively control the amount of kernel memory pinned by a cgroup. >> >> We have to make sure that none of the memory pressure thresholds >> specified in the namespace are bigger than the current cgroup. >> >> Signed-off-by: Glauber Costa >> CC: David S. Miller >> CC: Hiroyouki Kamezawa >> CC: Eric W. Biederman >> --- > > >> --- a/include/net/tcp.h >> +++ b/include/net/tcp.h >> @@ -256,6 +256,7 @@ extern int sysctl_tcp_thin_dupack; >> struct mem_cgroup; >> struct tcp_memcontrol { >> /* per-cgroup tcp memory pressure knobs */ >> + int tcp_max_memory; >> atomic_long_t tcp_memory_allocated; >> struct percpu_counter tcp_sockets_allocated; >> /* those two are read-mostly, leave them at the end */ >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > So tcp_max_memory is an "int". > > >> +static u64 tcp_read_limit(struct cgroup *cgrp, struct cftype *cft) >> +{ >> + struct mem_cgroup *memcg =3D mem_cgroup_from_cont(cgrp); >> + return memcg->tcp.tcp_max_memory<< PAGE_SHIFT; >> +} > > 1) Typical integer overflow here. > > You need : > > return ((u64)memcg->tcp.tcp_max_memory)<< PAGE_SHIFT; Thanks for spotting this, Eric. > > 2) Could you add const qualifiers when possible to your pointers ? Well, I'll go over the patches again and see where I can add them. Any specific place site you're concerned about? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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: email@kvack.org