From patchwork Sun Sep 4 14:51:56 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anthony Liguori X-Patchwork-Id: 113277 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 79DAAB6F72 for ; Mon, 5 Sep 2011 00:52:10 +1000 (EST) Received: from localhost ([::1]:47775 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R0E3J-0003G9-Hd for incoming@patchwork.ozlabs.org; Sun, 04 Sep 2011 10:52:05 -0400 Received: from eggs.gnu.org ([140.186.70.92]:37293) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R0E3E-0003G4-8M for qemu-devel@nongnu.org; Sun, 04 Sep 2011 10:52:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R0E3C-0005eX-OO for qemu-devel@nongnu.org; Sun, 04 Sep 2011 10:52:00 -0400 Received: from mail-yw0-f45.google.com ([209.85.213.45]:41155) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R0E3C-0005eT-Ls for qemu-devel@nongnu.org; Sun, 04 Sep 2011 10:51:58 -0400 Received: by ywf9 with SMTP id 9so3311621ywf.4 for ; Sun, 04 Sep 2011 07:51:58 -0700 (PDT) Received: by 10.150.11.7 with SMTP id 7mr1822176ybk.433.1315147918088; Sun, 04 Sep 2011 07:51:58 -0700 (PDT) Received: from [192.168.0.103] (cpe-70-123-132-139.austin.res.rr.com [70.123.132.139]) by mx.google.com with ESMTPS id h12sm6239146anl.5.2011.09.04.07.51.56 (version=TLSv1/SSLv3 cipher=OTHER); Sun, 04 Sep 2011 07:51:57 -0700 (PDT) Message-ID: <4E63908C.4070409@codemonkey.ws> Date: Sun, 04 Sep 2011 09:51:56 -0500 From: Anthony Liguori User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.17) Gecko/20110516 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: Avi Kivity References: <1314018774-27482-1-git-send-email-aliguori@us.ibm.com> <1314018774-27482-2-git-send-email-aliguori@us.ibm.com> <4E63851F.3070205@redhat.com> In-Reply-To: <4E63851F.3070205@redhat.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 209.85.213.45 Cc: Blue Swirl , Paolo Bonzini , qemu-devel@nongnu.org, Kevin Wolf Subject: Re: [Qemu-devel] [PATCH 2/2] main: switch qemu_set_fd_handler to g_io_add_watch X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org On 09/04/2011 09:03 AM, Avi Kivity wrote: > On 08/22/2011 04:12 PM, Anthony Liguori wrote: >> This patch changes qemu_set_fd_handler to be implemented in terms of >> g_io_add_watch(). The semantics are a bit different so some glue is >> required. >> >> qemu_set_fd_handler2 is much harder to convert because of its use of >> polling. >> >> The glib main loop has the major of advantage of having a proven >> thread safe >> architecture. By using the glib main loop instead of our own, it will >> allow us >> to eventually introduce multiple I/O threads. >> >> I'm pretty sure that this will work on Win32, but I would appreciate >> some help >> testing. I think the semantics of g_io_channel_unix_new() are really >> just tied >> to the notion of a "unix fd" and not necessarily unix itself. > > 'git bisect' fingered this as responsible for breaking > qcow2+cache=unsafe. I think there's an off-by-one here and the guilty > patch is the one that switches the main loop, but that's just a guess. Semantically, this patch changes when a file descriptor callback is issued. Does the following make a difference: What type of guest install is it that fails for you and is this qemu-kvm.git or qemu.git? Regards, Anthony Liguori > > The symptoms are that a guest that is restarted (new qemu process) after > install doesn't make it through grub - some image data didn't make it do > disk. With qcow2 and cache=unsafe that can easily happen through exit > notifiers not being run and the entire qcow2 metadata being thrown out > the window. Running with raw+cache=unsafe works. > > >> >> diff --git a/iohandler.c b/iohandler.c >> index 4deae1e..5ef66fb 100644 >> --- a/iohandler.c >> +++ b/iohandler.c >> @@ -80,12 +80,67 @@ int qemu_set_fd_handler2(int fd, >> return 0; >> } >> >> +typedef struct IOTrampoline >> +{ >> + GIOChannel *chan; >> + IOHandler *fd_read; >> + IOHandler *fd_write; >> + void *opaque; >> + guint tag; >> +} IOTrampoline; >> + >> +static gboolean fd_trampoline(GIOChannel *chan, GIOCondition cond, >> gpointer opaque) >> +{ >> + IOTrampoline *tramp = opaque; >> + >> + if (tramp->opaque == NULL) { >> + return FALSE; >> + } >> + >> + if ((cond& G_IO_IN)&& tramp->fd_read) { >> + tramp->fd_read(tramp->opaque); >> + } >> + >> + if ((cond& G_IO_OUT)&& tramp->fd_write) { >> + tramp->fd_write(tramp->opaque); >> + } >> + >> + return TRUE; >> +} >> + >> int qemu_set_fd_handler(int fd, >> IOHandler *fd_read, >> IOHandler *fd_write, >> void *opaque) >> { >> - return qemu_set_fd_handler2(fd, NULL, fd_read, fd_write, opaque); >> + static IOTrampoline fd_trampolines[FD_SETSIZE]; >> + IOTrampoline *tramp =&fd_trampolines[fd]; >> + >> + if (tramp->tag != 0) { >> + g_io_channel_unref(tramp->chan); >> + g_source_remove(tramp->tag); >> + } >> + >> + if (opaque) { >> + GIOCondition cond = 0; >> + >> + tramp->fd_read = fd_read; >> + tramp->fd_write = fd_write; >> + tramp->opaque = opaque; >> + >> + if (fd_read) { >> + cond |= G_IO_IN | G_IO_ERR; >> + } >> + >> + if (fd_write) { >> + cond |= G_IO_OUT | G_IO_ERR; >> + } >> + >> + tramp->chan = g_io_channel_unix_new(fd); >> + tramp->tag = g_io_add_watch(tramp->chan, cond, fd_trampoline, tramp); >> + } >> + >> + return 0; >> } >> >> void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set >> *writefds, fd_set *xfds) > > diff --git a/vl.c b/vl.c index 5ba9b35..02f694d 100644 --- a/vl.c +++ b/vl.c @@ -1432,9 +1432,9 @@ int main_loop_wait(int nonblocking) qemu_mutex_lock_iothread(); } + glib_select_poll(&rfds, &wfds, &xfds, (ret < 0)); qemu_iohandler_poll(&rfds, &wfds, &xfds, ret); slirp_select_poll(&rfds, &wfds, &xfds, (ret < 0)); - glib_select_poll(&rfds, &wfds, &xfds, (ret < 0)); qemu_run_all_timers();