From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [ANNOUNCE] Native Linux KVM tool v2 Date: Thu, 16 Jun 2011 13:40:45 +0200 Message-ID: <20110616114045.GA27060@elte.hu> References: <4DF935C1.4020000@codemonkey.ws> <20110616092429.GA5484@infradead.org> <20110616094810.GA19965@infradead.org> <20110616100239.GA29262@infradead.org> <20110616112230.GD26110@elte.hu> <20110616112552.GA15816@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Pekka Enberg , Anthony Liguori , Alexander Graf , Prasad Joshi , Avi Kivity , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Andrew Morton , Linus Torvalds , Sasha Levin , Cyrill Gorcunov , Asias He , Jens Axboe To: Christoph Hellwig Return-path: Received: from mx2.mail.elte.hu ([157.181.151.9]:50419 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752422Ab1FPLk5 (ORCPT ); Thu, 16 Jun 2011 07:40:57 -0400 Content-Disposition: inline In-Reply-To: <20110616112552.GA15816@infradead.org> Sender: kvm-owner@vger.kernel.org List-ID: * Christoph Hellwig wrote: > On Thu, Jun 16, 2011 at 01:22:30PM +0200, Ingo Molnar wrote: > > Such as? I don't think apps can actually know whether disk blocks > > have been 'instantiated' by a particular filesystem or not, so > > the manpage: > > In general they can't. The only good use case for sync_file_range > is to paper over^H^H^H^H^H^H^H^H^Hcontrol write back behaviour. Well, if overwrite is fundamentally safe on a filesystem (which is most of them) then sync_file_range() would work - and it has the big advantage that it's a pretty simple facility. Filesystems that cannot guarantee that should map their sync_file_range() implementation to fdatasync() or so, right? Thanks, Ingo