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Cputime cleanups and optimizations:

Browse source 
* Gather vtime headers that were a bit scattered around
 
 * Separate irqtime and vtime namespaces that were
 colliding, resulting in useless calls to irqtime accounting.
 
 * Slightly optimize irq and guest vtime accounting.
 
 Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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Merge tag 'cputime-cleanups-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into sched/core

Pull cputime cleanups and optimizations from Frederic Weisbecker:

 * Gather vtime headers that were a bit scattered around

 * Separate irqtime and vtime namespaces that were
   colliding, resulting in useless calls to irqtime accounting.

 * Slightly optimize irq and guest vtime accounting.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2012-10-30 08:33:01 +01:00
commit 38ca9c927c
10 changed files with 89 additions and 40 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
arch/ia64/kernel/time.c
View file

@ -106,9 +106,9 @@ void vtime_task_switch(struct task_struct *prev)
struct thread_info *ni = task_thread_info(current);
if (idle_task(smp_processor_id()) != prev)
vtime_account_system(prev);
__vtime_account_system(prev);
else
vtime_account_idle(prev);
__vtime_account_idle(prev);
vtime_account_user(prev);
@ -135,14 +135,14 @@ static cputime_t vtime_delta(struct task_struct *tsk)
return delta_stime;
}
void vtime_account_system(struct task_struct *tsk)
void __vtime_account_system(struct task_struct *tsk)
{
cputime_t delta = vtime_delta(tsk);
account_system_time(tsk, 0, delta, delta);
}
void vtime_account_idle(struct task_struct *tsk)
void __vtime_account_idle(struct task_struct *tsk)
{
account_idle_time(vtime_delta(tsk));
}

4
arch/powerpc/kernel/time.c
View file

@ -336,7 +336,7 @@ static u64 vtime_delta(struct task_struct *tsk,
return delta;
}
void vtime_account_system(struct task_struct *tsk)
void __vtime_account_system(struct task_struct *tsk)
{
u64 delta, sys_scaled, stolen;
@ -346,7 +346,7 @@ void vtime_account_system(struct task_struct *tsk)
account_steal_time(stolen);
}
void vtime_account_idle(struct task_struct *tsk)
void __vtime_account_idle(struct task_struct *tsk)
{
u64 delta, sys_scaled, stolen;

4
arch/s390/kernel/vtime.c
View file

@ -140,6 +140,10 @@ void vtime_account(struct task_struct *tsk)
}
EXPORT_SYMBOL_GPL(vtime_account);
void __vtime_account_system(struct task_struct *tsk)
__attribute__((alias("vtime_account")));
EXPORT_SYMBOL_GPL(__vtime_account_system);
void __kprobes vtime_stop_cpu(void)
{
struct s390_idle_data *idle = &__get_cpu_var(s390_idle);

4
arch/s390/kvm/kvm-s390.c
View file

@ -608,9 +608,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
kvm_s390_deliver_pending_interrupts(vcpu);
vcpu->arch.sie_block->icptcode = 0;
local_irq_disable();
kvm_guest_enter();
local_irq_enable();
VCPU_EVENT(vcpu, 6, "entering sie flags %x",
atomic_read(&vcpu->arch.sie_block->cpuflags));
trace_kvm_s390_sie_enter(vcpu,
@ -629,9 +627,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
VCPU_EVENT(vcpu, 6, "exit sie icptcode %d",
vcpu->arch.sie_block->icptcode);
trace_kvm_s390_sie_exit(vcpu, vcpu->arch.sie_block->icptcode);
local_irq_disable();
kvm_guest_exit();
local_irq_enable();
memcpy(&vcpu->run->s.regs.gprs[14], &vcpu->arch.sie_block->gg14, 16);
return rc;

15
include/linux/hardirq.h
View file

@ -4,6 +4,7 @@
#include <linux/preempt.h>
#include <linux/lockdep.h>
#include <linux/ftrace_irq.h>
#include <linux/vtime.h>
#include <asm/hardirq.h>
/*
@ -129,16 +130,6 @@ extern void synchronize_irq(unsigned int irq);
# define synchronize_irq(irq) barrier()
#endif
struct task_struct;
#if !defined(CONFIG_VIRT_CPU_ACCOUNTING) && !defined(CONFIG_IRQ_TIME_ACCOUNTING)
static inline void vtime_account(struct task_struct *tsk)
{
}
#else
extern void vtime_account(struct task_struct *tsk);
#endif
#if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU)
static inline void rcu_nmi_enter(void)
@ -162,7 +153,7 @@ extern void rcu_nmi_exit(void);
*/
#define __irq_enter() \
do { \
vtime_account(current); \
vtime_account_irq_enter(current); \
add_preempt_count(HARDIRQ_OFFSET); \
trace_hardirq_enter(); \
} while (0)
@ -178,7 +169,7 @@ extern void irq_enter(void);
#define __irq_exit() \
do { \
trace_hardirq_exit(); \
vtime_account(current); \
vtime_account_irq_exit(current); \
sub_preempt_count(HARDIRQ_OFFSET); \
} while (0)

9
include/linux/kernel_stat.h
View file

@ -7,6 +7,7 @@
#include <linux/cpumask.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/vtime.h>
#include <asm/irq.h>
#include <asm/cputime.h>
@ -130,12 +131,4 @@ extern void account_process_tick(struct task_struct *, int user);
extern void account_steal_ticks(unsigned long ticks);
extern void account_idle_ticks(unsigned long ticks);
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
extern void vtime_task_switch(struct task_struct *prev);
extern void vtime_account_system(struct task_struct *tsk);
extern void vtime_account_idle(struct task_struct *tsk);
#else
static inline void vtime_task_switch(struct task_struct *prev) { }
#endif
#endif /* _LINUX_KERNEL_STAT_H */

12
include/linux/kvm_host.h
View file

@ -737,7 +737,11 @@ static inline int kvm_deassign_device(struct kvm *kvm,
static inline void kvm_guest_enter(void)
{
BUG_ON(preemptible());
vtime_account(current);
/*
* This is running in ioctl context so we can avoid
* the call to vtime_account() with its unnecessary idle check.
*/
vtime_account_system(current);
current->flags |= PF_VCPU;
/* KVM does not hold any references to rcu protected data when it
* switches CPU into a guest mode. In fact switching to a guest mode
@ -751,7 +755,11 @@ static inline void kvm_guest_enter(void)
static inline void kvm_guest_exit(void)
{
vtime_account(current);
/*
* This is running in ioctl context so we can avoid
* the call to vtime_account() with its unnecessary idle check.
*/
vtime_account_system(current);
current->flags &= ~PF_VCPU;
}

47
include/linux/vtime.h Normal file
View file

@ -0,0 +1,47 @@
#ifndef _LINUX_KERNEL_VTIME_H
#define _LINUX_KERNEL_VTIME_H
struct task_struct;
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
extern void vtime_task_switch(struct task_struct *prev);
extern void __vtime_account_system(struct task_struct *tsk);
extern void vtime_account_system(struct task_struct *tsk);
extern void __vtime_account_idle(struct task_struct *tsk);
extern void vtime_account(struct task_struct *tsk);
#else
static inline void vtime_task_switch(struct task_struct *prev) { }
static inline void __vtime_account_system(struct task_struct *tsk) { }
static inline void vtime_account_system(struct task_struct *tsk) { }
static inline void vtime_account(struct task_struct *tsk) { }
#endif
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
extern void irqtime_account_irq(struct task_struct *tsk);
#else
static inline void irqtime_account_irq(struct task_struct *tsk) { }
#endif
static inline void vtime_account_irq_enter(struct task_struct *tsk)
{
/*
* Hardirq can interrupt idle task anytime. So we need vtime_account()
* that performs the idle check in CONFIG_VIRT_CPU_ACCOUNTING.
* Softirq can also interrupt idle task directly if it calls
* local_bh_enable(). Such case probably don't exist but we never know.
* Ksoftirqd is not concerned because idle time is flushed on context
* switch. Softirqs in the end of hardirqs are also not a problem because
* the idle time is flushed on hardirq time already.
*/
vtime_account(tsk);
irqtime_account_irq(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_system(tsk);
irqtime_account_irq(tsk);
}
#endif /* _LINUX_KERNEL_VTIME_H */

20
kernel/sched/cputime.c
View file

@ -43,7 +43,7 @@ DEFINE_PER_CPU(seqcount_t, irq_time_seq);
* Called before incrementing preempt_count on {soft,}irq_enter
* and before decrementing preempt_count on {soft,}irq_exit.
*/
void vtime_account(struct task_struct *curr)
void irqtime_account_irq(struct task_struct *curr)
{
unsigned long flags;
s64 delta;
@ -73,7 +73,7 @@ void vtime_account(struct task_struct *curr)
irq_time_write_end();
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(vtime_account);
EXPORT_SYMBOL_GPL(irqtime_account_irq);
static int irqtime_account_hi_update(void)
{
@ -433,10 +433,20 @@ void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
*st = cputime.stime;
}
void vtime_account_system(struct task_struct *tsk)
{
unsigned long flags;
local_irq_save(flags);
__vtime_account_system(tsk);
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(vtime_account_system);
/*
* Archs that account the whole time spent in the idle task
* (outside irq) as idle time can rely on this and just implement
* vtime_account_system() and vtime_account_idle(). Archs that
* __vtime_account_system() and __vtime_account_idle(). Archs that
* have other meaning of the idle time (s390 only includes the
* time spent by the CPU when it's in low power mode) must override
* vtime_account().
@ -449,9 +459,9 @@ void vtime_account(struct task_struct *tsk)
local_irq_save(flags);
if (in_interrupt() || !is_idle_task(tsk))
vtime_account_system(tsk);
__vtime_account_system(tsk);
else
vtime_account_idle(tsk);
__vtime_account_idle(tsk);
local_irq_restore(flags);
}

6
kernel/softirq.c
View file

@ -221,7 +221,7 @@ asmlinkage void __do_softirq(void)
current->flags &= ~PF_MEMALLOC;
pending = local_softirq_pending();
vtime_account(current);
vtime_account_irq_enter(current);
__local_bh_disable((unsigned long)__builtin_return_address(0),
SOFTIRQ_OFFSET);
@ -272,7 +272,7 @@ asmlinkage void __do_softirq(void)
lockdep_softirq_exit();
vtime_account(current);
vtime_account_irq_exit(current);
__local_bh_enable(SOFTIRQ_OFFSET);
tsk_restore_flags(current, old_flags, PF_MEMALLOC);
}
@ -341,7 +341,7 @@ static inline void invoke_softirq(void)
*/
void irq_exit(void)
{
vtime_account(current);
vtime_account_irq_exit(current);
trace_hardirq_exit();
sub_preempt_count(IRQ_EXIT_OFFSET);
if (!in_interrupt() && local_softirq_pending())