From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757462Ab2DEAKR (ORCPT ); Wed, 4 Apr 2012 20:10:17 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44364 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757399Ab2DEAKP (ORCPT ); Wed, 4 Apr 2012 20:10:15 -0400 Date: Wed, 4 Apr 2012 17:10:13 -0700 From: Andrew Morton To: Dmitry Antipov Cc: Thomas Gleixner , linux-kernel@vger.kernel.org, linaro-dev@lists.linaro.org, patches@linaro.org, linux-man@vger.kernel.org Subject: Re: [RFC PATCH] hrtimers: system-wide and per-task hrtimer slacks Message-Id: <20120404171013.ac08575d.akpm@linux-foundation.org> In-Reply-To: <1329724172-27690-1-git-send-email-dmitry.antipov@linaro.org> References: <1329724172-27690-1-git-send-email-dmitry.antipov@linaro.org> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 20 Feb 2012 11:49:32 +0400 Dmitry Antipov wrote: > This patch proposes a system-wide sysctl-aware default for the > high-resolution timer slack value, which may be changed from 0 > to HRTIMER_MAX_SLACK nanoseconds. Default system-wide and per-task > values are HRTIMER_DEFAULT_SLACK. Per-task value isn't inherited > across fork(); instead, newborn task uses system-wide value by > default, and newborn thread uses it's group leader value. Well.. there are some back-incompatibilities here. prctl(PR_SET_TIMERSLACK, -1) used to restore current's slack setting to whatever-we-inherited-at-fork, but that has been removed. What are the implications of this, and did we need to do it? If we do make changes in this area then the prctl manpage should be updated, please. And if http://www.spinics.net/lists/linux-man/msg01149.html represents the current state of that manpage then it should be updated anyway - that entry doesn't say anything about the (arg2 <= 0) case.