Add flag to struct task to mark the task as requiring network epoch.

When processing a taskqueue and a task has associated epoch, then
enter for duration of the task.  If consecutive tasks belong to the
same epoch, batch them.  Now we are talking about the network epoch
only.

Shrink the ta_priority size to 8-bits.  No current consumers use
a priority that won't fit into 8 bits.  Also complexity of
taskqueue_enqueue() is a square of maximum value of priority, so
we unlikely ever want to go over UCHAR_MAX here.

Reviewed by:	hselasky
Differential Revision:	https://reviews.freebsd.org/D23518

1 files changed, 15 insertions, 9 deletions

diff --git a/sys/sys/taskqueue.h b/sys/sys/taskqueue.h
index 3f7ff1f529a7..2be3c96bdae4 100644
--- a/sys/sys/taskqueue.h
+++ b/sys/sys/taskqueue.h
@@ -107,8 +107,7 @@ void	taskqueue_set_callback(struct taskqueue *queue,
 	    taskqueue_callback_fn callback, void *context);
 
 #define TASK_INITIALIZER(priority, func, context)	\
-	{ .ta_pending = 0,				\
-	  .ta_priority = (priority),			\
+	{ .ta_priority = (priority),			\
 	  .ta_func = (func),				\
 	  .ta_context = (context) }
 
@@ -121,18 +120,25 @@ void	taskqueue_thread_enqueue(void *context);
 /*
  * Initialise a task structure.
  */
-#define TASK_INIT(task, priority, func, context) do {	\
-	(task)->ta_pending = 0;				\
-	(task)->ta_priority = (priority);		\
-	(task)->ta_func = (func);			\
-	(task)->ta_context = (context);			\
+#define TASK_INIT_FLAGS(task, priority, func, context, flags) do {	\
+	MPASS((priority) >= 0 && (priority) <= 255);		\
+	(task)->ta_pending = 0;					\
+	(task)->ta_priority = (priority);			\
+	(task)->ta_flags = (flags);				\
+	(task)->ta_func = (func);				\
+	(task)->ta_context = (context);				\
 } while (0)
 
+#define TASK_INIT(t, p, f, c)	TASK_INIT_FLAGS(t, p, f, c, 0)
+
 void _timeout_task_init(struct taskqueue *queue,
 	    struct timeout_task *timeout_task, int priority, task_fn_t func,
 	    void *context);
-#define	TIMEOUT_TASK_INIT(queue, timeout_task, priority, func, context) \
-	_timeout_task_init(queue, timeout_task, priority, func, context);
+#define	TIMEOUT_TASK_INIT(queue, timeout_task, priority, func, context)	do { \
+	_Static_assert((priority) >= 0 && (priority) <= 255,	\
+	    "struct task priority is 8 bit in size");           \
+	_timeout_task_init(queue, timeout_task, priority, func, context); \
+} while (0)
 
 /*
  * Declare a reference to a taskqueue.