Use qemu_get_buffer_in_place for xbzrle data

Avoid a data copy (if we're lucky) in the xbzrle code.

Signed-off-by: Dr. David Alan Gilbert <[email protected]>
Reviewed-by: Juan Quintela <[email protected]>
Reviewed-by: Amit Shah <[email protected]>
Message-Id: <1450266458[email protected]>
Signed-off-by: Amit Shah <[email protected]>

diff --git a/migration/ram.c b/migration/ram.c
index 102d1f2b14f101ea03e68ed3c2e9ca71111678fe..994552c57b3c8c6e657cbda5c6e6ffbc7639154e 100644 (file)
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2088,10 +2088,12 @@ static int load_xbzrle(QEMUFile *f, ram_addr_t addr, void *host)
 {
     unsigned int xh_len;
     int xh_flags;
+    uint8_t *loaded_data;
 
     if (!xbzrle_decoded_buf) {
         xbzrle_decoded_buf = g_malloc(TARGET_PAGE_SIZE);
     }
+    loaded_data = xbzrle_decoded_buf;
 
     /* extract RLE header */
     xh_flags = qemu_get_byte(f);
@@ -2107,10 +2109,10 @@ static int load_xbzrle(QEMUFile *f, ram_addr_t addr, void *host)
         return -1;
     }
     /* load data and decode */
-    qemu_get_buffer(f, xbzrle_decoded_buf, xh_len);
+    qemu_get_buffer_in_place(f, &loaded_data, xh_len);
 
     /* decode RLE */
-    if (xbzrle_decode_buffer(xbzrle_decoded_buf, xh_len, host,
+    if (xbzrle_decode_buffer(loaded_data, xh_len, host,
                              TARGET_PAGE_SIZE) == -1) {
         error_report("Failed to load XBZRLE page - decode error!");
         return -1;