From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933345Ab0ECQdJ (ORCPT ); Mon, 3 May 2010 12:33:09 -0400 Received: from tex.lwn.net ([70.33.254.29]:35324 "EHLO vena.lwn.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933321Ab0ECQdG (ORCPT ); Mon, 3 May 2010 12:33:06 -0400 Date: Mon, 3 May 2010 10:33:00 -0600 From: Jonathan Corbet To: mgross@linux.intel.com Cc: Kevin Hilman , aili@codeaurora.org, dwalker@codeaurora.org, tiwai@suse.de, bruce.w.allan@intel.com, davidb@quicinc.com, mcgrof@gmail.com, pavel@ucw.cz, linux-pm , lkml Subject: Re: [PATCH]PM QOS refresh against next-20100430 Message-ID: <20100503103300.6330e522@bike.lwn.net> In-Reply-To: <20100430212043.GA30315@linux.intel.com> References: <20100430212043.GA30315@linux.intel.com> Organization: LWN.net X-Mailer: Claws Mail 3.7.5 (GTK+ 2.20.0; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 30 Apr 2010 14:20:43 -0700 mark gross wrote: > This patch changes the string based list management to a handle base > implementation to help with the hot path use of pm-qos Having taken a quick look, I think the API change makes a lot of sense. Hot paths are one thing; avoidance of accidental conflicts would be another. One question, though... one clear use of this API is for drivers to say "don't go into C3 or deeper because things go wrong"; I'm about to add another one of those. It works, but the use of a PM_QOS_CPU_DMA_LATENCY requirement with a hard-coded number that one hopes is small enough seems a bit...indirect. I wonder if it would be clearer and more robust to add a new requirement^Wrequest type saying "the quality of service I need is shallow sleeps only"? jon