From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60971) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WXs6F-0006V2-JO for qemu-devel@nongnu.org; Wed, 09 Apr 2014 08:59:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WXs6A-0001oP-Gp for qemu-devel@nongnu.org; Wed, 09 Apr 2014 08:59:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33461) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WXs6A-0001oG-8P for qemu-devel@nongnu.org; Wed, 09 Apr 2014 08:59:26 -0400 Date: Wed, 9 Apr 2014 13:59:19 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20140409125918.GE2584@work-vm> References: <1396967377-6311-1-git-send-email-dgilbert@redhat.com> <20140408160811.GA2505@work-vm> <20140409115837.GD2584@work-vm> <6E9C1B08-A777-43F8-9D31-9ACA633E689B@icloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6E9C1B08-A777-43F8-9D31-9ACA633E689B@icloud.com> Subject: Re: [Qemu-devel] [PATCH v4 1/1] Make qemu_peek_buffer loop until it gets it's data List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: ???? Cc: armbru@redhat.com, qemu-devel@nongnu.org, quintela@redhat.com * ???? (chenliang0016@icloud.com) wrote: > > > * ???? (chenliang0016@icloud.com) wrote: > >> > >>> * ???? (chenliang0016@icloud.com) wrote: > >>>> > >>>> ?? 2014??4??8????????10:29??Dr. David Alan Gilbert (git) ?????? > >>>> > >>>>> From: "Dr. David Alan Gilbert" > >>>>> > >>>>> Make qemu_peek_buffer repeatedly call fill_buffer until it gets > >>>>> all the data it requires, or until there is an error. > >>>>> > >>>>> At the moment, qemu_peek_buffer will try one qemu_fill_buffer if there > >>>>> isn't enough data waiting, however the kernel is entitled to return > >>>>> just a few bytes, and still leave qemu_peek_buffer with less bytes > >>>>> than it needed. I've seen this fail in a dev world, and I think it > >>>>> could theoretically fail in the peeking of the subsection headers in > >>>>> the current world. > >>>> hmm, I also have got some errors(infrequently). Maybe It is one point. > >>>> Could you show some messages about the error? > >>> > >>> I've only seen the errors in my visitor/ber world where I use the peek_buffer > >>> a lot more; but the one place it is used in the existing code is in > >>> the code to check if we have the start of a subsection; if that goes wrong > >>> I'm not sure what error would be produced. > >>> > >>> Dave > >> In my observation, error is more likely to happen if migration thread is blocked too long. > >> BTW, xbzrle and auto convergence are disable. > > > > What error do you see? > > > > Dave > It likes section id 1 load failed at dest side. Our migration errors aren't particularly descriptive :-( However, try it with this patch - I'd be interested if it makes your problem go away. Dave -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK