Introduce a new taskqueue that runs completely free of Giant, and in

turns runs its tasks free of Giant too.  It is intended that as drivers
become locked down, they will move out of the old, Giant-bound taskqueue
and into this new one.  The old taskqueue has been renamed to
taskqueue_swi_giant, and the new one keeps the name taskqueue_swi.

1 files changed, 19 insertions, 2 deletions

diff --git a/sys/kern/subr_taskqueue.c b/sys/kern/subr_taskqueue.c
index 28fbe38..8cccc8d 100644
--- a/sys/kern/subr_taskqueue.c
+++ b/sys/kern/subr_taskqueue.c
@@ -41,6 +41,7 @@ static MALLOC_DEFINE(M_TASKQUEUE, "taskqueue", "Task Queues");
 static STAILQ_HEAD(taskqueue_list, taskqueue) taskqueue_queues;
 
 static void	*taskqueue_ih;
+static void	*taskqueue_giant_ih;
 static struct mtx taskqueue_queues_mutex;
 
 struct taskqueue {
@@ -219,6 +220,22 @@ taskqueue_swi_run(void *dummy)
 	taskqueue_run(taskqueue_swi);
 }
 
+static void
+taskqueue_swi_giant_enqueue(void *context)
+{
+	swi_sched(taskqueue_giant_ih, 0);
+}
+
+static void
+taskqueue_swi_giant_run(void *dummy)
+{
+	taskqueue_run(taskqueue_swi_giant);
+}
+
 TASKQUEUE_DEFINE(swi, taskqueue_swi_enqueue, 0,
-		 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ, 0,
-		     &taskqueue_ih)); 
+		 swi_add(NULL, "task queue", taskqueue_swi_run, NULL, SWI_TQ,
+		     INTR_MPSAFE, &taskqueue_ih)); 
+
+TASKQUEUE_DEFINE(swi_giant, taskqueue_swi_giant_enqueue, 0,
+		 swi_add(NULL, "Giant task queue", taskqueue_swi_giant_run,
+		     NULL, SWI_TQ_GIANT, 0, &taskqueue_giant_ih));