[RFC PATCH 3/5] softirq: Defer to workqueue when rescheduling is needed

[Frederic Weisbecker]

One more step toward converting ksoftirqd to per vector workqueues.

Suggested-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Dmitry Safonov <dima@xxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Levin Alexander <alexander.levin@xxxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Radu Rendec <rrendec@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Stanislaw Gruszka <sgruszka@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
---
 kernel/softirq.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 255da68..441e654 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -389,16 +389,14 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 
 	pending = local_softirq_pending() & ~softirq->pending_work_mask;
 	if (pending) {
-		if (need_resched()) {
-			wakeup_softirqd();
-		} else {
-			/* Vectors that overreached the limits are threaded */
-			if (overrun & pending)
-				do_softirq_workqueue(overrun & pending);
-			pending &= ~overrun;
-			if (pending)
-				goto restart;
-		}
+		if (need_resched())
+			overrun = pending;
+		/* Vectors that overreached the limits are threaded */
+		if (overrun & pending)
+			do_softirq_workqueue(overrun & pending);
+		pending &= ~overrun;
+		if (pending)
+			goto restart;
 	}
 
 	lockdep_softirq_end(in_hardirq);
-- 
2.7.4