ram: Add public helper to set colo bitmap

The overhead of the mutex in non-multifd mode is negligible,
because in that case its just the single thread taking the mutex.

This will be used in the next commits to add colo support to multifd.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <22d83cb428f37929563155531bfb69fd8953cc61.1683572883.git.lukasstraub2@web.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>

diff --git a/migration/ram.c b/migration/ram.c
index f78e9912cd5e9572fdfffe0ec04321cd12673108..b5d03f85ab703994ae8b0a5f34164657a683f2e2 100644 (file)
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3408,6 +3408,18 @@ static ram_addr_t host_page_offset_from_ram_block_offset(RAMBlock *block,
     return ((uintptr_t)block->host + offset) & (block->page_size - 1);
 }
 
+void colo_record_bitmap(RAMBlock *block, ram_addr_t *normal, uint32_t pages)
+{
+    qemu_mutex_lock(&ram_state->bitmap_mutex);
+    for (int i = 0; i < pages; i++) {
+        ram_addr_t offset = normal[i];
+        ram_state->migration_dirty_pages += !test_and_set_bit(
+                                                offset >> TARGET_PAGE_BITS,
+                                                block->bmap);
+    }
+    qemu_mutex_unlock(&ram_state->bitmap_mutex);
+}
+
 static inline void *colo_cache_from_block_offset(RAMBlock *block,
                              ram_addr_t offset, bool record_bitmap)
 {
@@ -3425,9 +3437,8 @@ static inline void *colo_cache_from_block_offset(RAMBlock *block,
     * It help us to decide which pages in ram cache should be flushed
     * into VM's RAM later.
     */
-    if (record_bitmap &&
-        !test_and_set_bit(offset >> TARGET_PAGE_BITS, block->bmap)) {
-        ram_state->migration_dirty_pages++;
+    if (record_bitmap) {
+        colo_record_bitmap(block, &offset, 1);
     }
     return block->colo_cache + offset;
 }

diff --git a/migration/ram.h b/migration/ram.h
index 6fffbeb5f1aeb5de7478c564f64ae49a0fb23df5..ea1f3c25b5d7d7b42796937eadecd6cfa888c764 100644 (file)
--- a/migration/ram.h
+++ b/migration/ram.h
@@ -82,6 +82,7 @@ int colo_init_ram_cache(void);
 void colo_flush_ram_cache(void);
 void colo_release_ram_cache(void);
 void colo_incoming_start_dirty_log(void);
+void colo_record_bitmap(RAMBlock *block, ram_addr_t *normal, uint32_t pages);
 
 /* Background snapshot */
 bool ram_write_tracking_available(void);