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[Qemu-block] [PATCH 1/3] block: count bdrv_co_rw_vmstate() requests
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-block] [PATCH 1/3] block: count bdrv_co_rw_vmstate() requests |
Date: |
Wed, 17 May 2017 18:09:39 +0100 |
Call bdrv_inc/dec_in_flight() for vmstate reads/writes. This seems
unnecessary at first glance because vmstate reads/writes are done
synchronously while the guest is stopped. But we need the bdrv_wakeup()
in bdrv_dec_in_flight() so the main loop sees request completion.
Besides, it's cleaner to count vmstate reads/writes like ordinary
read/write requests.
The bdrv_wakeup() partially fixes a 'savevm' hang with -object iothread.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block/io.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/block/io.c b/block/io.c
index fdd7485..cc56e90 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1988,17 +1988,24 @@ bdrv_co_rw_vmstate(BlockDriverState *bs, QEMUIOVector
*qiov, int64_t pos,
bool is_read)
{
BlockDriver *drv = bs->drv;
+ int ret = -ENOTSUP;
+
+ bdrv_inc_in_flight(bs);
if (!drv) {
- return -ENOMEDIUM;
+ ret = -ENOMEDIUM;
} else if (drv->bdrv_load_vmstate) {
- return is_read ? drv->bdrv_load_vmstate(bs, qiov, pos)
- : drv->bdrv_save_vmstate(bs, qiov, pos);
+ if (is_read) {
+ ret = drv->bdrv_load_vmstate(bs, qiov, pos);
+ } else {
+ ret = drv->bdrv_save_vmstate(bs, qiov, pos);
+ }
} else if (bs->file) {
- return bdrv_co_rw_vmstate(bs->file->bs, qiov, pos, is_read);
+ ret = bdrv_co_rw_vmstate(bs->file->bs, qiov, pos, is_read);
}
- return -ENOTSUP;
+ bdrv_dec_in_flight(bs);
+ return ret;
}
static void coroutine_fn bdrv_co_rw_vmstate_entry(void *opaque)
--
2.9.3
[Qemu-block] [PATCH 3/3] migration: avoid recursive AioContext locking in save_vmstate(), Stefan Hajnoczi, 2017/05/17