From: Peter Lieven <p...@kamp.de>
the current implementation submits up to 512 I/O requests in parallel
which is much to high especially for a background task.
This patch adds a maximum limit of 16 I/O requests that can
be submitted in parallel to avoid monopolizing the I/O device.
Signed-off-by: Peter Lieven <p...@kamp.de>
Message-Id: <1520507908-16743-5-git-send-email...@kamp.de>
Reviewed-by: Juan Quintela <quint...@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
migration/block.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/migration/block.c b/migration/block.c
index 5c03632257..03bbba61cb 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -37,6 +37,7 @@
#define MAX_IS_ALLOCATED_SEARCH (65536 * BDRV_SECTOR_SIZE)
#define MAX_IO_BUFFERS 512
+#define MAX_PARALLEL_IO 16
//#define DEBUG_BLK_MIGRATION
@@ -775,6 +776,7 @@ static int block_save_iterate(QEMUFile *f, void *opaque)
while ((block_mig_state.submitted +
block_mig_state.read_done) * BLOCK_SIZE <
qemu_file_get_rate_limit(f) &&
+ block_mig_state.submitted < MAX_PARALLEL_IO &&
(block_mig_state.submitted + block_mig_state.read_done) <
MAX_IO_BUFFERS) {
blk_mig_unlock();
--
2.14.3
