From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38060) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d6EhB-0007zP-7u for qemu-devel@nongnu.org; Thu, 04 May 2017 07:13:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d6Eh7-0002tE-9J for qemu-devel@nongnu.org; Thu, 04 May 2017 07:13:17 -0400 Received: from mail.ispras.ru ([83.149.199.45]:57354) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d6Eh6-0002sk-SD for qemu-devel@nongnu.org; Thu, 04 May 2017 07:13:13 -0400 From: "Pavel Dovgalyuk" References: <20170504084135.7488.24715.stgit@PASHA-ISP> <20170504084210.7488.37561.stgit@PASHA-ISP> In-Reply-To: Date: Thu, 4 May 2017 14:13:15 +0300 Message-ID: <000401d2c4c7$6d5b6d50$481247f0$@ru> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Language: ru Subject: Re: [Qemu-devel] [PATCH v9 06/10] replay: fix save/load vm for non-empty queue List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: 'Paolo Bonzini' , 'Pavel Dovgalyuk' , qemu-devel@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, mst@redhat.com, jasowang@redhat.com, quintela@redhat.com, kraxel@redhat.com > From: Paolo Bonzini [mailto:pbonzini@redhat.com] > On 04/05/2017 10:42, Pavel Dovgalyuk wrote: > > From: Pavel Dovgalyuk > > > > This patch does not allows saving/loading vmstate when > > replay events queue is not empty. There is no reliable > > way to save events queue, because it describes internal > > coroutine state. Therefore saving and loading operations > > should be deferred to another record/replay step. > > Can it actually be non-empty after bdrv_drain_all? drain/flush cannot succeed, because started requests are prisoned in the replay events queue. > > Signed-off-by: Pavel Dovgalyuk > > --- > > include/sysemu/replay.h | 3 +++ > > migration/savevm.c | 13 +++++++++++++ > > replay/replay-snapshot.c | 6 ++++++ > > 3 files changed, 22 insertions(+) > > > > diff --git a/include/sysemu/replay.h b/include/sysemu/replay.h > > index f1c0712795..5c9db2a2ef 100644 > > --- a/include/sysemu/replay.h > > +++ b/include/sysemu/replay.h > > @@ -164,5 +164,8 @@ void replay_audio_in(int *recorded, void *samples, int *wpos, int size); > > /*! Called at the start of execution. > > Loads or saves initial vmstate depending on execution mode. */ > > void replay_vmstate_init(void); > > +/*! Called to ensure that replay state is consistent and VM snapshot > > + can be created */ > > +bool replay_can_snapshot(void); > > > > #endif > > diff --git a/migration/savevm.c b/migration/savevm.c > > index 03ae1bdeb4..358d22170d 100644 > > --- a/migration/savevm.c > > +++ b/migration/savevm.c > > @@ -54,6 +54,7 @@ > > #include "qemu/cutils.h" > > #include "io/channel-buffer.h" > > #include "io/channel-file.h" > > +#include "sysemu/replay.h" > > > > #ifndef ETH_P_RARP > > #define ETH_P_RARP 0x8035 > > @@ -2083,6 +2084,12 @@ int save_vmstate(Monitor *mon, const char *name) > > Error *local_err = NULL; > > AioContext *aio_context; > > > > + if (!replay_can_snapshot()) { > > + monitor_printf(mon, "Record/replay does not allow making snapshot right now. " > > + "Try stopping at another step.\n"); > > + return ret; > > + } > > + > > if (!bdrv_all_can_snapshot(&bs)) { > > monitor_printf(mon, "Device '%s' is writable but does not " > > "support snapshots.\n", bdrv_get_device_name(bs)); > > @@ -2244,6 +2251,12 @@ int load_vmstate(const char *name) > > AioContext *aio_context; > > MigrationIncomingState *mis = migration_incoming_get_current(); > > > > + if (!replay_can_snapshot()) { > > + error_report("Record/replay does not allow loading snapshot right now. " > > + "Try stopping at another step.\n"); > > + return -EINVAL; > > + } > > + > > if (!bdrv_all_can_snapshot(&bs)) { > > error_report("Device '%s' is writable but does not support snapshots.", > > bdrv_get_device_name(bs)); > > diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c > > index 65e2d375c2..438d82ec33 100644 > > --- a/replay/replay-snapshot.c > > +++ b/replay/replay-snapshot.c > > @@ -76,3 +76,9 @@ void replay_vmstate_init(void) > > } > > } > > } > > + > > +bool replay_can_snapshot(void) > > +{ > > + return replay_mode == REPLAY_MODE_NONE > > + || !replay_has_events(); > > +} > > Pavel Dovgalyuk