From: Witold Kręcicki <wpk@isc.org>
Date: Thu, 25 Oct 2018 06:31:53 +0000 (+0000)
Subject: Document isc_task_sendto properly, make sure that cpu we're sending to is always... 
X-Git-Tag: v9.13.4~51^2~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f166cabcae9c11d34bf269dd45435a6c13df6900;p=thirdparty%2Fbind9.git

Document isc_task_sendto properly, make sure that cpu we're sending to is always sane
---

diff --git a/lib/isc/include/isc/task.h b/lib/isc/include/isc/task.h
index d3146f51a78..4ee783aedc0 100644
--- a/lib/isc/include/isc/task.h
+++ b/lib/isc/include/isc/task.h
@@ -212,7 +212,8 @@ isc_task_send(isc_task_t *task, isc_event_t **eventp);
 void
 isc_task_sendto(isc_task_t *task, isc_event_t **eventp, int c);
 /*%<
- * Send '*event' to 'task'.
+ * Send '*event' to 'task', if task is idle try starting it on cpu 'c'
+ * If 'c' is smaller than 0 then cpu is selected randomly.
  *
  * Requires:
  *
@@ -231,7 +232,8 @@ void
 isc_task_sendanddetach(isc_task_t **taskp, isc_event_t **eventp);
 /*%<
  * Send '*event' to '*taskp' and then detach '*taskp' from its
- * task.
+ * task. If task is idle try starting it on cpu 'c'
+ * If 'c' is smaller than 0 then cpu is selected randomly.
  *
  * Requires:
  *
diff --git a/lib/isc/task.c b/lib/isc/task.c
index 55418590bf3..e2124dd53c8 100644
--- a/lib/isc/task.c
+++ b/lib/isc/task.c
@@ -481,14 +481,13 @@ isc_task_sendto(isc_task_t *task0, isc_event_t **eventp, int c) {
 	 */
 
 	REQUIRE(VALID_TASK(task));
+	XTRACE("isc_task_send");
 
-	if (c == -1) {
+	if (c < 0) {
 		c = atomic_fetch_add_explicit(&task->manager->curq, 1,
-					      memory_order_relaxed)
-					      % task->manager->workers;
+					      memory_order_relaxed);
 	}
-
-	XTRACE("isc_task_send");
+	c %= task->manager->workers;
 
 	/*
 	 * We're trying hard to hold locks for as short a time as possible.
@@ -532,13 +531,14 @@ isc_task_sendtoanddetach(isc_task_t **taskp, isc_event_t **eventp, int c) {
 	REQUIRE(taskp != NULL);
 	task = (isc__task_t *)*taskp;
 	REQUIRE(VALID_TASK(task));
-	if (c == -1) {
+	XTRACE("isc_task_sendanddetach");
+
+	if (c < 0) {
 		c = atomic_fetch_add_explicit(&task->manager->curq, 1,
-					      memory_order_relaxed)
-					      % task->manager->workers;
+					      memory_order_relaxed);
 	}
+	c %= task->manager->workers;
 
-	XTRACE("isc_task_sendanddetach");
 	LOCK(&task->lock);
 	idle1 = task_send(task, eventp, c);
 	idle2 = task_detach(task);