[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-block] [PULL 12/13] vl: Drain before (block) job cancel when quitt

From: Kevin Wolf
Subject: [Qemu-block] [PULL 12/13] vl: Drain before (block) job cancel when quitting
Date: Fri, 19 Jul 2019 15:43:44 +0200

From: Max Reitz <address@hidden>

If the main loop cancels all block jobs while the block layer is not
drained, this cancelling may not happen instantaneously.  We can start a
drained section before vm_shutdown(), which entails another
bdrv_drain_all(); this nested bdrv_drain_all() will thus be a no-op,

We do not have to end the drained section, because we actually do not
want any requests to happen from this point on.

Signed-off-by: Max Reitz <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
 vl.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/vl.c b/vl.c
index a5808f9a02..53335a5470 100644
--- a/vl.c
+++ b/vl.c
@@ -4480,6 +4480,17 @@ int main(int argc, char **argv, char **envp)
+    /*
+     * We must cancel all block jobs while the block layer is drained,
+     * or cancelling will be affected by throttling and thus may block
+     * for an extended period of time.
+     * vm_shutdown() will bdrv_drain_all(), so we may as well include
+     * it in the drained section.
+     * We do not need to end this section, because we do not want any
+     * requests happening from here on anyway.
+     */
+    bdrv_drain_all_begin();
     /* No more vcpu or device emulation activity beyond this point */

reply via email to

[Prev in Thread] Current Thread [Next in Thread]