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From: Glauber Costa <glommer@parallels.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
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>
Subject: Re: [PATCH v5 6/8] tcp buffer limitation: per-cgroup limit
Date: Thu, 6 Oct 2011 12:38:59 +0400	[thread overview]
Message-ID: <4E8D6923.7080404@parallels.com> (raw)
In-Reply-To: <1317805090.2473.28.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC>

On 10/05/2011 12:58 PM, Eric Dumazet wrote:
> Le mercredi 05 octobre 2011 à 12:08 +0400, Glauber Costa a écrit :
>> On 10/04/2011 04:48 PM, Eric Dumazet wrote:
>
>>> 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?
>
> Everywhere its possible :
>
> It helps reader to instantly knows if a function is about to change some
> part of the object or only read it, without reading function body.
Sure it does.

So, give me your opinion on this:

most of the acessors inside struct sock do not modify the pointers,
but return an address of an element inside it (that can later on be
modified by the caller.

I think it is fine for the purpose of clarity, but to avoid warnings we 
end up having to do stuff like this:

+#define CONSTCG(m) ((struct mem_cgroup *)(m))
+long *tcp_sysctl_mem(const struct mem_cgroup *memcg)
+{
+       return CONSTCG(memcg)->tcp.tcp_prot_mem;
+}

Is it acceptable?

WARNING: multiple messages have this Message-ID (diff)
From: Glauber Costa <glommer@parallels.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
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
Subject: Re: [PATCH v5 6/8] tcp buffer limitation: per-cgroup limit
Date: Thu, 6 Oct 2011 12:38:59 +0400	[thread overview]
Message-ID: <4E8D6923.7080404@parallels.com> (raw)
In-Reply-To: <1317805090.2473.28.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC>

On 10/05/2011 12:58 PM, Eric Dumazet wrote:
> Le mercredi 05 octobre 2011 à 12:08 +0400, Glauber Costa a écrit :
>> On 10/04/2011 04:48 PM, Eric Dumazet wrote:
>
>>> 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?
>
> Everywhere its possible :
>
> It helps reader to instantly knows if a function is about to change some
> part of the object or only read it, without reading function body.
Sure it does.

So, give me your opinion on this:

most of the acessors inside struct sock do not modify the pointers,
but return an address of an element inside it (that can later on be
modified by the caller.

I think it is fine for the purpose of clarity, but to avoid warnings we 
end up having to do stuff like this:

+#define CONSTCG(m) ((struct mem_cgroup *)(m))
+long *tcp_sysctl_mem(const struct mem_cgroup *memcg)
+{
+       return CONSTCG(memcg)->tcp.tcp_prot_mem;
+}

Is it acceptable?

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  reply	other threads:[~2011-10-06  8:39 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-04 12:17 [PATCH v5 0/8] per-cgroup tcp buffer pressure settings Glauber Costa
2011-10-04 12:17 ` Glauber Costa
2011-10-04 12:17 ` [PATCH v5 1/8] Basic kernel memory functionality for the Memory Controller Glauber Costa
2011-10-04 12:17   ` Glauber Costa
2011-10-04 12:17 ` [PATCH v5 2/8] socket: initial cgroup code Glauber Costa
2011-10-04 12:17   ` Glauber Costa
2011-10-04 12:17 ` [PATCH v5 3/8] foundations of per-cgroup memory pressure controlling Glauber Costa
2011-10-04 12:17   ` Glauber Costa
2011-10-04 12:17 ` [PATCH v5 4/8] per-cgroup tcp buffers control Glauber Costa
2011-10-04 12:17   ` Glauber Costa
2011-10-04 12:17 ` [PATCH v5 5/8] per-netns ipv4 sysctl_tcp_mem Glauber Costa
2011-10-04 12:17   ` Glauber Costa
2011-10-04 12:17 ` [PATCH v5 6/8] tcp buffer limitation: per-cgroup limit Glauber Costa
2011-10-04 12:17   ` Glauber Costa
2011-10-04 12:48   ` Eric Dumazet
2011-10-04 12:48     ` Eric Dumazet
2011-10-04 12:48     ` Eric Dumazet
2011-10-05  8:08     ` Glauber Costa
2011-10-05  8:08       ` Glauber Costa
2011-10-05  8:58       ` Eric Dumazet
2011-10-05  8:58         ` Eric Dumazet
2011-10-05  8:58         ` Eric Dumazet
2011-10-06  8:38         ` Glauber Costa [this message]
2011-10-06  8:38           ` Glauber Costa
2011-10-04 12:17 ` [PATCH v5 7/8] Display current tcp memory allocation in kmem cgroup Glauber Costa
2011-10-04 12:17   ` Glauber Costa
2011-10-04 12:18 ` [PATCH v5 8/8] Disable task moving when using kernel memory accounting Glauber Costa
2011-10-04 12:18   ` Glauber Costa
2011-10-05  0:29 ` [PATCH v5 0/8] per-cgroup tcp buffer pressure settings KAMEZAWA Hiroyuki
2011-10-05  0:29   ` KAMEZAWA Hiroyuki
2011-10-05  7:25   ` Glauber Costa
2011-10-05  7:25     ` Glauber Costa
2011-10-05  7:25     ` Glauber Costa
2011-10-07  8:05     ` KAMEZAWA Hiroyuki
2011-10-07  8:05       ` KAMEZAWA Hiroyuki
2011-10-07  8:05       ` KAMEZAWA Hiroyuki
2011-10-07  8:20       ` Glauber Costa
2011-10-07  8:20         ` Glauber Costa
2011-10-07  8:20         ` Glauber Costa
2011-10-07  8:55         ` KAMEZAWA Hiroyuki
2011-10-07  8:55           ` KAMEZAWA Hiroyuki
2011-10-07  8:55           ` KAMEZAWA Hiroyuki

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