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[Qemu-devel] [PATCH v3 04/19] replay: don't drain/flush bdrv queue while
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [PATCH v3 04/19] replay: don't drain/flush bdrv queue while RR is working |
Date: |
Wed, 23 May 2018 09:50:05 +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 ca96b48..853d5a4 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
*/
@@ -408,6 +409,13 @@ 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
@@ -459,6 +467,13 @@ 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);
@@ -1841,6 +1856,13 @@ 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 d1f1629..b3bf018 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;
@@ -2063,7 +2062,6 @@ 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 v3 00/19] reverse debugging, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 01/19] block: implement bdrv_snapshot_goto for blkreplay, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 02/19] replay: disable default snapshot for record/replay, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 03/19] replay: update docs for record/replay with block devices, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 04/19] replay: don't drain/flush bdrv queue while RR is working,
Pavel Dovgalyuk <=
- [Qemu-devel] [PATCH v3 05/19] replay: finish record/replay before closing the disks, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 06/19] qcow2: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 07/19] migration: introduce icount field for snapshots, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 08/19] replay: introduce info hmp/qmp command, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 09/19] replay: introduce breakpoint at the specified step, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 10/19] replay: implement replay-seek command to proceed to the desired step, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 11/19] replay: flush events when exiting, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 13/19] replay: refine replay-time module, Pavel Dovgalyuk, 2018/05/23
- [Qemu-devel] [PATCH v3 12/19] timer: remove replay clock probe in deadline calculation, Pavel Dovgalyuk, 2018/05/23