[Tarantool-patches] [PATCH 1/4] [tosquash] move wait_confirm from gc.c to txn_limbo.c

[Serge Petrenko <sergepetrenko@tarantool.org>]

Move all the machinery for waiting for confirmation of the latest limbo
entry from gc.c to txn_limbo.c

Refactor gc_wait_confirm(void) to txn_limbo_wait_confirm(struct txn_limbo *)
and make it return immediately when the limbo is empty to simplify code
a bit.

Refactoring needed for #5097

[TO BE SQUASHED INTO THE PREVIOUS COMMIT]
---
 src/box/gc.c        | 83 ++-------------------------------------------
 src/box/txn_limbo.c | 74 ++++++++++++++++++++++++++++++++++++++++
 src/box/txn_limbo.h |  7 ++++
 3 files changed, 84 insertions(+), 80 deletions(-)

diff --git a/src/box/gc.c b/src/box/gc.c
index 9b7c510f6..170c0a97f 100644
--- a/src/box/gc.c
+++ b/src/box/gc.c
@@ -68,23 +68,6 @@ gc_cleanup_fiber_f(va_list);
 static int
 gc_checkpoint_fiber_f(va_list);
 
-/**
- * Waitpoint stores information about the progress of confirmation.
- * In the case of multimaster support, it will store a bitset
- * or array instead of the boolean.
- */
-struct confirm_waitpoint {
-	/**
-	 * Variable for wake up the fiber that is waiting for
-	 * the end of confirmation.
-	 */
-	struct fiber_cond confirm_cond;
-	/**
-	 * Result flag.
-	 */
-	bool is_confirm;
-};
-
 /**
  * Comparator used for ordering gc_consumer objects
  * lexicographically by their vclock in a binary tree.
@@ -396,64 +379,6 @@ gc_add_checkpoint(const struct vclock *vclock)
 	gc_schedule_cleanup();
 }
 
-static int
-gc_txn_commit_cb(struct trigger *trigger, void *event)
-{
-	(void)event;
-	struct confirm_waitpoint *cwp =
-		(struct confirm_waitpoint *)trigger->data;
-	cwp->is_confirm = true;
-	fiber_cond_signal(&cwp->confirm_cond);
-	return 0;
-}
-
-static int
-gc_txn_rollback_cb(struct trigger *trigger, void *event)
-{
-	(void)event;
-	struct confirm_waitpoint *cwp =
-		(struct confirm_waitpoint *)trigger->data;
-	fiber_cond_signal(&cwp->confirm_cond);
-	return 0;
-}
-
-/**
- * Waiting for confirmation of all "sync" transactions
- * during confirm timeout or fail.
- */
-static int
-gc_wait_confirm(void)
-{
-	/* initialization of a waitpoint. */
-	struct confirm_waitpoint cwp;
-	fiber_cond_create(&cwp.confirm_cond);
-	cwp.is_confirm = false;
-
-	/* Set triggers for the last limbo transaction. */
-	struct trigger on_complete;
-	trigger_create(&on_complete, gc_txn_commit_cb, &cwp, NULL);
-	struct trigger on_rollback;
-	trigger_create(&on_rollback, gc_txn_rollback_cb, &cwp, NULL);
-	struct txn_limbo_entry *tle = txn_limbo_last_entry(&txn_limbo);
-	txn_on_commit(tle->txn, &on_complete);
-	txn_on_rollback(tle->txn, &on_rollback);
-
-	int rc = fiber_cond_wait_timeout(&cwp.confirm_cond,
-					 txn_limbo_confirm_timeout(&txn_limbo));
-	fiber_cond_destroy(&cwp.confirm_cond);
-	if (rc != 0) {
-		/* Clear the triggers if the timeout has been reached. */
-		trigger_clear(&on_complete);
-		trigger_clear(&on_rollback);
-		return -1;
-	}
-	if (!cwp.is_confirm) {
-		/* The transaction has been rollbacked. */
-		return -1;
-	}
-	return 0;
-}
-
 static int
 gc_do_checkpoint(bool is_scheduled)
 {
@@ -478,11 +403,9 @@ gc_do_checkpoint(bool is_scheduled)
 	 * Wait the confirms on all "sync" transactions before
 	 * create a snapshot.
 	 */
-	if (!txn_limbo_is_empty(&txn_limbo)) {
-		rc = gc_wait_confirm();
-		if (rc != 0)
-			goto out;
-	}
+	rc = txn_limbo_wait_confirm(&txn_limbo);
+	if (rc != 0)
+		goto out;
 
 	rc = engine_commit_checkpoint(&checkpoint.vclock);
 	if (rc != 0)
diff --git a/src/box/txn_limbo.c b/src/box/txn_limbo.c
index 18a50d4d3..d3751a28b 100644
--- a/src/box/txn_limbo.c
+++ b/src/box/txn_limbo.c
@@ -339,6 +339,80 @@ txn_limbo_confirm_timeout(struct txn_limbo *limbo)
 	return replication_synchro_timeout;
 }
 
+/**
+ * Waitpoint stores information about the progress of confirmation.
+ * In the case of multimaster support, it will store a bitset
+ * or array instead of the boolean.
+ */
+struct confirm_waitpoint {
+	/**
+	 * Variable for wake up the fiber that is waiting for
+	 * the end of confirmation.
+	 */
+	struct fiber_cond confirm_cond;
+	/**
+	 * Result flag.
+	 */
+	bool is_confirm;
+};
+
+static int
+txn_commit_cb(struct trigger *trigger, void *event)
+{
+	(void)event;
+	struct confirm_waitpoint *cwp =
+		(struct confirm_waitpoint *)trigger->data;
+	cwp->is_confirm = true;
+	fiber_cond_signal(&cwp->confirm_cond);
+	return 0;
+}
+
+static int
+txn_rollback_cb(struct trigger *trigger, void *event)
+{
+	(void)event;
+	struct confirm_waitpoint *cwp =
+		(struct confirm_waitpoint *)trigger->data;
+	fiber_cond_signal(&cwp->confirm_cond);
+	return 0;
+}
+
+int
+txn_limbo_wait_confirm(struct txn_limbo *limbo)
+{
+	if (txn_limbo_is_empty(limbo))
+		return 0;
+
+	/* initialization of a waitpoint. */
+	struct confirm_waitpoint cwp;
+	fiber_cond_create(&cwp.confirm_cond);
+	cwp.is_confirm = false;
+
+	/* Set triggers for the last limbo transaction. */
+	struct trigger on_complete;
+	trigger_create(&on_complete, txn_commit_cb, &cwp, NULL);
+	struct trigger on_rollback;
+	trigger_create(&on_rollback, txn_rollback_cb, &cwp, NULL);
+	struct txn_limbo_entry *tle = txn_limbo_last_entry(limbo);
+	txn_on_commit(tle->txn, &on_complete);
+	txn_on_rollback(tle->txn, &on_rollback);
+
+	int rc = fiber_cond_wait_timeout(&cwp.confirm_cond,
+					 txn_limbo_confirm_timeout(limbo));
+	fiber_cond_destroy(&cwp.confirm_cond);
+	if (rc != 0) {
+		/* Clear the triggers if the timeout has been reached. */
+		trigger_clear(&on_complete);
+		trigger_clear(&on_rollback);
+		return -1;
+	}
+	if (!cwp.is_confirm) {
+		/* The transaction has been rolled back. */
+		return -1;
+	}
+	return 0;
+}
+
 void
 txn_limbo_init(void)
 {
diff --git a/src/box/txn_limbo.h b/src/box/txn_limbo.h
index 987cf9271..138093c7c 100644
--- a/src/box/txn_limbo.h
+++ b/src/box/txn_limbo.h
@@ -198,6 +198,13 @@ txn_limbo_last_entry(struct txn_limbo *limbo)
 double
 txn_limbo_confirm_timeout(struct txn_limbo *limbo);
 
+/**
+ * Waiting for confirmation of all "sync" transactions
+ * during confirm timeout or fail.
+ */
+int
+txn_limbo_wait_confirm(struct txn_limbo *limbo);
+
 void
 txn_limbo_init();
 
-- 
2.24.3 (Apple Git-128)