[PULL 01/10] ram: Add public helper to set colo bitmap

[Juan Quintela]

From: Lukas Straub <lukasstraub2@web.de>

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>
---
 migration/ram.h |  1 +
 migration/ram.c | 17 ++++++++++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/migration/ram.h b/migration/ram.h
index 6fffbeb5f1..ea1f3c25b5 100644
--- 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);
diff --git a/migration/ram.c b/migration/ram.c
index f78e9912cd..b5d03f85ab 100644
--- 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;
 }
-- 
2.40.1