1. Add a dedicated handler for MigrationOps::ram_save_target_page in multifd live migration. 2. Refactor ram_save_target_page_legacy so that the legacy and multifd handlers don't have internal functions calling into each other.
Signed-off-by: Hao Xiang <hao.xi...@bytedance.com> --- migration/ram.c | 43 ++++++++++++++++++++++++++++++------------- 1 file changed, 30 insertions(+), 13 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 414cd0d753..f60627e11a 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1123,10 +1123,6 @@ static int save_zero_page(RAMState *rs, PageSearchStatus *pss, QEMUFile *file = pss->pss_channel; int len = 0; - if (migrate_zero_page_detection() == ZERO_PAGE_DETECTION_NONE) { - return 0; - } - if (!buffer_is_zero(p, TARGET_PAGE_SIZE)) { return 0; } @@ -2046,7 +2042,6 @@ static bool save_compress_page(RAMState *rs, PageSearchStatus *pss, */ static int ram_save_target_page_legacy(RAMState *rs, PageSearchStatus *pss) { - RAMBlock *block = pss->block; ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS; int res; @@ -2062,17 +2057,34 @@ static int ram_save_target_page_legacy(RAMState *rs, PageSearchStatus *pss) return 1; } + return ram_save_page(rs, pss); +} + +/** + * ram_save_target_page_multifd: send one target page to multifd workers + * + * Returns 1 if the page was queued, -1 otherwise. + * + * @rs: current RAM state + * @pss: data about the page we want to send + */ +static int ram_save_target_page_multifd(RAMState *rs, PageSearchStatus *pss) +{ + RAMBlock *block = pss->block; + ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS; + /* - * 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. + * Backward compatibility support. While using multifd live + * migration, we still need to handle zero page checking on the + * migration main thread. */ - if (migrate_multifd() && !migration_in_postcopy()) { - return ram_save_multifd_page(block, offset); + if (migrate_zero_page_detection() == ZERO_PAGE_DETECTION_LEGACY) { + if (save_zero_page(rs, pss, offset)) { + return 1; + } } - return ram_save_page(rs, pss); + return ram_save_multifd_page(block, offset); } /* Should be called before sending a host page */ @@ -2984,7 +2996,12 @@ static int ram_save_setup(QEMUFile *f, void *opaque) } migration_ops = g_malloc0(sizeof(MigrationOps)); - migration_ops->ram_save_target_page = ram_save_target_page_legacy; + + if (migrate_multifd()) { + migration_ops->ram_save_target_page = ram_save_target_page_multifd; + } else { + migration_ops->ram_save_target_page = ram_save_target_page_legacy; + } bql_unlock(); ret = multifd_send_sync_main(); -- 2.30.2