From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A3D3C3A59E for ; Wed, 21 Aug 2019 19:33:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 653BB20679 for ; Wed, 21 Aug 2019 19:33:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730563AbfHUTdA (ORCPT ); Wed, 21 Aug 2019 15:33:00 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:57158 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729858AbfHUTas (ORCPT ); Wed, 21 Aug 2019 15:30:48 -0400 Received: from localhost ([127.0.0.1] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1i0WJh-0004A5-Q7; Wed, 21 Aug 2019 21:30:45 +0200 Message-Id: <20190821192919.869350319@linutronix.de> User-Agent: quilt/0.65 Date: Wed, 21 Aug 2019 21:08:54 +0200 From: Thomas Gleixner To: LKML Cc: Oleg Nesterov , Ingo Molnar , Peter Zijlstra , John Stultz , Frederic Weisbecker , Anna-Maria Behnsen , Christoph Hellwig Subject: [patch V2 07/38] posix-cpu-timers: Rename thread_group_cputimer() and make it static References: <20190821190847.665673890@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org thread_group_cputimer() is a complete misnomer. The function does two things: - For arming process wide timers it makes sure that the atomic time storage is up to date. If no cpu timer is armed yet, then the atomic time storage is not updated by the scheduler for performance reasons. In that case a full summing up of all threads needs to be done and the update needs to be enabled. - Samples the current time into the caller supplied storage. Rename it to thread_group_start_cputime(), make it static and fixup the callsite. Signed-off-by: Thomas Gleixner --- include/linux/sched/cputime.h | 1 - kernel/time/posix-cpu-timers.c | 17 +++++++++++++++-- 2 files changed, 15 insertions(+), 3 deletions(-) --- a/include/linux/sched/cputime.h +++ b/include/linux/sched/cputime.h @@ -61,7 +61,6 @@ extern void cputime_adjust(struct task_c * Thread group CPU time accounting. */ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times); -void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times); void thread_group_sample_cputime(struct task_struct *tsk, struct task_cputime *times); /* --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -253,7 +253,20 @@ void thread_group_sample_cputime(struct sample_cputime_atomic(times, &cputimer->cputime_atomic); } -void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times) +/** + * thread_group_start_cputime - Start cputime and return a sample + * @tsk: Task for which cputime needs to be started + * @iimes: Storage for time samples + * + * The thread group cputime accouting is avoided when there are no posix + * CPU timers armed. Before starting a timer it's required to check whether + * the time accounting is active. If not, a full update of the atomic + * accounting store needs to be done and the accounting enabled. + * + * Updates @times with an uptodate sample of the thread group cputimes. + */ +static void +thread_group_start_cputime(struct task_struct *tsk, struct task_cputime *times) { struct thread_group_cputimer *cputimer = &tsk->signal->cputimer; struct task_cputime sum; @@ -536,7 +549,7 @@ static int cpu_timer_sample_group(const { struct task_cputime cputime; - thread_group_cputimer(p, &cputime); + thread_group_start_cputime(p, &cputime); switch (CPUCLOCK_WHICH(which_clock)) { default: return -EINVAL;