From: Zhi Yong Wu <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Zhi Yong Wu <[email protected]>
Reviewed-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>
---
block.c | 20 ++++++++++++++++++++
1 files changed, 20 insertions(+), 0 deletions(-)
diff --git a/block.c b/block.c
index 8858be0..0344673 100644
--- a/block.c
+++ b/block.c
@@ -1463,6 +1463,17 @@ static int bdrv_rw_co(BlockDriverState *bs, int64_t
sector_num, uint8_t *buf,
qemu_iovec_init_external(&qiov, &iov, 1);
+ /**
+ * In sync call context, when the vcpu is blocked, this throttling timer
+ * will not fire; so the I/O throttling function has to be disabled here
+ * if it has been enabled.
+ */
+ if (bs->io_limits_enabled) {
+ fprintf(stderr, "Disabling I/O throttling on '%s' due "
+ "to synchronous I/O.\n", bdrv_get_device_name(bs));
+ bdrv_io_limits_disable(bs);
+ }
+
if (qemu_in_coroutine()) {
/* Fast-path if already in coroutine context */
bdrv_rw_co_entry(&rwco);
@@ -1969,10 +1980,19 @@ static int guess_disk_lchs(BlockDriverState *bs,
struct partition *p;
uint32_t nr_sects;
uint64_t nb_sectors;
+ bool enabled;
bdrv_get_geometry(bs, &nb_sectors);
+ /**
+ * The function will be invoked during startup not only in sync I/O mode,
+ * but also in async I/O mode. So the I/O throttling function has to
+ * be disabled temporarily here, not permanently.
+ */
+ enabled = bs->io_limits_enabled;
+ bs->io_limits_enabled = false;
ret = bdrv_read(bs, 0, buf, 1);
+ bs->io_limits_enabled = enabled;
if (ret < 0)
return -1;
/* test msdos magic */
--
1.7.6.5
