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Date: Thu, 29 Jun 2017 19:15:10 +0200
From: Frederic Weisbecker <fweisbec@...il.com>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>,
Luiz Capitulino <lcapitulino@...hat.com>,
Ingo Molnar <mingo@...nel.org>,
Wanpeng Li <kernellwp@...il.com>,
Rik van Riel <riel@...hat.com>
Subject: [PATCH 4/5] sched: Move vtime task fields to their own struct
We are about to add vtime accumulation fields to the task struct. Let's
avoid more bloatification and gather vtime informations to their own
struct.
Cc: Wanpeng Li <kernellwp@...il.com>
Cc: Rik van Riel <riel@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Luiz Capitulino <lcapitulino@...hat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
---
include/linux/init_task.h | 6 +--
include/linux/sched.h | 26 ++++++-----
kernel/fork.c | 6 +--
kernel/sched/cputime.c | 112 ++++++++++++++++++++++++++--------------------
4 files changed, 86 insertions(+), 64 deletions(-)
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 3d53733..a2f6707 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -170,9 +170,9 @@ extern struct cred init_cred;
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
# define INIT_VTIME(tsk) \
- .vtime_seqcount = SEQCNT_ZERO(tsk.vtime_seqcount), \
- .vtime_starttime = 0, \
- .vtime_state = VTIME_SYS,
+ .vtime.seqcount = SEQCNT_ZERO(tsk.vtime.seqcount), \
+ .vtime.starttime = 0, \
+ .vtime.state = VTIME_SYS,
#else
# define INIT_VTIME(tsk)
#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 22d2d9b..4a48c3f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -223,6 +223,21 @@ struct task_cputime {
#define prof_exp stime
#define sched_exp sum_exec_runtime
+enum vtime_state {
+ /* Task is sleeping or running in a CPU with VTIME inactive: */
+ VTIME_INACTIVE = 0,
+ /* Task runs in userspace in a CPU with VTIME active: */
+ VTIME_USER,
+ /* Task runs in kernelspace in a CPU with VTIME active: */
+ VTIME_SYS,
+};
+
+struct vtime {
+ seqcount_t seqcount;
+ unsigned long long starttime;
+ enum vtime_state state;
+};
+
struct sched_info {
#ifdef CONFIG_SCHED_INFO
/* Cumulative counters: */
@@ -688,16 +703,7 @@ struct task_struct {
u64 gtime;
struct prev_cputime prev_cputime;
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
- seqcount_t vtime_seqcount;
- unsigned long long vtime_starttime;
- enum {
- /* Task is sleeping or running in a CPU with VTIME inactive: */
- VTIME_INACTIVE = 0,
- /* Task runs in userspace in a CPU with VTIME active: */
- VTIME_USER,
- /* Task runs in kernelspace in a CPU with VTIME active: */
- VTIME_SYS,
- } vtime_state;
+ struct vtime vtime;
#endif
#ifdef CONFIG_NO_HZ_FULL
diff --git a/kernel/fork.c b/kernel/fork.c
index 83c4f9b..d927ec1 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1637,9 +1637,9 @@ static __latent_entropy struct task_struct *copy_process(
prev_cputime_init(&p->prev_cputime);
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
- seqcount_init(&p->vtime_seqcount);
- p->vtime_starttime = 0;
- p->vtime_state = VTIME_INACTIVE;
+ seqcount_init(&p->vtime.seqcount);
+ p->vtime.starttime = 0;
+ p->vtime.state = VTIME_INACTIVE;
#endif
#if defined(SPLIT_RSS_COUNTING)
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 6b152c2..b28d312 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -679,17 +679,17 @@ void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
#endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
-static u64 vtime_delta(struct task_struct *tsk)
+static u64 vtime_delta(struct vtime *vtime)
{
unsigned long now = READ_ONCE(jiffies);
- if (time_before(now, (unsigned long)tsk->vtime_starttime))
+ if (time_before(now, (unsigned long)vtime->starttime))
return 0;
- return jiffies_to_nsecs(now - tsk->vtime_starttime);
+ return jiffies_to_nsecs(now - vtime->starttime);
}
-static u64 get_vtime_delta(struct task_struct *tsk)
+static u64 get_vtime_delta(struct vtime *vtime)
{
unsigned long now = READ_ONCE(jiffies);
u64 delta, other;
@@ -701,49 +701,56 @@ static u64 get_vtime_delta(struct task_struct *tsk)
* elapsed time. Limit account_other_time to prevent rounding
* errors from causing elapsed vtime to go negative.
*/
- delta = jiffies_to_nsecs(now - tsk->vtime_starttime);
+ delta = jiffies_to_nsecs(now - vtime->starttime);
other = account_other_time(delta);
- WARN_ON_ONCE(tsk->vtime_state == VTIME_INACTIVE);
- tsk->vtime_starttime = now;
+ WARN_ON_ONCE(vtime->state == VTIME_INACTIVE);
+ vtime->starttime = now;
return delta - other;
}
static void __vtime_account_system(struct task_struct *tsk)
{
- account_system_time(tsk, irq_count(), get_vtime_delta(tsk));
+ account_system_time(tsk, irq_count(), get_vtime_delta(&tsk->vtime));
}
void vtime_account_system(struct task_struct *tsk)
{
- if (!vtime_delta(tsk))
+ struct vtime *vtime = &tsk->vtime;
+
+ if (!vtime_delta(vtime))
return;
- write_seqcount_begin(&tsk->vtime_seqcount);
+ write_seqcount_begin(&vtime->seqcount);
__vtime_account_system(tsk);
- write_seqcount_end(&tsk->vtime_seqcount);
+ write_seqcount_end(&vtime->seqcount);
}
void vtime_user_enter(struct task_struct *tsk)
{
- write_seqcount_begin(&tsk->vtime_seqcount);
- if (vtime_delta(tsk))
+ struct vtime *vtime = &tsk->vtime;
+
+ write_seqcount_begin(&vtime->seqcount);
+ if (vtime_delta(vtime))
__vtime_account_system(tsk);
- tsk->vtime_snap_whence = VTIME_USER;
- write_seqcount_end(&tsk->vtime_seqcount);
+ vtime->state = VTIME_USER;
+ write_seqcount_end(&vtime->seqcount);
}
void vtime_user_exit(struct task_struct *tsk)
{
- write_seqcount_begin(&tsk->vtime_seqcount);
- if (vtime_delta(tsk))
- account_user_time(tsk, get_vtime_delta(tsk));
- tsk->vtime_snap_whence = VTIME_SYS;
- write_seqcount_end(&tsk->vtime_seqcount);
+ struct vtime *vtime = &tsk->vtime;
+
+ write_seqcount_begin(&vtime->seqcount);
+ if (vtime_delta(vtime))
+ account_user_time(tsk, get_vtime_delta(vtime));
+ vtime->state = VTIME_SYS;
+ write_seqcount_end(&vtime->seqcount);
}
void vtime_guest_enter(struct task_struct *tsk)
{
+ struct vtime *vtime = &tsk->vtime;
/*
* The flags must be updated under the lock with
* the vtime_starttime flush and update.
@@ -751,54 +758,62 @@ void vtime_guest_enter(struct task_struct *tsk)
* synchronization against the reader (task_gtime())
* that can thus safely catch up with a tickless delta.
*/
- write_seqcount_begin(&tsk->vtime_seqcount);
- if (vtime_delta(tsk))
+ write_seqcount_begin(&vtime->seqcount);
+ if (vtime_delta(vtime))
__vtime_account_system(tsk);
current->flags |= PF_VCPU;
- write_seqcount_end(&tsk->vtime_seqcount);
+ write_seqcount_end(&vtime->seqcount);
}
EXPORT_SYMBOL_GPL(vtime_guest_enter);
void vtime_guest_exit(struct task_struct *tsk)
{
- write_seqcount_begin(&tsk->vtime_seqcount);
+ struct vtime *vtime = &tsk->vtime;
+
+ write_seqcount_begin(&vtime->seqcount);
__vtime_account_system(tsk);
current->flags &= ~PF_VCPU;
- write_seqcount_end(&tsk->vtime_seqcount);
+ write_seqcount_end(&vtime->seqcount);
}
EXPORT_SYMBOL_GPL(vtime_guest_exit);
void vtime_account_idle(struct task_struct *tsk)
{
- account_idle_time(get_vtime_delta(tsk));
+ account_idle_time(get_vtime_delta(&tsk->vtime));
}
void arch_vtime_task_switch(struct task_struct *prev)
{
- write_seqcount_begin(&prev->vtime_seqcount);
- prev->vtime_state = VTIME_INACTIVE;
- write_seqcount_end(&prev->vtime_seqcount);
+ struct vtime *vtime = &prev->vtime;
- write_seqcount_begin(¤t->vtime_seqcount);
- current->vtime_state = VTIME_SYS;
- current->vtime_starttime = jiffies;
- write_seqcount_end(¤t->vtime_seqcount);
+ write_seqcount_begin(&vtime->seqcount);
+ vtime->state = VTIME_INACTIVE;
+ write_seqcount_end(&vtime->seqcount);
+
+ vtime = ¤t->vtime;
+
+ write_seqcount_begin(&vtime->seqcount);
+ vtime->state = VTIME_SYS;
+ vtime->starttime = jiffies;
+ write_seqcount_end(&vtime->seqcount);
}
void vtime_init_idle(struct task_struct *t, int cpu)
{
+ struct vtime *vtime = &t->vtime;
unsigned long flags;
local_irq_save(flags);
- write_seqcount_begin(&t->vtime_seqcount);
- t->vtime_state = VTIME_SYS;
- t->vtime_starttime = jiffies;
- write_seqcount_end(&t->vtime_seqcount);
+ write_seqcount_begin(&vtime->seqcount);
+ vtime->state = VTIME_SYS;
+ vtime->starttime = jiffies;
+ write_seqcount_end(&vtime->seqcount);
local_irq_restore(flags);
}
u64 task_gtime(struct task_struct *t)
{
+ struct vtime *vtime = &t->vtime;
unsigned int seq;
u64 gtime;
@@ -806,13 +821,13 @@ u64 task_gtime(struct task_struct *t)
return t->gtime;
do {
- seq = read_seqcount_begin(&t->vtime_seqcount);
+ seq = read_seqcount_begin(&vtime->seqcount);
gtime = t->gtime;
- if (t->vtime_state == VTIME_SYS && t->flags & PF_VCPU)
- gtime += vtime_delta(t);
+ if (vtime->state == VTIME_SYS && t->flags & PF_VCPU)
+ gtime += vtime_delta(vtime);
- } while (read_seqcount_retry(&t->vtime_seqcount, seq));
+ } while (read_seqcount_retry(&vtime->seqcount, seq));
return gtime;
}
@@ -824,8 +839,9 @@ u64 task_gtime(struct task_struct *t)
*/
void task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
{
- u64 delta;
+ struct vtime *vtime = &t->vtime;
unsigned int seq;
+ u64 delta;
if (!vtime_accounting_enabled()) {
*utime = t->utime;
@@ -834,25 +850,25 @@ void task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
}
do {
- seq = read_seqcount_begin(&t->vtime_seqcount);
+ seq = read_seqcount_begin(&vtime->seqcount);
*utime = t->utime;
*stime = t->stime;
/* Task is sleeping, nothing to add */
- if (t->vtime_state == VTIME_INACTIVE || is_idle_task(t))
+ if (vtime->state == VTIME_INACTIVE || is_idle_task(t))
continue;
- delta = vtime_delta(t);
+ delta = vtime_delta(vtime);
/*
* Task runs either in user or kernel space, add pending nohz time to
* the right place.
*/
- if (t->vtime_state == VTIME_USER || t->flags & PF_VCPU)
+ if (vtime->state == VTIME_USER || t->flags & PF_VCPU)
*utime += delta;
- else if (t->vtime_state == VTIME_SYS)
+ else if (vtime->state == VTIME_SYS)
*stime += delta;
- } while (read_seqcount_retry(&t->vtime_seqcount, seq));
+ } while (read_seqcount_retry(&vtime->seqcount, seq));
}
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
--
2.7.4
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