From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52590) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d6acQ-0001ld-Ko for qemu-devel@nongnu.org; Fri, 05 May 2017 06:37:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d6acP-0006kX-K1 for qemu-devel@nongnu.org; Fri, 05 May 2017 06:37:50 -0400 Received: from mail-wm0-x230.google.com ([2a00:1450:400c:c09::230]:38077) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1d6acP-0006iW-Ej for qemu-devel@nongnu.org; Fri, 05 May 2017 06:37:49 -0400 Received: by mail-wm0-x230.google.com with SMTP id 142so2195248wma.1 for ; Fri, 05 May 2017 03:37:49 -0700 (PDT) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Fri, 5 May 2017 11:38:18 +0100 Message-Id: <20170505103822.20641-6-alex.bennee@linaro.org> In-Reply-To: <20170505103822.20641-1-alex.bennee@linaro.org> References: <20170505103822.20641-1-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [RFC PATCH v1 5/9] replay: make locking visible outside replay code List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: pbonzini@redhat.com, boost.lists@gmail.com, pavel.dovgaluk@ispras.ru Cc: cota@braap.org, qemu-devel@nongnu.org, =?UTF-8?q?Alex=20Benn=C3=A9e?= The replay_mutex_lock/unlock/locked functions are now going to be used for ensuring lock-step behaviour between the two threads. Make them public API functions and also provide stubs for non-QEMU builds on common paths. Signed-off-by: Alex Bennée --- include/sysemu/replay.h | 14 ++++++++++++++ replay/replay-internal.c | 5 ++--- replay/replay-internal.h | 5 ++--- stubs/replay.c | 15 +++++++++++++++ 4 files changed, 33 insertions(+), 6 deletions(-) diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h index f1c0712795..08bffa2dc2 100644 --- a/include/sysemu/replay.h +++ b/include/sysemu/replay.h @@ -46,6 +46,20 @@ extern ReplayMode replay_mode; /* Name of the initial VM snapshot */ extern char *replay_snapshot; +/* Replay locking + * + * The locks are needed to protect the shared structures and log file + * when doing record/replay. They also are the main sync-point between + * the main-loop thread and the vCPU thread. This was a role + * previously filled by the BQL which has been busy trying to reduce + * its impact across the code. This ensures blocks of events stay + * sequential and reproducible. + */ + +void replay_mutex_lock(void); +void replay_mutex_unlock(void); +bool replay_mutex_locked(void); + /* Replay process control functions */ /*! Enables recording or saving event log with specified parameters */ diff --git a/replay/replay-internal.c b/replay/replay-internal.c index 157c863e25..e6b2fdb6c1 100644 --- a/replay/replay-internal.c +++ b/replay/replay-internal.c @@ -181,7 +181,7 @@ void replay_mutex_destroy(void) static __thread bool replay_locked; -static bool replay_mutex_locked(void) +bool replay_mutex_locked(void) { return replay_locked; } @@ -204,7 +204,7 @@ void replay_mutex_unlock(void) void replay_save_instructions(void) { if (replay_file && replay_mode == REPLAY_MODE_RECORD) { - replay_mutex_lock(); + g_assert(replay_mutex_locked()); int diff = (int)(replay_get_current_step() - replay_state.current_step); /* Time can only go forward */ @@ -215,6 +215,5 @@ void replay_save_instructions(void) replay_put_dword(diff); replay_state.current_step += diff; } - replay_mutex_unlock(); } } diff --git a/replay/replay-internal.h b/replay/replay-internal.h index ed66ed803c..b0cf78f16f 100644 --- a/replay/replay-internal.h +++ b/replay/replay-internal.h @@ -97,12 +97,11 @@ int64_t replay_get_qword(void); void replay_get_array(uint8_t *buf, size_t *size); void replay_get_array_alloc(uint8_t **buf, size_t *size); -/* Mutex functions for protecting replay log file */ +/* Mutex functions for protecting replay log file and ensuring + * synchronisation between vCPU and main-loop threads. */ void replay_mutex_init(void); void replay_mutex_destroy(void); -void replay_mutex_lock(void); -void replay_mutex_unlock(void); /*! Checks error status of the file. */ void replay_check_error(void); diff --git a/stubs/replay.c b/stubs/replay.c index 9c8aa48c9c..39c5746043 100644 --- a/stubs/replay.c +++ b/stubs/replay.c @@ -72,3 +72,18 @@ uint64_t blkreplay_next_id(void) { return 0; } + +void replay_mutex_lock(void) +{ + abort(); +} + +void replay_mutex_unlock(void) +{ + abort(); +} + +bool replay_mutex_locked(void) +{ + return false; +} -- 2.11.0