From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44916) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cu0OG-0004tQ-SN for qemu-devel@nongnu.org; Fri, 31 Mar 2017 13:31:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cu0OC-0008HB-8L for qemu-devel@nongnu.org; Fri, 31 Mar 2017 13:31:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35186) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cu0OB-0008GE-Ul for qemu-devel@nongnu.org; Fri, 31 Mar 2017 13:31:08 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C006D3DBD7 for ; Fri, 31 Mar 2017 17:31:06 +0000 (UTC) Date: Fri, 31 Mar 2017 18:31:01 +0100 From: "Richard W.M. Jones" Message-ID: <20170331173101.GL30620@redhat.com> References: <20170331164322.24020-1-stefanha@redhat.com> <4de63a1a-e385-e22f-9bc4-f29d90cbdc30@redhat.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="cNdxnHkX5QqsyA0e" Content-Disposition: inline In-Reply-To: <4de63a1a-e385-e22f-9bc4-f29d90cbdc30@redhat.com> Subject: Re: [Qemu-devel] [PATCH] char: kick main loop after adding a watch List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: Stefan Hajnoczi , qemu-devel@nongnu.org, =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , Frediano Ziglio --cNdxnHkX5QqsyA0e Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Mar 31, 2017 at 06:53:56PM +0200, Paolo Bonzini wrote: > glib is expecting QEMU to use g_main_context_acquire around accesses to > GMainContext. However QEMU is not doing that, instead it is taking its > own mutex. So we should add g_main_context_acquire and > g_main_context_release in the two implementations of > os_host_main_loop_wait; these should undo the effect of Frediano's > glib patch. Based on this paragraph, I'm testing the attached patch, and it does also appear to solve the hanging serial port problem. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org --cNdxnHkX5QqsyA0e Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="0001-main-loop-Acquire-main_context-lock-around-os_host_m.patch" >>From d46afa25dae0f1d057cfac3a0b6ae94771be51f2 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Fri, 31 Mar 2017 18:29:01 +0100 Subject: [PATCH] main-loop: Acquire main_context lock around os_host_main_loop_wait. --- util/main-loop.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/util/main-loop.c b/util/main-loop.c index 4534c89..19cad6b 100644 --- a/util/main-loop.c +++ b/util/main-loop.c @@ -218,9 +218,12 @@ static void glib_pollfds_poll(void) static int os_host_main_loop_wait(int64_t timeout) { + GMainContext *context = g_main_context_default(); int ret; static int spin_counter; + g_main_context_acquire(context); + glib_pollfds_fill(&timeout); /* If the I/O thread is very busy or we are incorrectly busy waiting in @@ -256,6 +259,9 @@ static int os_host_main_loop_wait(int64_t timeout) } glib_pollfds_poll(); + + g_main_context_release(context); + return ret; } #else @@ -412,12 +418,15 @@ static int os_host_main_loop_wait(int64_t timeout) fd_set rfds, wfds, xfds; int nfds; + g_main_context_acquire(context); + /* XXX: need to suppress polling by better using win32 events */ ret = 0; for (pe = first_polling_entry; pe != NULL; pe = pe->next) { ret |= pe->func(pe->opaque); } if (ret != 0) { + g_main_context_release(context); return ret; } @@ -472,6 +481,8 @@ static int os_host_main_loop_wait(int64_t timeout) g_main_context_dispatch(context); } + g_main_context_release(context); + return select_ret || g_poll_ret; } #endif -- 2.9.3 --cNdxnHkX5QqsyA0e--