From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH 1/4] net: Dynamically allocate the per cpu counters for the loopback device. Date: Thu, 27 Sep 2007 13:56:16 -0700 (PDT) Message-ID: <20070927.135616.37572002.davem@davemloft.net> References: <20070927.115200.56183114.davem@davemloft.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: netdev-owner@vger.kernel.org To: ebiederm@xmission.com Cc: netdev@vger.kernel.org, containers@lists.osdl.org List-Id: containers.vger.kernel.org From: ebiederm@xmission.com (Eric W. Biederman) Date: Thu, 27 Sep 2007 14:44:37 -0600 > David Miller writes: > > > From: ebiederm@xmission.com (Eric W. Biederman) > > Date: Thu, 27 Sep 2007 01:48:00 -0600 > > > >> I'm not doing get_cpu/put_cpu so does the comment make sense > >> in relationship to per_cpu_ptr? > > > > It is possible. But someone would need to go check for > > sure. > > Verified. > > hard_start_xmit is called inside of a > rcu_read_lock_bh(),rcu_read_unlock_bh() pair. Which means > the code will only run on one cpu. > > Therefore we do not need get_cpu/put_cpu. > > In addition per_cpu_ptr is valid. As it is just a lookup > into a NR_CPUS sized array by smp_processor_id() to return > the address of the specific cpu. > > The only difference between per_cpu_ptr and __get_cpu_var() > are the implementation details between statically allocated > and dynamically allocated per cpu state. > > So the comment is still valid, and still interesting it just > should say per_cpu_ptr instead of __get_cpu_var. > > Signed-off-by: "Eric W. Biederman" I've already removed the comment, so you'll have to give me a patch that adds it back with the new content :-)