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[Qemu-devel] [PATCH v5 04/24] replay: don't drain/flush bdrv queue while
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [PATCH v5 04/24] replay: don't drain/flush bdrv queue while RR is working |
Date: |
Wed, 25 Jul 2018 15:13:35 +0300 |
User-agent: |
StGit/0.17.1-dirty |
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 <address@hidden>
---
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 7100344..4d7a6e4 100644
--- a/block/io.c
+++ b/block/io.c
@@ -32,6 +32,7 @@
#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
*/
@@ -533,6 +534,13 @@ void bdrv_drain_all_begin(void)
return;
}
+ /* bdrv queue is managed by record/replay,
+ waiting for finishing the I/O requests may
+ be infinite */
+ if (replay_events_enabled()) {
+ return;
+ }
+
/* AIO_WAIT_WHILE() with a NULL context can only be called from the main
* loop AioContext, so make sure we're in the main context. */
assert(qemu_get_current_aio_context() == qemu_get_aio_context());
@@ -561,6 +569,13 @@ void bdrv_drain_all_end(void)
{
BlockDriverState *bs = NULL;
+ /* bdrv queue is managed by record/replay,
+ waiting for finishing the I/O requests may
+ be endless */
+ if (replay_events_enabled()) {
+ return;
+ }
+
while ((bs = bdrv_next_all_states(bs))) {
AioContext *aio_context = bdrv_get_aio_context(bs);
@@ -1993,6 +2008,13 @@ 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 b5844b7..9b98b1f 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1016,7 +1016,6 @@ static int do_vm_stop(RunState state, bool send_stop)
}
bdrv_drain_all();
- replay_disable_events();
ret = bdrv_flush_all();
return ret;
@@ -2067,7 +2066,6 @@ int vm_prepare_start(void)
/* We are sending this now, but the CPUs will be resumed shortly later */
qapi_event_send_resume(&error_abort);
- replay_enable_events();
cpu_enable_ticks();
runstate_set(RUN_STATE_RUNNING);
vm_state_notify(1, RUN_STATE_RUNNING);
- [Qemu-devel] [PATCH v5 00/24] Fixing record/replay and adding reverse debugging, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 01/24] block: implement bdrv_snapshot_goto for blkreplay, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 02/24] replay: disable default snapshot for record/replay, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 03/24] replay: update docs for record/replay with block devices, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 04/24] replay: don't drain/flush bdrv queue while RR is working,
Pavel Dovgalyuk <=
- [Qemu-devel] [PATCH v5 05/24] replay: finish record/replay before closing the disks, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 06/24] qcow2: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 07/24] migration: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 08/24] replay: introduce info hmp/qmp command, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 09/24] replay: introduce breakpoint at the specified step, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 10/24] replay: implement replay-seek command to proceed to the desired step, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 11/24] replay: flush events when exiting, Pavel Dovgalyuk, 2018/07/25
- [Qemu-devel] [PATCH v5 12/24] timer: remove replay clock probe in deadline calculation, Pavel Dovgalyuk, 2018/07/25