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authorFrederic Weisbecker <[email protected]>2019-10-16 04:56:48 +0200
committerIngo Molnar <[email protected]>2019-10-29 10:01:10 +0100
commit14faf6fcac4ba33f8fd8d9b2d0278010a9eb1742 (patch)
treee2417f2f0d93bcbd66b5ee6d04fa17e134596a00
parent802f4a827f139f2581b3c50c69d20f8bf4c24af1 (diff)
sched/cputime: Add vtime idle task state
Record idle as a VTIME state instead of guessing it from VTIME_SYS and is_idle_task(). This is going to simplify the cputime read side especially as its state machine is going to further expand in order to fully support kcpustat on nohz_full. Signed-off-by: Frederic Weisbecker <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Jacek Anaszewski <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Pavel Machek <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rafael J . Wysocki <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Viresh Kumar <[email protected]> Cc: Wanpeng Li <[email protected]> Cc: Yauheni Kaliuta <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
-rw-r--r--include/linux/sched.h6
-rw-r--r--kernel/sched/cputime.c13
2 files changed, 12 insertions, 7 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d5d07335a97b..4ae19be2c126 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -249,10 +249,12 @@ struct prev_cputime {
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 is idle */
+ VTIME_IDLE,
/* Task runs in kernelspace in a CPU with VTIME active: */
VTIME_SYS,
+ /* Task runs in userspace in a CPU with VTIME active: */
+ VTIME_USER,
};
struct vtime {
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 40f581692254..2e885e870aa1 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -813,7 +813,7 @@ void vtime_task_switch_generic(struct task_struct *prev)
struct vtime *vtime = &prev->vtime;
write_seqcount_begin(&vtime->seqcount);
- if (is_idle_task(prev))
+ if (vtime->state == VTIME_IDLE)
vtime_account_idle(prev);
else
__vtime_account_kernel(prev, vtime);
@@ -824,7 +824,10 @@ void vtime_task_switch_generic(struct task_struct *prev)
vtime = &current->vtime;
write_seqcount_begin(&vtime->seqcount);
- vtime->state = VTIME_SYS;
+ if (is_idle_task(current))
+ vtime->state = VTIME_IDLE;
+ else
+ vtime->state = VTIME_SYS;
vtime->starttime = sched_clock();
vtime->cpu = smp_processor_id();
write_seqcount_end(&vtime->seqcount);
@@ -837,7 +840,7 @@ void vtime_init_idle(struct task_struct *t, int cpu)
local_irq_save(flags);
write_seqcount_begin(&vtime->seqcount);
- vtime->state = VTIME_SYS;
+ vtime->state = VTIME_IDLE;
vtime->starttime = sched_clock();
vtime->cpu = cpu;
write_seqcount_end(&vtime->seqcount);
@@ -888,8 +891,8 @@ void task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
*utime = t->utime;
*stime = t->stime;
- /* Task is sleeping, nothing to add */
- if (vtime->state == VTIME_INACTIVE || is_idle_task(t))
+ /* Task is sleeping or idle, nothing to add */
+ if (vtime->state < VTIME_SYS)
continue;
delta = vtime_delta(vtime);