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replay: flush rr queue before loading the vmstate

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Non-empty record/replay queue prevents saving and loading the VM state,
because it includes pending bottom halves and block coroutines.
But when the new VM state is loaded, we don't have to preserve the consistency
of the current state anymore. Therefore this patch just flushes the queue
allowing the coroutines to finish and removes checking for empty rr queue
for load_snapshot function.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <160174521762.12451.15752448887893855757.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Pavel Dovgalyuk 2020-10-03 20:13:37 +03:00 committed by Paolo Bonzini
parent f6baed3d14
commit f9a9fb6516
4 changed files with 12 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/sysemu/replay.h
View File

@ -149,6 +149,8 @@ void replay_disable_events(void);
void replay_enable_events(void); void replay_enable_events(void);
/*! Returns true when saving events is enabled */ /*! Returns true when saving events is enabled */
bool replay_events_enabled(void); bool replay_events_enabled(void);
/* Flushes events queue */
void replay_flush_events(void);
/*! Adds bottom half event to the queue */ /*! Adds bottom half event to the queue */
void replay_bh_schedule_event(QEMUBH *bh); void replay_bh_schedule_event(QEMUBH *bh);
/* Adds oneshot bottom half event to the queue */ /* Adds oneshot bottom half event to the queue */

12
migration/savevm.c
View File

@ -2881,12 +2881,6 @@ int load_snapshot(const char *name, Error **errp)
AioContext *aio_context; AioContext *aio_context;
MigrationIncomingState *mis = migration_incoming_get_current(); MigrationIncomingState *mis = migration_incoming_get_current();
if (!replay_can_snapshot()) {
error_setg(errp, "Record/replay does not allow loading snapshot "
"right now. Try once more later.");
return -EINVAL;
}
if (!bdrv_all_can_snapshot(&bs)) { if (!bdrv_all_can_snapshot(&bs)) {
error_setg(errp, error_setg(errp,
"Device '%s' is writable but does not support snapshots", "Device '%s' is writable but does not support snapshots",
@ -2920,6 +2914,12 @@ int load_snapshot(const char *name, Error **errp)
return -EINVAL; return -EINVAL;
} }
/*
* Flush the record/replay queue. Now the VM state is going
* to change. Therefore we don't need to preserve its consistency
*/
replay_flush_events();
/* Flush all IO requests so they don't interfere with the new state. */ /* Flush all IO requests so they don't interfere with the new state. */
bdrv_drain_all_begin(); bdrv_drain_all_begin();

4
replay/replay-events.c
View File

@ -77,6 +77,10 @@ bool replay_has_events(void)
void replay_flush_events(void) void replay_flush_events(void)
{ {
if (replay_mode == REPLAY_MODE_NONE) {
return;
}
g_assert(replay_mutex_locked()); g_assert(replay_mutex_locked());
while (!QTAILQ_EMPTY(&events_list)) { while (!QTAILQ_EMPTY(&events_list)) {

2
replay/replay-internal.h
View File

@ -149,8 +149,6 @@ void replay_read_next_clock(unsigned int kind);
void replay_init_events(void); void replay_init_events(void);
/*! Clears internal data structures for events handling */ /*! Clears internal data structures for events handling */
void replay_finish_events(void); void replay_finish_events(void);
/*! Flushes events queue */
void replay_flush_events(void);
/*! Returns true if there are any unsaved events in the queue */ /*! Returns true if there are any unsaved events in the queue */
bool replay_has_events(void); bool replay_has_events(void);
/*! Saves events from queue into the file */ /*! Saves events from queue into the file */