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Date: Mon, 16 Jan 2012 17:54:18 +0400
From: Konstantin Khlebnikov <khlebnikov@...nvz.org>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...e.hu>,
Marcelo Tosatti <mtosatti@...hat.com>,
Avi Kivity <avi@...hat.com>
Cc: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH] sched: remove task-sched-info dynamic disabler
Currently per-task sched-info statistics can be disabled if delay-accounting is
disabled by boot option. There is no reason for it, sched-info is built-in
into task-struct, and its collecting does not add any extra atomic operations.
In other combinations it either not compiled or cannot be disabled.
This patch removes sched_info_on() and fixes all its users.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@...nvz.org>
---
arch/x86/kvm/cpuid.c | 6 ++----
arch/x86/kvm/x86.c | 4 ----
include/linux/sched.h | 12 ------------
kernel/sched/core.c | 3 +--
kernel/sched/stats.h | 18 +++++-------------
5 files changed, 8 insertions(+), 35 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 89b02bf..12870d8 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -408,10 +408,8 @@ static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
(1 << KVM_FEATURE_NOP_IO_DELAY) |
(1 << KVM_FEATURE_CLOCKSOURCE2) |
(1 << KVM_FEATURE_ASYNC_PF) |
- (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
-
- if (sched_info_on())
- entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
+ (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
+ (1 << KVM_FEATURE_STEAL_TIME);
entry->ebx = 0;
entry->ecx = 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 14d6cad..a60645c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1579,10 +1579,6 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data)
return 1;
break;
case MSR_KVM_STEAL_TIME:
-
- if (unlikely(!sched_info_on()))
- return 1;
-
if (data & KVM_STEAL_RESERVED_MASK)
return 1;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index dd5bf78..eb8842e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -778,18 +778,6 @@ struct task_delay_info {
};
#endif /* CONFIG_TASK_DELAY_ACCT */
-static inline int sched_info_on(void)
-{
-#if IS_ENABLED(CONFIG_SCHEDSTATS) || IS_ENABLED(CONFIG_KVM)
- return 1;
-#elif defined(CONFIG_TASK_DELAY_ACCT)
- extern int delayacct_on;
- return delayacct_on;
-#else
- return 0;
-#endif
-}
-
enum cpu_idle_type {
CPU_IDLE,
CPU_NOT_IDLE,
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0c59dcb..73acf77 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1759,8 +1759,7 @@ void sched_fork(struct task_struct *p)
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
#ifdef CONFIG_TASK_SCHED_INFO
- if (likely(sched_info_on()))
- memset(&p->sched_info, 0, sizeof(p->sched_info));
+ memset(&p->sched_info, 0, sizeof(p->sched_info));
#endif
#if defined(CONFIG_SMP)
p->on_cpu = 0;
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 2322b86..e6363ed 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -63,9 +63,8 @@ static inline void sched_info_dequeued(struct task_struct *t)
{
unsigned long long now = task_rq(t)->clock, delta = 0;
- if (unlikely(sched_info_on()))
- if (t->sched_info.last_queued)
- delta = now - t->sched_info.last_queued;
+ if (t->sched_info.last_queued)
+ delta = now - t->sched_info.last_queued;
sched_info_reset_dequeued(t);
t->sched_info.run_delay += delta;
@@ -98,9 +97,8 @@ static void sched_info_arrive(struct task_struct *t)
*/
static inline void sched_info_queued(struct task_struct *t)
{
- if (unlikely(sched_info_on()))
- if (!t->sched_info.last_queued)
- t->sched_info.last_queued = task_rq(t)->clock;
+ if (!t->sched_info.last_queued)
+ t->sched_info.last_queued = task_rq(t)->clock;
}
/*
@@ -127,7 +125,7 @@ static inline void sched_info_depart(struct task_struct *t)
* the idle task.) We are only called when prev != next.
*/
static inline void
-__sched_info_switch(struct task_struct *prev, struct task_struct *next)
+sched_info_switch(struct task_struct *prev, struct task_struct *next)
{
struct rq *rq = task_rq(prev);
@@ -142,12 +140,6 @@ __sched_info_switch(struct task_struct *prev, struct task_struct *next)
if (next != rq->idle)
sched_info_arrive(next);
}
-static inline void
-sched_info_switch(struct task_struct *prev, struct task_struct *next)
-{
- if (unlikely(sched_info_on()))
- __sched_info_switch(prev, next);
-}
#else
#define sched_info_queued(t) do { } while (0)
#define sched_info_reset_dequeued(t) do { } while (0)
--
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