From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56687) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f901A-0006sc-TL for qemu-devel@nongnu.org; Wed, 18 Apr 2018 23:13:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f9017-0005iw-ND for qemu-devel@nongnu.org; Wed, 18 Apr 2018 23:13:52 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:41698 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f9017-0005iY-Hu for qemu-devel@nongnu.org; Wed, 18 Apr 2018 23:13:49 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D3C6DEB703 for ; Thu, 19 Apr 2018 03:13:43 +0000 (UTC) Date: Thu, 19 Apr 2018 11:13:35 +0800 From: Peter Xu Message-ID: <20180419031335.GH14841@xz-mi> References: <20180418090622.20073-1-peterx@redhat.com> <20180419015631.GE29462@lemon.usersys.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180419015631.GE29462@lemon.usersys.redhat.com> Subject: Re: [Qemu-devel] [PATCH v2] QemuMutex: support --enable-debug-mutex List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng Cc: qemu-devel@nongnu.org, Paolo Bonzini , Stefan Hajnoczi On Thu, Apr 19, 2018 at 09:56:31AM +0800, Fam Zheng wrote: > On Wed, 04/18 17:06, Peter Xu wrote: > > We have had some tracing tools for mutex but it's not easy to use them > > for e.g. dead locks. Let's provide "--enable-debug-mutex" parameter > > when configure to allow QemuMutex to store the last owner that took > > specific lock. It might be extremely easy to use this tool to debug > > deadlocks since we can directly know who took the lock then as long as > > we can have a gdb attached to the process. > > > > CC: Paolo Bonzini > > CC: Stefan Hajnoczi > > CC: Fam Zheng > > Signed-off-by: Peter Xu > > --- > > v2: > > - fix "--disable-debug-mutex" not working.. > > --- > > configure | 10 ++++++++++ > > include/qemu/thread-posix.h | 4 ++++ > > util/qemu-thread-posix.c | 4 ++++ > > 3 files changed, 18 insertions(+) > > > > diff --git a/configure b/configure > > index 0a19b033bc..a80af735b2 100755 > > --- a/configure > > +++ b/configure > > @@ -451,6 +451,7 @@ jemalloc="no" > > replication="yes" > > vxhs="" > > libxml2="" > > +debug_mutex="no" > > > > supported_cpu="no" > > supported_os="no" > > @@ -1374,6 +1375,10 @@ for opt do > > ;; > > --disable-git-update) git_update=no > > ;; > > + --enable-debug-mutex) debug_mutex=yes > > + ;; > > + --disable-debug-mutex) debug_mutex=no > > + ;; > > *) > > echo "ERROR: unknown option $opt" > > echo "Try '$0 --help' for more information" > > @@ -1631,6 +1636,7 @@ disabled with --disable-FEATURE, default is enabled if available: > > crypto-afalg Linux AF_ALG crypto backend driver > > vhost-user vhost-user support > > capstone capstone disassembler support > > + debug-mutex mutex debugging support > > > > NOTE: The object files are built at the place where configure is launched > > EOF > > @@ -5874,6 +5880,7 @@ echo "avx2 optimization $avx2_opt" > > echo "replication support $replication" > > echo "VxHS block device $vxhs" > > echo "capstone $capstone" > > +echo "mutex debugging $debug_mutex" > > > > if test "$sdl_too_old" = "yes"; then > > echo "-> Your SDL version is too old - please upgrade to have SDL support" > > @@ -6602,6 +6609,9 @@ fi > > if test "$capstone" != "no" ; then > > echo "CONFIG_CAPSTONE=y" >> $config_host_mak > > fi > > +if test "$debug_mutex" = "yes" ; then > > + echo "CONFIG_DEBUG_MUTEX=y" >> $config_host_mak > > +fi > > > > # Hold two types of flag: > > # CONFIG_THREAD_SETNAME_BYTHREAD - we've got a way of setting the name on > > diff --git a/include/qemu/thread-posix.h b/include/qemu/thread-posix.h > > index f3f47e426f..fd27b34128 100644 > > --- a/include/qemu/thread-posix.h > > +++ b/include/qemu/thread-posix.h > > @@ -12,6 +12,10 @@ typedef QemuMutex QemuRecMutex; > > > > struct QemuMutex { > > pthread_mutex_t lock; > > +#ifdef CONFIG_DEBUG_MUTEX > > + const char *file; > > + int line; > > +#endif > > These look quite cheap, why we need a configure option to enable it? Yeah; I am not 100% sure about whether it's cheap or not, hence with that. I can remove that part if we are sure we want it always. -- Peter Xu