From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Glauber Costa <glommer@parallels.com>
Cc: Greg Thelen <gthelen@google.com>,
linux-kernel@vger.kernel.org, paul@paulmenage.org,
lizf@cn.fujitsu.com, ebiederm@xmission.com, davem@davemloft.net,
netdev@vger.kernel.org, linux-mm@kvack.org, kirill@shutemov.name
Subject: Re: [PATCH v3 6/7] tcp buffer limitation: per-cgroup limit
Date: Mon, 26 Sep 2011 20:02:47 +0900 [thread overview]
Message-ID: <20110926200247.c80f7e47.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <4E7DDB82.3030802@parallels.com>
On Sat, 24 Sep 2011 10:30:42 -0300
Glauber Costa <glommer@parallels.com> wrote:
> On 09/22/2011 03:01 AM, Greg Thelen wrote:
> > On Sun, Sep 18, 2011 at 5:56 PM, Glauber Costa<glommer@parallels.com> wrote:
> >> +static inline bool mem_cgroup_is_root(struct mem_cgroup *mem)
> >> +{
> >> + return (mem == root_mem_cgroup);
> >> +}
> >> +
> >
> > Why are you adding a copy of mem_cgroup_is_root(). I see one already
> > in v3.0. Was it deleted in a previous patch?
>
> Already answered by another good samaritan.
>
> >> +static int tcp_write_maxmem(struct cgroup *cgrp, struct cftype *cft, u64 val)
> >> +{
> >> + struct mem_cgroup *sg = mem_cgroup_from_cont(cgrp);
> >> + struct mem_cgroup *parent = parent_mem_cgroup(sg);
> >> + struct net *net = current->nsproxy->net_ns;
> >> + int i;
> >> +
> >> + if (!cgroup_lock_live_group(cgrp))
> >> + return -ENODEV;
> >
> > Why is cgroup_lock_live_cgroup() needed here? Does it protect updates
> > to sg->tcp_prot_mem[*]?
> >
> >> +static u64 tcp_read_maxmem(struct cgroup *cgrp, struct cftype *cft)
> >> +{
> >> + struct mem_cgroup *sg = mem_cgroup_from_cont(cgrp);
> >> + u64 ret;
> >> +
> >> + if (!cgroup_lock_live_group(cgrp))
> >> + return -ENODEV;
> >
> > Why is cgroup_lock_live_cgroup() needed here? Does it protect updates
> > to sg->tcp_max_memory?
>
> No, that is not my understanding. My understanding is this lock is
> needed to protect against the cgroup just disappearing under our nose.
>
Hm. reference count of dentry for cgroup isn't enough ?
Thanks,
-Kame
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next prev parent reply other threads:[~2011-09-26 11:03 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-19 0:56 [PATCH v3 0/7] per-cgroup tcp buffer pressure settings Glauber Costa
2011-09-19 0:56 ` [PATCH v3 1/7] Basic kernel memory functionality for the Memory Controller Glauber Costa
2011-09-21 2:23 ` Glauber Costa
2011-09-22 3:17 ` Balbir Singh
2011-09-22 3:19 ` Glauber Costa
2011-09-24 14:43 ` Glauber Costa
2011-09-27 10:06 ` Balbir Singh
2011-09-22 5:58 ` Greg Thelen
2011-09-26 10:34 ` KAMEZAWA Hiroyuki
2011-09-26 22:44 ` Glauber Costa
2011-09-26 23:18 ` Glauber Costa
2011-09-28 0:58 ` KAMEZAWA Hiroyuki
2011-09-28 12:03 ` Glauber Costa
2011-09-19 0:56 ` [PATCH v3 2/7] socket: initial cgroup code Glauber Costa
2011-09-21 18:47 ` Greg Thelen
2011-09-21 18:59 ` Glauber Costa
2011-09-22 6:00 ` Greg Thelen
2011-09-22 15:09 ` Balbir Singh
2011-09-24 13:33 ` Glauber Costa
2011-09-24 13:40 ` Glauber Costa
2011-09-24 14:45 ` Glauber Costa
2011-09-26 10:52 ` KAMEZAWA Hiroyuki
2011-09-26 22:47 ` Glauber Costa
2011-09-28 0:56 ` KAMEZAWA Hiroyuki
2011-09-27 20:43 ` Glauber Costa
2011-09-19 0:56 ` [PATCH v3 3/7] foundations of per-cgroup memory pressure controlling Glauber Costa
2011-09-19 0:56 ` [PATCH v3 4/7] per-cgroup tcp buffers control Glauber Costa
2011-09-26 10:59 ` KAMEZAWA Hiroyuki
2011-09-26 22:48 ` Glauber Costa
2011-09-27 1:53 ` Glauber Costa
2011-09-28 1:09 ` KAMEZAWA Hiroyuki
2011-09-26 14:39 ` Andrew Vagin
2011-09-26 22:52 ` Glauber Costa
2011-09-19 0:56 ` [PATCH v3 5/7] per-netns ipv4 sysctl_tcp_mem Glauber Costa
2011-09-19 0:56 ` [PATCH v3 6/7] tcp buffer limitation: per-cgroup limit Glauber Costa
2011-09-22 6:01 ` Greg Thelen
2011-09-22 9:58 ` Kirill A. Shutemov
2011-09-22 15:44 ` Greg Thelen
2011-09-24 13:30 ` Glauber Costa
2011-09-26 11:02 ` KAMEZAWA Hiroyuki [this message]
2011-09-26 22:49 ` Glauber Costa
2011-09-22 23:08 ` Balbir Singh
2011-09-24 13:35 ` Glauber Costa
2011-09-24 16:58 ` Andi Kleen
2011-09-24 17:27 ` Glauber Costa
2011-09-28 2:29 ` Balbir Singh
2011-09-28 3:06 ` Andi Kleen
2011-09-19 0:56 ` [PATCH v3 7/7] Display current tcp memory allocation in kmem cgroup Glauber Costa
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