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Date: Wed, 25 Nov 2020 03:15:39 +0100
From: Frederic Weisbecker <frederic@...nel.org>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>,
Frederic Weisbecker <frederic@...nel.org>,
Tony Luck <tony.luck@...el.com>,
Peter Zijlstra <peterz@...radead.org>,
Vasily Gorbik <gor@...ux.ibm.com>,
Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Christian Borntraeger <borntraeger@...ibm.com>,
Fenghua Yu <fenghua.yu@...el.com>,
Heiko Carstens <hca@...ux.ibm.com>
Subject: [RFC PATCH 1/4] sched/vtime: Consolidate IRQ time accounting
The 3 architectures implementing CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
all have their own version of irq time accounting that dispatch the
cputime to the appropriate index: hardirq, softirq, system, idle,
guest... from an all-in-one function.
Instead of having these ad-hoc versions, move the cputime destination
dispatch decision to the core code and leave only the actual per-index
cputime accounting to the architecture.
For now only ia64 and powerpc are handled. s390 will need a slightly
different treatment.
Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Tony Luck <tony.luck@...el.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Heiko Carstens <hca@...ux.ibm.com>
Cc: Vasily Gorbik <gor@...ux.ibm.com>
Cc: Christian Borntraeger <borntraeger@...ibm.com>
---
arch/ia64/kernel/time.c | 22 ++++++++++----
arch/powerpc/kernel/time.c | 60 +++++++++++++++++++++++++++-----------
arch/s390/kernel/vtime.c | 15 ++++++----
include/linux/vtime.h | 8 ++---
kernel/sched/cputime.c | 21 +++++++++++--
5 files changed, 92 insertions(+), 34 deletions(-)
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 7abc5f37bfaf..3fd1daf5bc09 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -138,12 +138,8 @@ void vtime_account_kernel(struct task_struct *tsk)
struct thread_info *ti = task_thread_info(tsk);
__u64 stime = vtime_delta(tsk);
- if ((tsk->flags & PF_VCPU) && !irq_count())
+ if (tsk->flags & PF_VCPU)
ti->gtime += stime;
- else if (hardirq_count())
- ti->hardirq_time += stime;
- else if (in_serving_softirq())
- ti->softirq_time += stime;
else
ti->stime += stime;
}
@@ -156,6 +152,22 @@ void vtime_account_idle(struct task_struct *tsk)
ti->idle_time += vtime_delta(tsk);
}
+void vtime_account_softirq(struct task_struct *tsk)
+{
+ struct thread_info *ti = task_thread_info(tsk);
+
+ ti->softirq_time += vtime_delta(tsk);
+}
+EXPORT_SYMBOL_GPL(vtime_account_softirq);
+
+void vtime_account_hardirq(struct task_struct *tsk)
+{
+ struct thread_info *ti = task_thread_info(tsk);
+
+ ti->hardirq_time += vtime_delta(tsk);
+}
+EXPORT_SYMBOL_GPL(vtime_account_hardirq);
+
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
static irqreturn_t
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 74efe46f5532..6b9496d615b2 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -311,12 +311,11 @@ static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct,
return stime_scaled;
}
-static unsigned long vtime_delta(struct task_struct *tsk,
+static unsigned long vtime_delta(struct cpu_accounting_data *acct,
unsigned long *stime_scaled,
unsigned long *steal_time)
{
unsigned long now, stime;
- struct cpu_accounting_data *acct = get_accounting(tsk);
WARN_ON_ONCE(!irqs_disabled());
@@ -331,29 +330,30 @@ static unsigned long vtime_delta(struct task_struct *tsk,
return stime;
}
-void vtime_account_kernel(struct task_struct *tsk)
+static void vtime_delta_kernel(struct cpu_accounting_data *acct,
+ unsigned long *stime, unsigned long *stime_scaled)
{
- unsigned long stime, stime_scaled, steal_time;
- struct cpu_accounting_data *acct = get_accounting(tsk);
+ unsigned long steal_time;
- stime = vtime_delta(tsk, &stime_scaled, &steal_time);
-
- stime -= min(stime, steal_time);
+ *stime = vtime_delta(acct, stime_scaled, &steal_time);
+ *stime -= min(*stime, steal_time);
acct->steal_time += steal_time;
+}
- if ((tsk->flags & PF_VCPU) && !irq_count()) {
+void vtime_account_kernel(struct task_struct *tsk)
+{
+ struct cpu_accounting_data *acct = get_accounting(tsk);
+ unsigned long stime, stime_scaled;
+
+ vtime_delta_kernel(acct, &stime, &stime_scaled);
+
+ if (tsk->flags & PF_VCPU) {
acct->gtime += stime;
#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
acct->utime_scaled += stime_scaled;
#endif
} else {
- if (hardirq_count())
- acct->hardirq_time += stime;
- else if (in_serving_softirq())
- acct->softirq_time += stime;
- else
- acct->stime += stime;
-
+ acct->stime += stime;
#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
acct->stime_scaled += stime_scaled;
#endif
@@ -366,10 +366,36 @@ void vtime_account_idle(struct task_struct *tsk)
unsigned long stime, stime_scaled, steal_time;
struct cpu_accounting_data *acct = get_accounting(tsk);
- stime = vtime_delta(tsk, &stime_scaled, &steal_time);
+ stime = vtime_delta(acct, &stime_scaled, &steal_time);
acct->idle_time += stime + steal_time;
}
+static void vtime_account_irq(struct cpu_accounting_data *acct,
+ unsigned long *field)
+{
+ unsigned long stime, stime_scaled;
+
+ vtime_delta_kernel(acct, &stime, &stime_scaled);
+ *field += stime;
+#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
+ acct->stime_scaled += stime_scaled;
+#endif
+}
+
+void vtime_account_softirq(struct task_struct *tsk)
+{
+ struct cpu_accounting_data *acct = get_accounting(tsk);
+ vtime_account_irq(acct, &acct->softirq_time);
+}
+EXPORT_SYMBOL_GPL(vtime_account_softirq);
+
+void vtime_account_hardirq(struct task_struct *tsk)
+{
+ struct cpu_accounting_data *acct = get_accounting(tsk);
+ vtime_account_irq(acct, &acct->hardirq_time);
+}
+EXPORT_SYMBOL_GPL(vtime_account_hardirq);
+
static void vtime_flush_scaled(struct task_struct *tsk,
struct cpu_accounting_data *acct)
{
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 8df10d3c8f6c..9fce2ca1b448 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -226,7 +226,7 @@ void vtime_flush(struct task_struct *tsk)
* Update process times based on virtual cpu times stored by entry.S
* to the lowcore fields user_timer, system_timer & steal_clock.
*/
-void vtime_account_irq_enter(struct task_struct *tsk)
+void vtime_account_kernel(struct task_struct *tsk)
{
u64 timer;
@@ -245,12 +245,17 @@ void vtime_account_irq_enter(struct task_struct *tsk)
virt_timer_forward(timer);
}
-EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
-
-void vtime_account_kernel(struct task_struct *tsk)
-__attribute__((alias("vtime_account_irq_enter")));
EXPORT_SYMBOL_GPL(vtime_account_kernel);
+void vtime_account_irq_enter(struct task_struct *tsk)
+__attribute__((alias("vtime_account_kernel")));
+EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
+
+void vtime_account_irq_exit(struct task_struct *tsk)
+__attribute__((alias("vtime_account_kernel")));
+EXPORT_SYMBOL_GPL(vtime_account_irq_exit);
+
+
/*
* Sorted add to a list. List is linear searched until first bigger
* element is found.
diff --git a/include/linux/vtime.h b/include/linux/vtime.h
index 2cdeca062db3..f827b38c3bb7 100644
--- a/include/linux/vtime.h
+++ b/include/linux/vtime.h
@@ -84,11 +84,9 @@ static inline void vtime_init_idle(struct task_struct *tsk, int cpu) { }
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
extern void vtime_account_irq_enter(struct task_struct *tsk);
-static inline void vtime_account_irq_exit(struct task_struct *tsk)
-{
- /* On hard|softirq exit we always account to hard|softirq cputime */
- vtime_account_kernel(tsk);
-}
+extern void vtime_account_irq_exit(struct task_struct *tsk);
+extern void vtime_account_softirq(struct task_struct *tsk);
+extern void vtime_account_hardirq(struct task_struct *tsk);
extern void vtime_flush(struct task_struct *tsk);
#else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
static inline void vtime_account_irq_enter(struct task_struct *tsk) { }
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 5a55d2300452..a042250ecbfe 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -429,12 +429,29 @@ void vtime_task_switch(struct task_struct *prev)
#ifndef __ARCH_HAS_VTIME_ACCOUNT
void vtime_account_irq_enter(struct task_struct *tsk)
{
- if (!in_interrupt() && is_idle_task(tsk))
+ if (hardirq_count()) {
+ vtime_account_hardirq(tsk);
+ } else if (in_serving_softirq()) {
+ vtime_account_softirq(tsk);
+ } else if (is_idle_task(tsk)) {
vtime_account_idle(tsk);
- else
+ } else {
vtime_account_kernel(tsk);
+ }
}
EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
+
+void vtime_account_irq_exit(struct task_struct *tsk)
+{
+ WARN_ON_ONCE(in_task());
+
+ if (hardirq_count()) {
+ vtime_account_hardirq(tsk);
+ } else if (in_serving_softirq()) {
+ vtime_account_softirq(tsk);
+ }
+}
+EXPORT_SYMBOL_GPL(vtime_account_irq_exit);
#endif /* __ARCH_HAS_VTIME_ACCOUNT */
void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
--
2.25.1
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