| Message ID | 20180227095327.1060.50979.stgit@pasha-VirtualBox |
|---|---|
| State | New |
| Headers | show |
| Series | replay additions | expand |
On 27/02/2018 10:53, Pavel Dovgalyuk wrote: > In record/replay mode bdrv queue is controlled by replay mechanism. > It does not allow saving or loading the snapshots > when bdrv queue is not empty. Stopping the VM is not blocked by nonempty > queue, but flushing the queue is still impossible there, > because it may cause deadlocks in replay mode. > This patch disables bdrv_drain_all and bdrv_flush_all in > record/replay mode. > > Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> A lot of monitor commands that use bdrv_drain_all are going to remain broken, so I'm not sure about this patch. (There have been many threads about bdrv_drain and bdrv_drain_all being a bad API...). I'm queuing everything except 2-3-4-20. Thanks Pavel and Ciro. Paolo > --- > block/io.c | 22 ++++++++++++++++++++++ > cpus.c | 2 -- > 2 files changed, 22 insertions(+), 2 deletions(-) > > diff --git a/block/io.c b/block/io.c > index 89d0745..a0fd54f 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -31,6 +31,7 @@ > #include "qemu/cutils.h" > #include "qapi/error.h" > #include "qemu/error-report.h" > +#include "sysemu/replay.h" > > #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ > > @@ -407,6 +408,13 @@ void bdrv_drain_all_begin(void) > BdrvNextIterator it; > GSList *aio_ctxs = NULL, *ctx; > > + /* bdrv queue is managed by record/replay, > + waiting for finishing the I/O requests may > + be infinite */ > + if (replay_events_enabled()) { > + return; > + } > + > /* BDRV_POLL_WHILE() for a node can only be called from its own I/O thread > * or the main loop AioContext. We potentially use BDRV_POLL_WHILE() on > * nodes in several different AioContexts, so make sure we're in the main > @@ -458,6 +466,13 @@ void bdrv_drain_all_end(void) > BlockDriverState *bs; > BdrvNextIterator it; > > + /* bdrv queue is managed by record/replay, > + waiting for finishing the I/O requests may > + be endless */ > + if (replay_events_enabled()) { > + return; > + } > + > for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { > AioContext *aio_context = bdrv_get_aio_context(bs); > > @@ -1839,6 +1854,13 @@ int bdrv_flush_all(void) > BlockDriverState *bs = NULL; > int result = 0; > > + /* bdrv queue is managed by record/replay, > + creating new flush request for stopping > + the VM may break the determinism */ > + if (replay_events_enabled()) { > + return result; > + } > + > for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { > AioContext *aio_context = bdrv_get_aio_context(bs); > int ret; > diff --git a/cpus.c b/cpus.c > index 40ed0e6..83e022e 100644 > --- a/cpus.c > +++ b/cpus.c > @@ -1006,7 +1006,6 @@ static int do_vm_stop(RunState state) > } > > bdrv_drain_all(); > - replay_disable_events(); > ret = bdrv_flush_all(); > > return ret; > @@ -2054,7 +2053,6 @@ int vm_prepare_start(void) > qapi_event_send_stop(&error_abort); > res = -1; > } else { > - replay_enable_events(); > cpu_enable_ticks(); > runstate_set(RUN_STATE_RUNNING); > vm_state_notify(1, RUN_STATE_RUNNING); >
diff --git a/block/io.c b/block/io.c index 89d0745..a0fd54f 100644 --- a/block/io.c +++ b/block/io.c @@ -31,6 +31,7 @@ #include "qemu/cutils.h" #include "qapi/error.h" #include "qemu/error-report.h" +#include "sysemu/replay.h" #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ @@ -407,6 +408,13 @@ void bdrv_drain_all_begin(void) BdrvNextIterator it; GSList *aio_ctxs = NULL, *ctx; + /* bdrv queue is managed by record/replay, + waiting for finishing the I/O requests may + be infinite */ + if (replay_events_enabled()) { + return; + } + /* BDRV_POLL_WHILE() for a node can only be called from its own I/O thread * or the main loop AioContext. We potentially use BDRV_POLL_WHILE() on * nodes in several different AioContexts, so make sure we're in the main @@ -458,6 +466,13 @@ void bdrv_drain_all_end(void) BlockDriverState *bs; BdrvNextIterator it; + /* bdrv queue is managed by record/replay, + waiting for finishing the I/O requests may + be endless */ + if (replay_events_enabled()) { + return; + } + for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { AioContext *aio_context = bdrv_get_aio_context(bs); @@ -1839,6 +1854,13 @@ int bdrv_flush_all(void) BlockDriverState *bs = NULL; int result = 0; + /* bdrv queue is managed by record/replay, + creating new flush request for stopping + the VM may break the determinism */ + if (replay_events_enabled()) { + return result; + } + for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { AioContext *aio_context = bdrv_get_aio_context(bs); int ret; diff --git a/cpus.c b/cpus.c index 40ed0e6..83e022e 100644 --- a/cpus.c +++ b/cpus.c @@ -1006,7 +1006,6 @@ static int do_vm_stop(RunState state) } bdrv_drain_all(); - replay_disable_events(); ret = bdrv_flush_all(); return ret; @@ -2054,7 +2053,6 @@ int vm_prepare_start(void) qapi_event_send_stop(&error_abort); res = -1; } else { - replay_enable_events(); cpu_enable_ticks(); runstate_set(RUN_STATE_RUNNING); vm_state_notify(1, RUN_STATE_RUNNING);
In record/replay mode bdrv queue is controlled by replay mechanism. It does not allow saving or loading the snapshots when bdrv queue is not empty. Stopping the VM is not blocked by nonempty queue, but flushing the queue is still impossible there, because it may cause deadlocks in replay mode. This patch disables bdrv_drain_all and bdrv_flush_all in record/replay mode. Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru> --- block/io.c | 22 ++++++++++++++++++++++ cpus.c | 2 -- 2 files changed, 22 insertions(+), 2 deletions(-)