From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964859AbbJHPuO (ORCPT ); Thu, 8 Oct 2015 11:50:14 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:34267 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933645AbbJHPuM (ORCPT ); Thu, 8 Oct 2015 11:50:12 -0400 Date: Thu, 8 Oct 2015 17:50:06 +0200 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Len Brown , Oliver Neukum , "Rafael J. Wysocki" , "Brown, Len" , Austin S Hemmelgarn , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/1] suspend: make sync() on suspend-to-RAM optional Message-ID: <20151008155006.GB11776@xo-6d-61-c0.localdomain> References: <1436927091-32520-1-git-send-email-lenb@kernel.org> <1437555322.5445.2.camel@suse.com> <1708156.vTh2kYamEW@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1708156.vTh2kYamEW@vostro.rjw.lan> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat 2015-08-01 01:56:19, Rafael J. Wysocki wrote: > On Friday, July 31, 2015 12:02:36 PM Len Brown wrote: > > On Wed, Jul 22, 2015 at 4:55 AM, Oliver Neukum wrote: > > > On Wed, 2015-07-22 at 03:25 +0200, Rafael J. Wysocki wrote: > > >> And it is more pain for me to change the user space on each of them to > > >> write to the new sysfs file on every boot than to set a kernel Kconfig > > >> option once. > > > > > > So why at all? If you really need this in sysfs, why not write > > > something like "memfast" into /sys/power/state ? > > > > We fought this battle, and lost. > > > > When we came out with "freeze", which is faster than "mem", > > no user-space changed to take advantage of it. > > I do think that Chrome is going to use "freeze", so maybe it's not a lost > battle after all? > > The problem with "memfast" and similar things is we'd also need "freezefast" > and "standbyfast" then, for consistency if nothing else, which makes a little > sense to me. > > BTW, it should be noted that the whole "sync in the kernel is better, because > it doesn't race with user space writing to disks" argument was completely > bogus and useless, because in fact the sync in the kernel is done before > freezing user space and which means that it is susceptible to the very same > race condition as the sync from user space. That seems like a bug to me... when did that start happening? I'm pretty sure it was originally done after freeze... -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html