From: Willy Tarreau <w@1wt.eu>
Date: Mon, 20 Jun 2022 07:14:40 +0000 (+0200)
Subject: MINOR: thread: make wake_thread() take care of the sleeping threads mask
X-Git-Tag: v2.7-dev2~138
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f3efef4d60458fb1d40ac6978169f3e9479f1121;p=thirdparty%2Fhaproxy.git

MINOR: thread: make wake_thread() take care of the sleeping threads mask

Almost every call place of wake_thread() checks for sleeping threads and
clears the sleeping mask itself, while the function is solely used for
there. Let's move the check and the clearing of the bit inside the function
itself. Note that updt_fd_polling() still performs the check because its
rules are a bit different.
---

diff --git a/include/haproxy/fd.h b/include/haproxy/fd.h
index cf2d02b781..010fdacf8e 100644
--- a/include/haproxy/fd.h
+++ b/include/haproxy/fd.h
@@ -369,11 +369,13 @@ static inline unsigned int hap_fd_isset(int fd, unsigned int *evts)
 	return evts[fd / (8*sizeof(*evts))] & (1U << (fd & (8*sizeof(*evts) - 1)));
 }
 
-static inline void wake_thread(int tid)
+static inline void wake_thread(int thr)
 {
-	char c = 'c';
-
-	DISGUISE(write(poller_wr_pipe[tid], &c, 1));
+	if (sleeping_thread_mask & (1UL << thr)) {
+		char c = 'c';
+		_HA_ATOMIC_AND(&sleeping_thread_mask, ~(1UL << thr));
+		DISGUISE(write(poller_wr_pipe[thr], &c, 1));
+	}
 }
 
 
diff --git a/src/fd.c b/src/fd.c
index 079df15af0..96d77bd55f 100644
--- a/src/fd.c
+++ b/src/fd.c
@@ -454,7 +454,6 @@ void updt_fd_polling(const int fd)
 			/* we need to wake up one thread to handle it immediately */
 			int thr = my_ffsl(fdtab[fd].thread_mask & ~tid_bit & all_threads_mask) - 1;
 
-			_HA_ATOMIC_AND(&sleeping_thread_mask, ~(1UL << thr));
 			wake_thread(thr);
 		}
 	}
diff --git a/src/task.c b/src/task.c
index fc698d52bf..76a7432737 100644
--- a/src/task.c
+++ b/src/task.c
@@ -86,10 +86,7 @@ void task_kill(struct task *t)
 			               list_to_mt_list(&((struct tasklet *)t)->list));
 			_HA_ATOMIC_INC(&ha_thread_ctx[thr].rq_total);
 			_HA_ATOMIC_INC(&ha_thread_ctx[thr].tasks_in_list);
-			if (sleeping_thread_mask & (1UL << thr)) {
-				_HA_ATOMIC_AND(&sleeping_thread_mask, ~(1UL << thr));
-				wake_thread(thr);
-			}
+			wake_thread(thr);
 			return;
 		}
 	}
@@ -124,10 +121,7 @@ void tasklet_kill(struct tasklet *t)
 			MT_LIST_APPEND(&ha_thread_ctx[thr].shared_tasklet_list,
 			               list_to_mt_list(&t->list));
 			_HA_ATOMIC_INC(&ha_thread_ctx[thr].rq_total);
-			if (sleeping_thread_mask & (1UL << thr)) {
-				_HA_ATOMIC_AND(&sleeping_thread_mask, ~(1UL << thr));
-				wake_thread(thr);
-			}
+			wake_thread(thr);
 			return;
 		}
 	}
@@ -168,10 +162,7 @@ void __tasklet_wakeup_on(struct tasklet *tl, int thr)
 		/* this tasklet runs on a specific thread. */
 		MT_LIST_APPEND(&ha_thread_ctx[thr].shared_tasklet_list, list_to_mt_list(&tl->list));
 		_HA_ATOMIC_INC(&ha_thread_ctx[thr].rq_total);
-		if (sleeping_thread_mask & (1UL << thr)) {
-			_HA_ATOMIC_AND(&sleeping_thread_mask, ~(1UL << thr));
-			wake_thread(thr);
-		}
+		wake_thread(thr);
 	}
 }
 
@@ -262,12 +253,7 @@ void __task_wakeup(struct task *t)
 		/* If all threads that are supposed to handle this task are sleeping,
 		 * wake one.
 		 */
-		if (sleeping_thread_mask & (1UL << thr)) {
-			unsigned long m = 1UL << thr;
-
-			_HA_ATOMIC_AND(&sleeping_thread_mask, ~m);
-			wake_thread(thr);
-		}
+		wake_thread(thr);
 	}
 #endif
 	return;