From 2e36bc1b884a6fc6bc626b13db4960773ad976f7 Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Thu, 7 Nov 2019 20:39:02 +0800 Subject: [PATCH] migration/postcopy: reduce memset when it is zero page and matches_target_page_size In this case, page_buffer content would not be used. Skip this to save some time. Signed-off-by: Wei Yang Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- migration/ram.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/migration/ram.c b/migration/ram.c index 5cd066467c..bdb0316892 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -4126,7 +4126,13 @@ static int ram_load_postcopy(QEMUFile *f) switch (flags & ~RAM_SAVE_FLAG_CONTINUE) { case RAM_SAVE_FLAG_ZERO: ch = qemu_get_byte(f); - memset(page_buffer, ch, TARGET_PAGE_SIZE); + /* + * Can skip to set page_buffer when + * this is a zero page and (block->page_size == TARGET_PAGE_SIZE). + */ + if (ch || !matches_target_page_size) { + memset(page_buffer, ch, TARGET_PAGE_SIZE); + } if (ch) { all_zero = false; }