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[Qemu-devel] [PATCH v7 20/22] replay: don't drain/flush bdrv queue while
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [PATCH v7 20/22] replay: don't drain/flush bdrv queue while RR is working |
Date: |
Tue, 27 Feb 2018 12:53:27 +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 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);
- [Qemu-devel] [PATCH v7 11/22] replay/replay-internal.c: track holding of replay_lock, (continued)
- [Qemu-devel] [PATCH v7 11/22] replay/replay-internal.c: track holding of replay_lock, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 10/22] replay/replay.c: bump REPLAY_VERSION again, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 12/22] replay: make locking visible outside replay code, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 13/22] replay: push replay_mutex_lock up the call tree, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 14/22] replay: don't destroy mutex at exit, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 15/22] replay: check return values of fwrite, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 16/22] replay: avoid recursive call of checkpoints, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 17/22] scripts/replay-dump.py: replay log dumper, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 18/22] replay: don't process async events when warping the clock, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 19/22] replay: save vmstate of the asynchronous events, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 20/22] replay: don't drain/flush bdrv queue while RR is working,
Pavel Dovgalyuk <=
- [Qemu-devel] [PATCH v7 21/22] replay: update documentation, Pavel Dovgalyuk, 2018/02/27
- [Qemu-devel] [PATCH v7 22/22] tcg: fix cpu_io_recompile, Pavel Dovgalyuk, 2018/02/27