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[Qemu-devel] [RFC PATCH v6 16/20] replay: avoid recursive call of checkp
From: |
Pavel Dovgalyuk |
Subject: |
[Qemu-devel] [RFC PATCH v6 16/20] replay: avoid recursive call of checkpoints |
Date: |
Wed, 07 Feb 2018 15:05:23 +0300 |
User-agent: |
StGit/0.17.1-dirty |
This patch adds a flag which denies recursive call of replay_checkpoint
function. Checkpoints may be accompanied by the hardware events. When event
is processed, virtual device may invoke timer modification functions that
also invoke the checkpoint function. This leads to infinite loop.
Signed-off-by: Pavel Dovgalyuk <address@hidden>
---
replay/replay.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/replay/replay.c b/replay/replay.c
index 585c5de..c676dd4 100644
--- a/replay/replay.c
+++ b/replay/replay.c
@@ -176,13 +176,24 @@ void replay_shutdown_request(ShutdownCause cause)
bool replay_checkpoint(ReplayCheckpoint checkpoint)
{
bool res = false;
+ static bool in_checkpoint;
assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST);
- replay_save_instructions();
if (!replay_file) {
return true;
}
+ if (in_checkpoint) {
+ /* If we are already in checkpoint, then there is no need
+ for additional synchronization.
+ Recursion occurs when HW event modifies timers.
+ Timer modification may invoke the checkpoint and
+ proceed to recursion. */
+ return true;
+ }
+ in_checkpoint = true;
+
+ replay_save_instructions();
if (replay_mode == REPLAY_MODE_PLAY) {
g_assert(replay_mutex_locked());
@@ -204,6 +215,7 @@ bool replay_checkpoint(ReplayCheckpoint checkpoint)
res = true;
}
out:
+ in_checkpoint = false;
return res;
}
- [Qemu-devel] [RFC PATCH v6 06/20] replay: fixed replay_enable_events, (continued)
- [Qemu-devel] [RFC PATCH v6 06/20] replay: fixed replay_enable_events, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 07/20] replay: fix save/load vm for non-empty queue, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 08/20] replay: added replay log format description, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 09/20] replay: save prior value of the host clock, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 10/20] replay/replay.c: bump REPLAY_VERSION again, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 11/20] replay/replay-internal.c: track holding of replay_lock, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 12/20] replay: make locking visible outside replay code, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 13/20] replay: push replay_mutex_lock up the call tree, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 14/20] replay: don't destroy mutex at exit, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 15/20] replay: check return values of fwrite, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 16/20] replay: avoid recursive call of checkpoints,
Pavel Dovgalyuk <=
- [Qemu-devel] [RFC PATCH v6 18/20] replay: don't process async events when warping the clock, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 19/20] replay: save vmstate of the asynchronous events, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 17/20] scripts/replay-dump.py: replay log dumper, Pavel Dovgalyuk, 2018/02/07
- [Qemu-devel] [RFC PATCH v6 20/20] replay: don't drain/flush bdrv queue while RR is working, Pavel Dovgalyuk, 2018/02/07
- Re: [Qemu-devel] [RFC PATCH v6 00/20] replay additions, Ciro Santilli, 2018/02/07