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Subject[PATCH 4.12 177/196] sched/cputime: Move the vtime task fields to their own struct
Date
4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Frederic Weisbecker <fweisbec@gmail.com>

commit bac5b6b6b11560f323e71d0ebac4061cfe5f56c0 upstream.

We are about to add vtime accumulation fields to the task struct. Let's
avoid more bloatification and gather vtime information to their own
struct.

Tested-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <kernellwp@gmail.com>
Link: http://lkml.kernel.org/r/1498756511-11714-5-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/init_task.h | 6 +-
include/linux/sched.h | 26 ++++++----
kernel/fork.c | 6 +-
kernel/sched/cputime.c | 114 ++++++++++++++++++++++++++--------------------
4 files changed, 87 insertions(+), 65 deletions(-)

--- 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
--- 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: */
@@ -670,16 +685,7 @@ 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
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1637,9 +1637,9 @@ static __latent_entropy struct task_stru
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)
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -679,17 +679,17 @@ void thread_group_cputime_adjusted(struc
#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_s
* 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_struc
* 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);
-
- write_seqcount_begin(&current->vtime_seqcount);
- current->vtime_state = VTIME_SYS;
- current->vtime_starttime = jiffies;
- write_seqcount_end(&current->vtime_seqcount);
+ struct vtime *vtime = &prev->vtime;
+
+ write_seqcount_begin(&vtime->seqcount);
+ vtime->state = VTIME_INACTIVE;
+ write_seqcount_end(&vtime->seqcount);
+
+ vtime = &current->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,
}

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 */

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