[Qemu-devel] [PATCH 21/41] migration: run setup callbacks out of big lock

[Paolo Bonzini]

Only the migration_bitmap_sync() call needs the iothread lock.

Signed-off-by: Paolo Bonzini <address@hidden>
---
 arch_init.c                 |   10 ++++++----
 block-migration.c           |    2 ++
 include/migration/vmstate.h |    2 +-
 migration.c                 |    2 --
 savevm.c                    |    3 +++
 5 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index adca555..6f0e389 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -569,10 +569,6 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
     bitmap_set(migration_bitmap, 0, ram_pages);
     migration_dirty_pages = ram_pages;
 
-    qemu_mutex_lock_ramlist();
-    bytes_transferred = 0;
-    reset_ram_globals();
-
     if (migrate_use_xbzrle()) {
         XBZRLE.cache = cache_init(migrate_xbzrle_cache_size() /
                                   TARGET_PAGE_SIZE,
@@ -586,8 +582,14 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
         acct_clear();
     }
 
+    qemu_mutex_lock_iothread();
+    qemu_mutex_lock_ramlist();
+    bytes_transferred = 0;
+    reset_ram_globals();
+
     memory_global_dirty_log_start();
     migration_bitmap_sync();
+    qemu_mutex_unlock_iothread();
 
     qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
 
diff --git a/block-migration.c b/block-migration.c
index 143180c..d673658 100644
--- a/block-migration.c
+++ b/block-migration.c
@@ -583,10 +583,12 @@ static int block_save_setup(QEMUFile *f, void *opaque)
     DPRINTF("Enter save live setup submitted %d transferred %d\n",
             block_mig_state.submitted, block_mig_state.transferred);
 
+    qemu_mutex_lock_iothread();
     init_blk_migration(f);
 
     /* start track dirty blocks */
     set_dirty_tracking(1);
+    qemu_mutex_unlock_iothread();
 
     ret = flush_blks(f);
     blk_mig_reset_dirty_cursor();
diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
index 5f803f5..abc3b47 100644
--- a/include/migration/vmstate.h
+++ b/include/migration/vmstate.h
@@ -34,7 +34,6 @@ typedef struct SaveVMHandlers {
     void (*set_params)(const MigrationParams *params, void * opaque);
     SaveStateHandler *save_state;
 
-    int (*save_live_setup)(QEMUFile *f, void *opaque);
     void (*cancel)(void *opaque);
     int (*save_live_complete)(QEMUFile *f, void *opaque);
 
@@ -49,6 +48,7 @@ typedef struct SaveVMHandlers {
     int (*save_live_iterate)(QEMUFile *f, void *opaque);
 
     /* This runs outside the iothread lock!  */
+    int (*save_live_setup)(QEMUFile *f, void *opaque);
     uint64_t (*save_live_pending)(QEMUFile *f, void *opaque, uint64_t 
max_size);
 
     LoadStateHandler *load_state;
diff --git a/migration.c b/migration.c
index cb7f7b4..d6a7dff 100644
--- a/migration.c
+++ b/migration.c
@@ -648,10 +648,8 @@ static void *buffered_file_thread(void *opaque)
     bool old_vm_running = false;
     bool last_round = false;
 
-    qemu_mutex_lock_iothread();
     DPRINTF("beginning savevm\n");
     qemu_savevm_state_begin(s->file, &s->params);
-    qemu_mutex_unlock_iothread();
 
     while (s->state == MIG_STATE_ACTIVE) {
         int64_t current_time = qemu_get_clock_ms(rt_clock);
diff --git a/savevm.c b/savevm.c
index e10a045..7c7774e 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1768,7 +1768,10 @@ static int qemu_savevm_state(QEMUFile *f)
         return -EINVAL;
     }
 
+    qemu_mutex_unlock_iothread();
     qemu_savevm_state_begin(f, &params);
+    qemu_mutex_lock_iothread();
+
     while (qemu_file_get_error(f) == 0) {
         if (qemu_savevm_state_iterate(f) > 0) {
             break;
-- 
1.7.1