diff options
Diffstat (limited to 'migration/ram.c')
| -rw-r--r-- | migration/ram.c | 27 |
1 files changed, 17 insertions, 10 deletions
diff --git a/migration/ram.c b/migration/ram.c index dc1de9ddbc..1338e47665 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -2305,13 +2305,12 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss) } /* - * Do not use multifd for: - * 1. Compression as the first page in the new block should be posted out - * before sending the compressed page - * 2. In postcopy as one whole host page should be placed + * Do not use multifd in postcopy as one whole host page should be + * placed. Meanwhile postcopy requires atomic update of pages, so even + * if host page size == guest page size the dest guest during run may + * still see partially copied pages which is data corruption. */ - if (!save_page_use_compression(rs) && migrate_use_multifd() - && !migration_in_postcopy()) { + if (migrate_use_multifd() && !migration_in_postcopy()) { return ram_save_multifd_page(rs, block, offset); } @@ -2546,14 +2545,22 @@ static int ram_find_and_save_block(RAMState *rs) return pages; } + /* + * Always keep last_seen_block/last_page valid during this procedure, + * because find_dirty_block() relies on these values (e.g., we compare + * last_seen_block with pss.block to see whether we searched all the + * ramblocks) to detect the completion of migration. Having NULL value + * of last_seen_block can conditionally cause below loop to run forever. + */ + if (!rs->last_seen_block) { + rs->last_seen_block = QLIST_FIRST_RCU(&ram_list.blocks); + rs->last_page = 0; + } + pss.block = rs->last_seen_block; pss.page = rs->last_page; pss.complete_round = false; - if (!pss.block) { - pss.block = QLIST_FIRST_RCU(&ram_list.blocks); - } - do { again = true; found = get_queued_page(rs, &pss); |