diff mbox series

[PULL,16/30] migration/postcopy: reduce memset when it is zero page and matches_target_page_size

Message ID 20200114125254.4515-17-quintela@redhat.com
State New
Headers show
Series [PULL,01/30] multifd: Initialize local variable | expand

Commit Message

Juan Quintela Jan. 14, 2020, 12:52 p.m. UTC 
From: Wei Yang <richardw.yang@linux.intel.com>

In this case, page_buffer content would not be used.

Skip this to save some time.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/migration/ram.c b/migration/ram.c
index 0c6992db9a..885cd31191 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;
             }