From 018564eaa254c8ffe46cfff065f41798e17e5642 Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Wed, 24 Feb 2021 16:41:11 +0100
Subject: [PATCH] CLEANUP: task: move the tree root detection from
 __task_wakeup() to task_wakeup()

Historically we used to call __task_wakeup() with a known tree root but
this is not the case and the code has remained needlessly complicated
with the root calculation in task_wakeup() passed in argument to
__task_wakeup() which compares it again.

Let's get rid of this and just move the detection code there. This
eliminates some ifdefs and allows to simplify the test conditions quite
a bit.
---
 include/haproxy/task.h | 15 ++-------------
 src/task.c             | 15 +++++++++------
 2 files changed, 11 insertions(+), 19 deletions(-)

diff --git a/include/haproxy/task.h b/include/haproxy/task.h
index 61ac55efa..99171e1c3 100644
--- a/include/haproxy/task.h
+++ b/include/haproxy/task.h
@@ -108,7 +108,7 @@ __decl_thread(extern HA_SPINLOCK_T rq_lock);  /* spin lock related to run queue
 __decl_thread(extern HA_RWLOCK_T wq_lock);    /* RW lock related to the wait queue */
 
 void task_kill(struct task *t);
-void __task_wakeup(struct task *t, struct eb_root *);
+void __task_wakeup(struct task *t);
 void __task_queue(struct task *task, struct eb_root *wq);
 
 struct work_list *work_list_create(int nbthread,
@@ -195,17 +195,6 @@ static inline void _task_wakeup(struct task *t, unsigned int f, const char *file
 {
 	unsigned short state;
 
-#ifdef USE_THREAD
-	struct eb_root *root;
-
-	if (t->thread_mask == tid_bit || global.nbthread == 1)
-		root = &sched->rqueue;
-	else
-		root = &rqueue;
-#else
-	struct eb_root *root = &sched->rqueue;
-#endif
-
 	state = _HA_ATOMIC_OR(&t->state, f);
 	while (!(state & (TASK_RUNNING | TASK_QUEUED))) {
 		if (_HA_ATOMIC_CAS(&t->state, &state, state | TASK_QUEUED)) {
@@ -216,7 +205,7 @@ static inline void _task_wakeup(struct task *t, unsigned int f, const char *file
 			t->debug.caller_file[t->debug.caller_idx] = file;
 			t->debug.caller_line[t->debug.caller_idx] = line;
 #endif
-			__task_wakeup(t, root);
+			__task_wakeup(t);
 			break;
 		}
 	}
diff --git a/src/task.c b/src/task.c
index 028781755..1d1e63c20 100644
--- a/src/task.c
+++ b/src/task.c
@@ -115,14 +115,16 @@ void task_kill(struct task *t)
  * The task must not already be in the run queue. If unsure, use the safer
  * task_wakeup() function.
  */
-void __task_wakeup(struct task *t, struct eb_root *root)
+void __task_wakeup(struct task *t)
 {
-#ifdef USE_THREAD
-	if (root == &rqueue) {
-		HA_SPIN_LOCK(TASK_RQ_LOCK, &rq_lock);
-	}
+	struct eb_root *root = &sched->rqueue;
+
+#ifdef USE_THREAD
+	if (t->thread_mask != tid_bit && global.nbthread != 1) {
+		root = &rqueue;
+
+		HA_SPIN_LOCK(TASK_RQ_LOCK, &rq_lock);
 
-	if (root == &rqueue) {
 		global_tasks_mask |= t->thread_mask;
 		grq_total++;
 		t->rq.key = ++global_rqueue_ticks;
@@ -146,6 +148,7 @@ void __task_wakeup(struct task *t, struct eb_root *root)
 		t->call_date = now_mono_time();
 
 	eb32sc_insert(root, &t->rq, t->thread_mask);
+
 #ifdef USE_THREAD
 	if (root == &rqueue) {
 		_HA_ATOMIC_OR(&t->state, TASK_GLOBAL);