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Date: Mon, 12 Oct 2020 21:50:44 +0800
From: Pingfan Liu <kernelfans@...il.com>
To: linux-kernel@...r.kernel.org
Cc: Pingfan Liu <kernelfans@...il.com>, Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
Thomas Gleixner <tglx@...utronix.de>,
Andy Lutomirski <luto@...nel.org>,
Will Deacon <will@...nel.org>,
"Paul E. McKenney" <paulmck@...nel.org>,
Frederic Weisbecker <frederic@...nel.org>,
Allen Pais <allen.lkml@...il.com>,
Romain Perier <romain.perier@...il.com>
Subject: [PATCH] sched/cputime: correct account of irqtime
__do_softirq() may be interrupted by hardware interrupts. In this case,
irqtime_account_irq() will account the time slice as CPUTIME_SOFTIRQ by
mistake.
By passing irqtime_account_irq() an extra param about either hardirq or
softirq, irqtime_account_irq() can handle the above case.
Signed-off-by: Pingfan Liu <kernelfans@...il.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Juri Lelli <juri.lelli@...hat.com>
Cc: Vincent Guittot <vincent.guittot@...aro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@....com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Ben Segall <bsegall@...gle.com>
Cc: Mel Gorman <mgorman@...e.de>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Will Deacon <will@...nel.org>
Cc: "Paul E. McKenney" <paulmck@...nel.org>
Cc: Frederic Weisbecker <frederic@...nel.org>
Cc: Allen Pais <allen.lkml@...il.com>
Cc: Romain Perier <romain.perier@...il.com>
To: linux-kernel@...r.kernel.org
---
include/linux/hardirq.h | 4 ++--
include/linux/vtime.h | 12 ++++++------
kernel/sched/cputime.c | 4 ++--
kernel/softirq.c | 6 +++---
4 files changed, 13 insertions(+), 13 deletions(-)
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 754f67a..56e7bb5 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -32,7 +32,7 @@ static __always_inline void rcu_irq_enter_check_tick(void)
*/
#define __irq_enter() \
do { \
- account_irq_enter_time(current); \
+ account_irq_enter_time(current, true); \
preempt_count_add(HARDIRQ_OFFSET); \
lockdep_hardirq_enter(); \
} while (0)
@@ -63,7 +63,7 @@ void irq_enter_rcu(void);
#define __irq_exit() \
do { \
lockdep_hardirq_exit(); \
- account_irq_exit_time(current); \
+ account_irq_exit_time(current, true); \
preempt_count_sub(HARDIRQ_OFFSET); \
} while (0)
diff --git a/include/linux/vtime.h b/include/linux/vtime.h
index 2cdeca0..294188ae1 100644
--- a/include/linux/vtime.h
+++ b/include/linux/vtime.h
@@ -98,21 +98,21 @@ static inline void vtime_flush(struct task_struct *tsk) { }
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
-extern void irqtime_account_irq(struct task_struct *tsk);
+extern void irqtime_account_irq(struct task_struct *tsk, bool hardirq);
#else
-static inline void irqtime_account_irq(struct task_struct *tsk) { }
+static inline void irqtime_account_irq(struct task_struct *tsk, bool hardirq) { }
#endif
-static inline void account_irq_enter_time(struct task_struct *tsk)
+static inline void account_irq_enter_time(struct task_struct *tsk, bool hardirq)
{
vtime_account_irq_enter(tsk);
- irqtime_account_irq(tsk);
+ irqtime_account_irq(tsk, hardirq);
}
-static inline void account_irq_exit_time(struct task_struct *tsk)
+static inline void account_irq_exit_time(struct task_struct *tsk, bool hardirq)
{
vtime_account_irq_exit(tsk);
- irqtime_account_irq(tsk);
+ irqtime_account_irq(tsk, hardirq);
}
#endif /* _LINUX_KERNEL_VTIME_H */
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 5a55d23..166f1d7 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -47,7 +47,7 @@ static void irqtime_account_delta(struct irqtime *irqtime, u64 delta,
* Called before incrementing preempt_count on {soft,}irq_enter
* and before decrementing preempt_count on {soft,}irq_exit.
*/
-void irqtime_account_irq(struct task_struct *curr)
+void irqtime_account_irq(struct task_struct *curr, bool hardirq)
{
struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
s64 delta;
@@ -68,7 +68,7 @@ void irqtime_account_irq(struct task_struct *curr)
*/
if (hardirq_count())
irqtime_account_delta(irqtime, delta, CPUTIME_IRQ);
- else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
+ else if (in_serving_softirq() && curr != this_cpu_ksoftirqd() && !hardirq)
irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ);
}
EXPORT_SYMBOL_GPL(irqtime_account_irq);
diff --git a/kernel/softirq.c b/kernel/softirq.c
index bf88d7f6..da59ea39 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -270,7 +270,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
current->flags &= ~PF_MEMALLOC;
pending = local_softirq_pending();
- account_irq_enter_time(current);
+ account_irq_enter_time(current, false);
__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
in_hardirq = lockdep_softirq_start();
@@ -321,7 +321,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
}
lockdep_softirq_end(in_hardirq);
- account_irq_exit_time(current);
+ account_irq_exit_time(current, false);
__local_bh_enable(SOFTIRQ_OFFSET);
WARN_ON_ONCE(in_interrupt());
current_restore_flags(old_flags, PF_MEMALLOC);
@@ -417,7 +417,7 @@ static inline void __irq_exit_rcu(void)
#else
lockdep_assert_irqs_disabled();
#endif
- account_irq_exit_time(current);
+ account_irq_exit_time(current, true);
preempt_count_sub(HARDIRQ_OFFSET);
if (!in_interrupt() && local_softirq_pending())
invoke_softirq();
--
2.7.5
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