block-migration: limit the memory usage
PATCH 1/1 block-migration: limit the memory usage
If we set migration speed in a very large value, block-migration will try to read all data to the memory. Because
(block_mig_state.submitted + block_mig_state.read_done) * BLOCK_SIZE
will be overflow, and it will be always less than rate limit.
There is no need to read too many data into memory when the rate limit is very large. So limit the memory usage can fix the overflow problem.
--- migration/block.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
migration/block.c +6 -1
@@ -36,6 +36,8 @@#define MAX_IS_ALLOCATED_SEARCH 65536 +#define MAX_INFLIGHT_IO 512 +//#define DEBUG_BLK_MIGRATION #ifdef DEBUG_BLK_MIGRATION
@@ -665,7 +667,10 @@ static int block_save_iterate(QEMUFile *f, void *opaque)blk_mig_lock ();while ((block_mig_state.submitted + block_mig_state.read_done) *BLOCK_SIZE < -qemu_file_get_rate_limit (f)) { +qemu_file_get_rate_limit (f) && + (block_mig_state.submitted + + block_mig_state.read_done) < +MAX_INFLIGHT_IO ) {blk_mig_unlock ();if (block_mig_state.bulk_completed ==0 ) {/* first finish the bulk phase */
Signature · 1 line
2.5.0
Quoted 9 lines · Wen Congyang
If we set migration speed in a very large value, block-migration will try to read all data to the memory. Because
(block_mig_state.submitted + block_mig_state.read_done) *BLOCK_SIZE
will be overflow, and it will be always less than rate limit.There is no need to read too many data into memory when the rate limit is very large. So limit the memory usage can fix the overflow problem.
Signed-off-by Wen Congyang <[email protected]>
If no block layer maintainer objects, I will apply this to my tree.
Later, Juan.
Stefan Hajnoczi
Reviewed-byQuoted 9 lines · Juan Quintela
Quoted 8 lines · Wen Congyang
If we set migration speed in a very large value, block-migration will try to read all data to the memory. Because
(block_mig_state.submitted + block_mig_state.read_done) *BLOCK_SIZE
will be overflow, and it will be always less than rate limit.There is no need to read too many data into memory when the rate limit is very large. So limit the memory usage can fix the overflow problem.
Quoted 7 lines
Quoted 1 line
Signed-off-by Wen Congyang <[email protected]>Reviewed-by Juan Quintela <[email protected]>If no block layer maintainer objects, I will apply this to my tree.
Later, Juan.