[Qemu-devel] [v4 07/13] migration: Split the function ram_save_page

[Liang Li <liang.z.li@intel.com>]

Split the function ram_save_page for code reuse purpose.

Signed-off-by: Liang Li <liang.z.li@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
---
 arch_init.c | 102 +++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 56 insertions(+), 46 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index 500f299..eae082b 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -595,6 +595,58 @@ static void migration_bitmap_sync_range(ram_addr_t start, ram_addr_t length)
     }
 }
 
+static int save_zero_and_xbzrle_page(QEMUFile *f, uint8_t **current_data,
+                                     RAMBlock *block, ram_addr_t offset,
+                                     bool last_stage, bool *send_async)
+{
+    int bytes_sent = -1;
+    int cont, ret;
+    ram_addr_t current_addr;
+
+    cont = (block == last_sent_block) ? RAM_SAVE_FLAG_CONTINUE : 0;
+
+    /* In doubt sent page as normal */
+    ret = ram_control_save_page(f, block->offset,
+                                offset, TARGET_PAGE_SIZE, &bytes_sent);
+
+    XBZRLE_cache_lock();
+
+    current_addr = block->offset + offset;
+    if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
+        if (ret != RAM_SAVE_CONTROL_DELAYED) {
+            if (bytes_sent > 0) {
+                acct_info.norm_pages++;
+            } else if (bytes_sent == 0) {
+                acct_info.dup_pages++;
+            }
+        }
+    } else if (is_zero_range(*current_data, TARGET_PAGE_SIZE)) {
+        acct_info.dup_pages++;
+        bytes_sent = save_block_hdr(f, block, offset, cont,
+                                    RAM_SAVE_FLAG_COMPRESS);
+        qemu_put_byte(f, 0);
+        bytes_sent++;
+        /* Must let xbzrle know, otherwise a previous (now 0'd) cached
+         * page would be stale
+         */
+        xbzrle_cache_zero_page(current_addr);
+    } else if (!ram_bulk_stage && migrate_use_xbzrle()) {
+        bytes_sent = save_xbzrle_page(f, current_data, current_addr, block,
+                                      offset, cont, last_stage);
+        if (!last_stage) {
+            /* Can't send this cached data async, since the cache page
+             * might get updated before it gets to the wire
+             */
+            if (send_async != NULL) {
+                *send_async = false;
+            }
+        }
+    }
+
+    XBZRLE_cache_unlock();
+
+    return bytes_sent;
+}
 
 /* Needs iothread lock! */
 /* Fix me: there are too many global variables used in migration process. */
@@ -685,60 +737,20 @@ static void migration_bitmap_sync(void)
  *
  * Returns: Number of bytes written.
  */
-static int ram_save_page(QEMUFile *f, RAMBlock* block, ram_addr_t offset,
+static int ram_save_page(QEMUFile *f, RAMBlock *block, ram_addr_t offset,
                          bool last_stage)
 {
     int bytes_sent;
     int cont;
-    ram_addr_t current_addr;
     MemoryRegion *mr = block->mr;
     uint8_t *p;
-    int ret;
     bool send_async = true;
 
-    cont = (block == last_sent_block) ? RAM_SAVE_FLAG_CONTINUE : 0;
-
     p = memory_region_get_ram_ptr(mr) + offset;
-
-    /* In doubt sent page as normal */
-    bytes_sent = -1;
-    ret = ram_control_save_page(f, block->offset,
-                           offset, TARGET_PAGE_SIZE, &bytes_sent);
-
-    XBZRLE_cache_lock();
-
-    current_addr = block->offset + offset;
-    if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
-        if (ret != RAM_SAVE_CONTROL_DELAYED) {
-            if (bytes_sent > 0) {
-                acct_info.norm_pages++;
-            } else if (bytes_sent == 0) {
-                acct_info.dup_pages++;
-            }
-        }
-    } else if (is_zero_range(p, TARGET_PAGE_SIZE)) {
-        acct_info.dup_pages++;
-        bytes_sent = save_block_hdr(f, block, offset, cont,
-                                    RAM_SAVE_FLAG_COMPRESS);
-        qemu_put_byte(f, 0);
-        bytes_sent++;
-        /* Must let xbzrle know, otherwise a previous (now 0'd) cached
-         * page would be stale
-         */
-        xbzrle_cache_zero_page(current_addr);
-    } else if (!ram_bulk_stage && migrate_use_xbzrle()) {
-        bytes_sent = save_xbzrle_page(f, &p, current_addr, block,
-                                      offset, cont, last_stage);
-        if (!last_stage) {
-            /* Can't send this cached data async, since the cache page
-             * might get updated before it gets to the wire
-             */
-            send_async = false;
-        }
-    }
-
-    /* XBZRLE overflow or normal page */
+    bytes_sent = save_zero_and_xbzrle_page(f, &p, block, offset,
+                                           last_stage, &send_async);
     if (bytes_sent == -1) {
+        cont = (block == last_sent_block) ? RAM_SAVE_FLAG_CONTINUE : 0;
         bytes_sent = save_block_hdr(f, block, offset, cont, RAM_SAVE_FLAG_PAGE);
         if (send_async) {
             qemu_put_buffer_async(f, p, TARGET_PAGE_SIZE);
@@ -749,8 +761,6 @@ static int ram_save_page(QEMUFile *f, RAMBlock* block, ram_addr_t offset,
         acct_info.norm_pages++;
     }
 
-    XBZRLE_cache_unlock();
-
     return bytes_sent;
 }
 
-- 
1.9.1