Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932615AbbGHOkD (ORCPT ); Wed, 8 Jul 2015 10:40:03 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:53303 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1758785AbbGHOkA (ORCPT ); Wed, 8 Jul 2015 10:40:00 -0400 Date: Wed, 8 Jul 2015 10:40:00 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Pavel Machek cc: "Rafael J. Wysocki" , Oliver Neukum , Dave Chinner , Henrique de Moraes Holschuh , Len Brown , Len Brown , One Thousand Gnomes , "linux-kernel@vger.kernel.org" , Linux PM list Subject: Re: [PATCH 1/1] suspend: delete sys_sync() In-Reply-To: <20150708112041.GB29356@amd> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1756 Lines: 46 On Wed, 8 Jul 2015, Pavel Machek wrote: > > well, that depends on what the purpose of the sync is supposed to be. > > > > If it is there to prevent users from corrupting their filesystems as a result > > of a mistake, it is insufficient. If it's there for other reasons, I'm wondering > > what those reasons are (on systems that suspend and resume reliably, because the > > original reason to put it in there was to reduce the damage from suspend/resume > > crashes). > > I put it there, and there were more reasons than "crashes" to put it > there. > > 1) crashes. > > 2) battery is quite likely to run out in suspended machine. > > 3) if someone pulls the stick and puts it in other machine, I wanted > consistent filesystem at least after journal replay. I was going to make the same points. >From my point of view, whether to issue a sync is a tradeoff. I can't remember any time in the last several years where lack of a sync would have caused a problem for my computers, but the possibility still exists. So on one hand, issuing the sync can help prevent a low-probability problem. On the other hand, issuing the sync takes a small amount of time (negligible for my purposes but not negligible for Len and others). I prefer to pay a very small cost to prevent a low-probability problem. Others may not want to pay, because to them the cost is larger or the probability is lower. _That_ is the justification for not eliminating the sync completely but making it optional. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/