Merge "sched: avoid migrating when softint on tgt cpu should be short"

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 479e4436f787..39ffd41594ce 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -57,6 +57,13 @@ static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp
 
 DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
 
+/*
+ * active_softirqs -- per cpu, a mask of softirqs that are being handled,
+ * with the expectation that approximate answers are acceptable and therefore
+ * no synchronization.
+ */
+DEFINE_PER_CPU(__u32, active_softirqs);
+
 const char * const softirq_to_name[NR_SOFTIRQS] = {
 	"HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL",
 	"TASKLET", "SCHED", "HRTIMER", "RCU"
@@ -253,6 +260,7 @@ asmlinkage __visible void __do_softirq(void)
 restart:
 	/* Reset the pending bitmask before enabling irqs */
 	set_softirq_pending(0);
+	__this_cpu_write(active_softirqs, pending);
 
 	local_irq_enable();
 
@@ -282,6 +290,7 @@ restart:
 		pending >>= softirq_bit;
 	}
 
+	__this_cpu_write(active_softirqs, 0);
 	rcu_bh_qs();
 	local_irq_disable();