linux-kernel - [PATCH V7 1/4] softirq: Use sched

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Date:   Tue, 15 Sep 2020 19:56:06 +0800
From:   qianjun.kernel@...il.com
To:     tglx@...utronix.de, peterz@...radead.org, will@...nel.org,
        luto@...nel.org, linux-kernel@...r.kernel.org
Cc:     laoar.shao@...il.com, qais.yousef@....com, urezki@...il.com,
        jun qian <qianjun.kernel@...il.com>
Subject: [PATCH V7 1/4] softirq: Use sched_clock() based timeout

From: jun qian <qianjun.kernel@...il.com>

Replace the jiffies based timeout with a sched_clock() based one.

Signed-off-by: jun qian <qianjun.kernel@...il.com>
---
 kernel/softirq.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index c4201b7f..0db77ab 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -25,6 +25,7 @@
 #include <linux/smpboot.h>
 #include <linux/tick.h>
 #include <linux/irq.h>
+#include <linux/sched/clock.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/irq.h>
@@ -210,7 +211,7 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
  * we want to handle softirqs as soon as possible, but they
  * should not be able to lock up the box.
  */
-#define MAX_SOFTIRQ_TIME  msecs_to_jiffies(2)
+#define MAX_SOFTIRQ_TIME	(2 * NSEC_PER_MSEC)
 #define MAX_SOFTIRQ_RESTART 10
 
 #ifdef CONFIG_TRACE_IRQFLAGS
@@ -248,7 +249,7 @@ static inline void lockdep_softirq_end(bool in_hardirq) { }
 
 asmlinkage __visible void __softirq_entry __do_softirq(void)
 {
-	unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
+	u64 start = sched_clock();
 	unsigned long old_flags = current->flags;
 	int max_restart = MAX_SOFTIRQ_RESTART;
 	struct softirq_action *h;
@@ -307,7 +308,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 
 	pending = local_softirq_pending();
 	if (pending) {
-		if (time_before(jiffies, end) && !need_resched() &&
+		if (sched_clock() - start < MAX_SOFTIRQ_TIME && !need_resched() &&
 		    --max_restart)
 			goto restart;
 
-- 
1.8.3.1