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=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 1D3A0C4338F for ; Mon, 26 Jul 2021 12:55:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F13EE60F46 for ; Mon, 26 Jul 2021 12:55:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234262AbhGZMOv (ORCPT ); Mon, 26 Jul 2021 08:14:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:50476 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234072AbhGZMOu (ORCPT ); Mon, 26 Jul 2021 08:14:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id CC70B60F45; Mon, 26 Jul 2021 12:55:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627304119; bh=dF3bcYVZjrToiiFeynXBJaQUeLiCWZ2ycIVhBM/7cL4=; h=From:To:Cc:Subject:Date:From; b=h+GTM4yIgwK7NwN1rE9GFXzg5B63lX7ZvCdKFiw4ub1TGEwwiLNeqGtGV2tnQ7KkM xWEXnsGhhvzbmFGi6mOiAeFjX7EYyo4jm9G4SzuOwtIH/8W64JDg4edfHxbUv8as5N nUSBVAn2na5FuRFE9Iucu5R0JGbSq42bnECdBKyiCAA+TkIWG09OiarCd7CX0YaEcY iW/xkwnGTXLWTSA2WKnMJT3bsJXRE9ifh+59xXlvzp1QiQU3kOcwqS8Kkp+9SV3gf9 5sO92cumcM3pg3bZa7JGLCYPIaGW1ckQ4xRWkt0NWVc6OOr3HJKhrsDZkKbE3OInFD 4RLQk7rjTRR8A== From: Frederic Weisbecker To: Thomas Gleixner , Ingo Molnar Cc: LKML , Frederic Weisbecker , Peter Zijlstra , "Eric W . Biederman" , Oleg Nesterov Subject: [GIT PULL] posix-cpu-timers leftover overhead fixes Date: Mon, 26 Jul 2021 14:55:07 +0200 Message-Id: <20210726125513.271824-1-frederic@kernel.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thomas, Ingo, Please pull the timers/core branch that can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git timers/core HEAD: 63a17eea7d5516f9e927fdc52b45f1d040fdcf35 --- Those are not regression fixes since these bugs precede the git-era, therefore they are not carrying a stable tag. Several posix cpu timers events (setting, deletion, expiration) may end up leaving needless elapsing overhead after a timer has stopped or even after it has been deleted. Those overhead are: 1) Costly process wide cputime accounting that rely on concurrent atomic addition during tick or even more frequent scheduler internal stat updates. 2) Retained tick dependency on NOHZ_FULL configurations. Hopefully this series gets rid of all the possible culprits. Thanks, Frederic --- Frederic Weisbecker (6): posix-cpu-timers: Assert task sighand is locked while starting cputime counter posix-cpu-timers: Force next_expiration recalc after timer deletion posix-cpu-timers: Force next expiration recalc after itimer reset posix-cpu-timers: Remove confusing error code override posix-cpu-timers: Consolidate timer base accessor posix-cpu-timers: Recalc next expiration when timer_settime() ends up not queueing include/linux/posix-timers.h | 11 +++++- include/linux/sched/signal.h | 6 +++ kernel/signal.c | 15 +++++++ kernel/time/posix-cpu-timers.c | 90 ++++++++++++++++++++++++++++++++++-------- 4 files changed, 103 insertions(+), 19 deletions(-)