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[Qemu-devel] [PATCH v7 04/19] replay: don't drain/flush bdrv queue while
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [PATCH v7 04/19] replay: don't drain/flush bdrv queue while RR is working |
Date: |
Wed, 10 Oct 2018 16:33:57 +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 bd9d688..96fb245 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
*/
@@ -538,6 +539,13 @@ 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());
@@ -566,6 +574,13 @@ 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);
@@ -1997,6 +2012,13 @@ 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 1c741bc..d60ddf1 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1078,7 +1078,6 @@ static int do_vm_stop(RunState state, bool send_stop)
}
bdrv_drain_all();
- replay_disable_events();
ret = bdrv_flush_all();
return ret;
@@ -2135,7 +2134,6 @@ int vm_prepare_start(void)
/* We are sending this now, but the CPUs will be resumed shortly later */
qapi_event_send_resume();
- replay_enable_events();
cpu_enable_ticks();
runstate_set(RUN_STATE_RUNNING);
vm_state_notify(1, RUN_STATE_RUNNING);
- [Qemu-devel] [PATCH v7 00/19] Fixing record/replay and adding reverse debugging, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 01/19] block: implement bdrv_snapshot_goto for blkreplay, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 02/19] replay: disable default snapshot for record/replay, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 03/19] replay: update docs for record/replay with block devices, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 04/19] replay: don't drain/flush bdrv queue while RR is working,
Pavel Dovgalyuk <=
- [Qemu-devel] [PATCH v7 05/19] replay: finish record/replay before closing the disks, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 06/19] qcow2: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 07/19] migration: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 08/19] replay: provide and accessor for rr filename, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 09/19] replay: introduce info hmp/qmp command, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 11/19] replay: implement replay-seek command to proceed to the desired step, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 12/19] replay: refine replay-time module, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 13/19] replay: flush rr queue before loading the vmstate, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 10/19] replay: introduce breakpoint at the specified step, Pavel Dovgalyuk, 2018/10/10
- [Qemu-devel] [PATCH v7 14/19] gdbstub: add reverse step support in replay mode, Pavel Dovgalyuk, 2018/10/10