diff mbox

[PULL,2/2] block-migration: limit the memory usage

Message ID 1448461926-31401-3-git-send-email-quintela@redhat.com
State New
Headers show

Commit Message

Juan Quintela Nov. 25, 2015, 2:32 p.m. UTC 
From: Wen Congyang <wency@cn.fujitsu.com>

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 <wency@cn.fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/block.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
diff mbox

Patch

diff --git a/migration/block.c b/migration/block.c
index 310e2b3..656f38f 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -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 */