Reproduce the problem:
migrate
migrate_cancel
migrate
Error happen for memory migration
The reason as follows:
1. qemu start, ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION] all set to
1 by a series of cpu_physical_memory_set_dirty_range
2. migration start:ram_init_bitmaps
- memory_global_dirty_log_start: begin log diry
- memory_global_dirty_log_sync: sync dirty bitmap to
ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION]
- migration_bitmap_sync_range: sync ram_list.
dirty_memory[DIRTY_MEMORY_MIGRATION] to RAMBlock.bmap
and ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION] is set to zero
3. migration data...
4. migrate_cancel, will stop log dirty
5. migration start:ram_init_bitmaps
- memory_global_dirty_log_start: begin log diry
- memory_global_dirty_log_sync: sync dirty bitmap to
ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION]
- migration_bitmap_sync_range: sync ram_list.
dirty_memory[DIRTY_MEMORY_MIGRATION] to RAMBlock.bmap
and ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION] is set to zero
Here RAMBlock.bmap only have new logged dirty pages, don't contain
the whole guest pages.
Signed-off-by: Ivan Ren <ivan...@tencent.com>
---
migration/ram.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 908517fc2b..bbebaee0c1 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3173,11 +3173,11 @@ static int ram_state_init(RAMState **rsp)
QSIMPLEQ_INIT(&(*rsp)->src_page_requests);
/*
+ * Count the total number of pages used by ram blocks not including any
+ * gaps due to alignment or unplugs.
* This must match with the initial values of dirty bitmap.
- * Currently we initialize the dirty bitmap to all zeros so
- * here the total dirty page count is zero.
*/
- (*rsp)->migration_dirty_pages = 0;
+ (*rsp)->migration_dirty_pages = ram_bytes_total() >> TARGET_PAGE_BITS;
ram_state_reset(*rsp);
return 0;
@@ -3196,12 +3196,13 @@ static void ram_list_init_bitmaps(void)
* The initial dirty bitmap for migration must be set with all
* ones to make sure we'll migrate every guest RAM page to
* destination.
- * Here we didn't set RAMBlock.bmap simply because it is already
- * set in ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION] in
- * ram_block_add, and that's where we'll sync the dirty bitmaps.
- * Here setting RAMBlock.bmap would be fine too but not necessary.
+ * Here we set RAMBlock.bmap all to 1 because when rebegin a
+ * new migration after a failed migration, ram_list.
+ * dirty_memory[DIRTY_MEMORY_MIGRATION] don't include the whole
+ * guest memory.
*/
block->bmap = bitmap_new(pages);
+ bitmap_set(block->bmap, 0, pages);
if (migrate_postcopy_ram()) {
block->unsentmap = bitmap_new(pages);
bitmap_set(block->unsentmap, 0, pages);
--
2.17.2 (Apple Git-113)
