From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1007980-1525279380-2-12951629749732105337 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='US-ASCII' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-api-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1525279380; b=QvUKN5/YDfI9t2VKZVtCMIRLtnwfrdH6Gkf6y+zJF4YF3dy7Lj u0lgC+dwikiJLUqZzs1FnVGwhjks6RTGNuX6Bo391EDEen5B6dIbhY1HVMue7x6j Lb3LLybAleMUBacfvcYl14Bm/29NBtKiukUeJ4SIwZzejRqL1Rm6A4ibctfSUMdo +abEQwhJQFrQ4qMn6yFmddRVnCi+RyolpyMb3JVp7Qb2rpXyeiahVnGqk7CfnJxX G67zH1oaH4vjVzgn9nMT0PUthzG+7qdWDYgK91rBzQlAig7H1vLVzO+oPH3L0snD QNjhi26PMTF0jHdz0MW25Jlvz2vAF945dU0A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :in-reply-to:references:mime-version:content-type :content-transfer-encoding:sender:list-id; s=fm2; t=1525279380; bh=DRV9CxjRn6IPB6qKDISJdxSGBHa3z/Gr02aEjgA9J+M=; b=JOQ9ryTj7k99 OtXNTtMRR3XMGBMlAoKg1dORA/opp4yhW5SxPGPjzT5jtMChUYuQl7tfmZq6kFdR 8PTFDpda5mZ/ubXxsOYmDkRTfmEV7oeX8oot/Uayt0r4XONrsDQoIShFfN8VSRbb 8zM1K/vakFscoFHGkxwAuRdDRb6KMaq7shlGAK0lp6ZV2K8mzzj6qee8sbymiEoa K0hwRLEECeMbrn2gW6DH1TqdZqfIazdMIAORU4BsOqa+tGzWul6Ot/IKXJDZQngd VAa3o/31d8nc36QxeL1LPScYSu0ZjahaNRnC/ALxmZiQ2Lv9U3QztBLJhSGf23me FsmIjks0VQ== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=goodmis.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=goodmis.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=goodmis.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=goodmis.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfDVj8m4JfxtoAMr0LHyM4egoL+p/Ksx3z4fNAHXKQf9JZuAWTkPJCzbkfxX4B7mvDJ9KwWllUslSyhqVXVK/xudZQiduL/UC/BNzo+NZIgV2GNt4ewho atHsSJMnMOYDR38qesjI8sRMJqq46piVO0N7+26vmw9IblfG2FZY2unowJZi4DmSprzrT6FPWCxakHNjHDmLkTWjfWAmXym3fkCKOtocEwXlcGOnHgaWk1M6 X-CM-Analysis: v=2.3 cv=E8HjW5Vl c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=kj9zAlcOel0A:10 a=VUJBJC2UJ8kA:10 a=1XWaLZrsAAAA:8 a=VwQbUJbxAAAA:8 a=fUSZZkATYxXnQMecnGkA:9 a=CjuIK1q_8ugA:10 a=x8gzFH9gYPwA:10 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751525AbeEBQm7 (ORCPT ); Wed, 2 May 2018 12:42:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:56218 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751484AbeEBQm6 (ORCPT ); Wed, 2 May 2018 12:42:58 -0400 Date: Wed, 2 May 2018 12:42:53 -0400 From: Steven Rostedt To: Daniel Colascione Cc: Mathieu Desnoyers , Peter Zijlstra , Paul McKenney , boqun.feng@gmail.com, luto@amacapital.net, davejwatson@fb.com, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Paul Turner , Andrew Morton , linux@arm.linux.org.uk, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, Andrew Hunter , andi@firstfloor.org, cl@linux.com, bmaurer@fb.com, josh@joshtriplett.org, torvalds@linux-foundation.org, catalin.marinas@arm.com, will.deacon@arm.com, Michael Kerrisk-manpages , Joel Fernandes Subject: Re: [RFC PATCH for 4.18 00/14] Restartable Sequences Message-ID: <20180502124253.145253cb@gandalf.local.home> In-Reply-To: References: <20180430224433.17407-1-mathieu.desnoyers@efficios.com> <660904075.9201.1525276988842.JavaMail.zimbra@efficios.com> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, 02 May 2018 16:07:48 +0000 Daniel Colascione wrote: > Why couldn't we take a page fault just before schedule? The reason we can't > take a page fault in atomic context is that doing so might call schedule. > Here, we're about to call schedule _anyway_, so what harm does it do to > call something that might call schedule? If we schedule via that call, we > can skip the manual schedule we were going to perform. Another issue is slowing down something that is considered a fast path. -- Steve