netdev - [PATCH 2/9] softirq: Use sched

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Date: Fri, 5 May 2023 19:33:08 +0800
From: Liu Jian <liujian56@...wei.com>
To: <corbet@....net>, <paulmck@...nel.org>, <frederic@...nel.org>,
	<quic_neeraju@...cinc.com>, <joel@...lfernandes.org>,
	<josh@...htriplett.org>, <boqun.feng@...il.com>, <rostedt@...dmis.org>,
	<mathieu.desnoyers@...icios.com>, <jiangshanlai@...il.com>,
	<qiang1.zhang@...el.com>, <jstultz@...gle.com>, <tglx@...utronix.de>,
	<sboyd@...nel.org>, <davem@...emloft.net>, <edumazet@...gle.com>,
	<kuba@...nel.org>, <pabeni@...hat.com>, <peterz@...radead.org>,
	<frankwoo@...gle.com>, <Rhinewuwu@...gle.com>
CC: <liujian56@...wei.com>, <linux-doc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <rcu@...r.kernel.org>,
	<netdev@...r.kernel.org>
Subject: [PATCH 2/9] softirq: Use sched_clock() based timeout

From: Peter Zijlstra <peterz@...radead.org>

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

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Liu Jian <liujian56@...wei.com>
---
 kernel/softirq.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index bff5debf6ce6..59f16a9af5d1 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -27,6 +27,7 @@
 #include <linux/tick.h>
 #include <linux/irq.h>
 #include <linux/wait_bit.h>
+#include <linux/sched/clock.h>
 
 #include <asm/softirq_stack.h>
 
@@ -489,7 +490,7 @@ asmlinkage __visible void do_softirq(void)
  * 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
@@ -527,9 +528,9 @@ static inline void lockdep_softirq_end(bool in_hardirq) { }
 
 asmlinkage __visible void __softirq_entry __do_softirq(void)
 {
-	unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
 	unsigned long old_flags = current->flags;
 	int max_restart = MAX_SOFTIRQ_RESTART;
+	u64 start = sched_clock();
 	struct softirq_action *h;
 	unsigned long pending;
 	unsigned int vec_nr;
@@ -584,7 +585,7 @@ 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;
 
-- 
2.34.1