From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54273) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ecSHr-0001dA-Nc for qemu-devel@nongnu.org; Fri, 19 Jan 2018 03:44:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ecSHq-0005jE-Ql for qemu-devel@nongnu.org; Fri, 19 Jan 2018 03:44:35 -0500 Received: from mail.ispras.ru ([83.149.199.45]:53798) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ecSHq-0005j5-DU for qemu-devel@nongnu.org; Fri, 19 Jan 2018 03:44:34 -0500 From: Pavel Dovgalyuk Date: Fri, 19 Jan 2018 11:44:37 +0300 Message-ID: <20180119084437.7100.91521.stgit@pasha-VirtualBox> In-Reply-To: <20180119084235.7100.98318.stgit@pasha-VirtualBox> References: <20180119084235.7100.98318.stgit@pasha-VirtualBox> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [RFC PATCH v4 16/23] replay: make locking visible outside replay code List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, boost.lists@gmail.com, quintela@redhat.com, jasowang@redhat.com, mst@redhat.com, zuban32s@gmail.com, maria.klimushenkova@ispras.ru, dovgaluk@ispras.ru, kraxel@redhat.com, pavel.dovgaluk@ispras.ru, pbonzini@redhat.com, alex.bennee@linaro.org From: Alex Benn=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 Benn=C3=A9e Tested-by: Pavel Dovgalyuk --- include/sysemu/replay.h | 14 ++++++++++++++ replay/replay-internal.c | 9 ++++----- replay/replay-internal.h | 5 ++--- stubs/replay.c | 15 +++++++++++++++ 4 files changed, 35 insertions(+), 8 deletions(-) diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h index b86d6bb..9973849 100644 --- a/include/sysemu/replay.h +++ b/include/sysemu/replay.h @@ -47,6 +47,20 @@ extern ReplayMode replay_mode; /* Name of the initial VM snapshot */ extern char *replay_snapshot; =20 +/* 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 */ =20 /*! Enables recording or saving event log with specified parameters */ diff --git a/replay/replay-internal.c b/replay/replay-internal.c index 157c863..a9a6a64 100644 --- a/replay/replay-internal.c +++ b/replay/replay-internal.c @@ -169,6 +169,8 @@ void replay_finish_event(void) replay_fetch_data_kind(); } =20 +static __thread bool replay_locked; + void replay_mutex_init(void) { qemu_mutex_init(&lock); @@ -179,9 +181,7 @@ void replay_mutex_destroy(void) qemu_mutex_destroy(&lock); } =20 -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 =3D=3D REPLAY_MODE_RECORD) { - replay_mutex_lock(); + g_assert(replay_mutex_locked()); int diff =3D (int)(replay_get_current_step() - replay_state.curr= ent_step); =20 /* Time can only go forward */ @@ -215,6 +215,5 @@ void replay_save_instructions(void) replay_put_dword(diff); replay_state.current_step +=3D diff; } - replay_mutex_unlock(); } } diff --git a/replay/replay-internal.h b/replay/replay-internal.h index 8e4c701..f5f8e96 100644 --- a/replay/replay-internal.h +++ b/replay/replay-internal.h @@ -100,12 +100,11 @@ 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); =20 -/* Mutex functions for protecting replay log file */ +/* Mutex functions for protecting replay log file and ensuring + * synchronisation between vCPU and main-loop threads. */ =20 void replay_mutex_init(void); void replay_mutex_destroy(void); -void replay_mutex_lock(void); -void replay_mutex_unlock(void); =20 /*! Checks error status of the file. */ void replay_check_error(void); diff --git a/stubs/replay.c b/stubs/replay.c index 9991ee5..cb050ef 100644 --- a/stubs/replay.c +++ b/stubs/replay.c @@ -73,3 +73,18 @@ 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; +}