From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51337) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f8yod-0003IM-9C for qemu-devel@nongnu.org; Wed, 18 Apr 2018 21:56:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f8yoa-0005hS-4n for qemu-devel@nongnu.org; Wed, 18 Apr 2018 21:56:51 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:55124 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 1f8yoZ-0005gv-Uy for qemu-devel@nongnu.org; Wed, 18 Apr 2018 21:56:48 -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 EC8D84023112 for ; Thu, 19 Apr 2018 01:56:38 +0000 (UTC) Date: Thu, 19 Apr 2018 09:56:31 +0800 From: Fam Zheng Message-ID: <20180419015631.GE29462@lemon.usersys.redhat.com> References: <20180418090622.20073-1-peterx@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180418090622.20073-1-peterx@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: Peter Xu Cc: qemu-devel@nongnu.org, Paolo Bonzini , Stefan Hajnoczi 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? > bool initialized; > }; > > diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c > index b789cf32e9..905a816af6 100644 > --- a/util/qemu-thread-posix.c > +++ b/util/qemu-thread-posix.c > @@ -68,6 +68,10 @@ void qemu_mutex_lock_impl(QemuMutex *mutex, const char *file, const int line) > if (err) > error_exit(err, __func__); > > +#ifdef CONFIG_DEBUG_MUTEX > + mutex->file = file; > + mutex->line = line; > +#endif > trace_qemu_mutex_locked(mutex, file, line); > } > > -- > 2.14.3 > Fam