From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751461Ab3LJTyk (ORCPT ); Tue, 10 Dec 2013 14:54:40 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:60161 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751130Ab3LJTyi (ORCPT ); Tue, 10 Dec 2013 14:54:38 -0500 Message-ID: <52A77188.50200@jp.fujitsu.com> Date: Tue, 10 Dec 2013 14:54:48 -0500 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.1.1 MIME-Version: 1.0 To: fweisbec@gmail.com CC: kosaki.motohiro@jp.fujitsu.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@kernel.org, peterz@infradead.org, oleg@redhat.com, akpm@linux-foundation.org Subject: Re: [PATCH 02/10 v2] posix-timers: Remove dead process posix cpu timers caching References: <1386611931-4658-1-git-send-email-fweisbec@gmail.com> In-Reply-To: <1386611931-4658-1-git-send-email-fweisbec@gmail.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (12/9/2013 12:58 PM), Frederic Weisbecker wrote: > Now that we removed dead thread posix cpu timers caching, > lets remove the dead process wide version. This caching > is similar to the per thread version but it should be even > more rare: > > * If the process id dead, we are not reading its timers > status from a thread belonging to its group since they > are all dead. So this caching only concern remote process > timers reads. Now posix cpu timers using itimers or timer_settime() > can't do remote process timers anyway so it's not even clear if there > is actually a user for this caching. > > * Unlike per thread timers caching, this only applies to > zombies targets. Buried targets' process wide timers return > 0 values. But then again, timer_gettime() can't read remote > process timers, so if the process is dead, there can't be > any reader left anyway. > > Then again this caching seem to complicate the code for > corner cases that are probably not worth it. So lets get > rid of it. > > Also remove the sample snapshot on dying process timer > that is now useless, as suggested by Kosaki. > > Signed-off-by: Frederic Weisbecker > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Peter Zijlstra > Cc: Oleg Nesterov > Cc: Kosaki Motohiro > Cc: Andrew Morton Looks good to me. Acked-by: KOSAKI Motohiro