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[Qemu-devel] [RFC PATCH v5 24/24] replay: don't drain/flush bdrv queue w
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [RFC PATCH v5 24/24] replay: don't drain/flush bdrv queue while RR is working |
Date: |
Tue, 23 Jan 2018 11:55:33 +0300 |
User-agent: |
StGit/0.17.1-dirty |
In record/replay mode bdrv queue is controlled by replay mechanism.
It does not allow stopping the vm, saving or loading the snapshots
when bdrv queue is not empty. Therefore draining and flushing is unnecessary
(and may cause deadlocks in replay mode).
This patch disables bdrv_drain_all and bdrv_flush_all in 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 7ea4023..e773e68 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 a1f8808..e84f041 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1005,7 +1005,6 @@ static int do_vm_stop(RunState state)
}
bdrv_drain_all();
- replay_disable_events();
ret = bdrv_flush_all();
return ret;
@@ -1988,7 +1987,6 @@ 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] [RFC PATCH v5 14/24] replay/replay.c: bump REPLAY_VERSION again, (continued)
- [Qemu-devel] [RFC PATCH v5 14/24] replay/replay.c: bump REPLAY_VERSION again, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 15/24] replay/replay-internal.c: track holding of replay_lock, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 16/24] replay: make locking visible outside replay code, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 17/24] replay: push replay_mutex_lock up the call tree, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 18/24] replay: don't destroy mutex at exit, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 19/24] replay: check return values of fwrite, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 20/24] replay: avoid recursive call of checkpoints, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 22/24] replay: don't process async events when warping the clock, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 21/24] scripts/replay-dump.py: replay log dumper, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 23/24] replay: save vmstate of the asynchronous events, Pavel Dovgalyuk, 2018/01/23
- [Qemu-devel] [RFC PATCH v5 24/24] replay: don't drain/flush bdrv queue while RR is working,
Pavel Dovgalyuk <=
- Re: [Qemu-devel] [RFC PATCH v5 00/24] replay additions, no-reply, 2018/01/23
- Re: [Qemu-devel] [RFC PATCH v5 00/24] replay additions, Pavel Dovgalyuk, 2018/01/30