Starting from pss->page, ram_save_host_page() will check every page and send the dirty pages up to the end of the current host page or the boundary of used_length of the block. If the host page size is a huge page, the step "check" will take a lot of time.
This will improve performance to use migration_bitmap_find_dirty(). Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com> Signed-off-by: Kunkun Jiang <jiangkun...@huawei.com> --- migration/ram.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index c7e18dc2fc..c7a2350198 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1994,6 +1994,8 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss, int tmppages, pages = 0; size_t pagesize_bits = qemu_ram_pagesize(pss->block) >> TARGET_PAGE_BITS; + unsigned long hostpage_boundary = + QEMU_ALIGN_UP(pss->page + 1, pagesize_bits); unsigned long start_page = pss->page; int res; @@ -2005,8 +2007,7 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss, do { /* Check the pages is dirty and if it is send it */ if (!migration_bitmap_clear_dirty(rs, pss->block, pss->page)) { - pss->page++; - continue; + goto find_next; } tmppages = ram_save_target_page(rs, pss, last_stage); @@ -2015,16 +2016,17 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss, } pages += tmppages; - pss->page++; /* Allow rate limiting to happen in the middle of huge pages */ if (pagesize_bits > 1) { migration_rate_limit(); } - } while ((pss->page & (pagesize_bits - 1)) && +find_next: + pss->page = migration_bitmap_find_dirty(rs, pss->block, pss->page); + } while ((pss->page < hostpage_boundary) && offset_in_ramblock(pss->block, ((ram_addr_t)pss->page) << TARGET_PAGE_BITS)); - /* The offset we leave with is the last one we looked at */ - pss->page--; + /* The offset we leave with is the min boundary of host page and block */ + pss->page = MIN(pss->page, hostpage_boundary) - 1; res = ram_save_release_protection(rs, pss, start_page); return (res < 0 ? res : pages); -- 2.23.0