The following commit has been merged into the sched/core branch of tip: Commit-ID: 14faf6fcac4ba33f8fd8d9b2d0278010a9eb1742 Gitweb: https://git.kernel.org/tip/14faf6fcac4ba33f8fd8d9b2d0278010a9eb1742 Author: Frederic Weisbecker <frederic@xxxxxxxxxx> AuthorDate: Wed, 16 Oct 2019 04:56:48 +02:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Tue, 29 Oct 2019 10:01:10 +01:00 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 <frederic@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Pavel Machek <pavel@xxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Rafael J . Wysocki <rjw@xxxxxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Viresh Kumar <viresh.kumar@xxxxxxxxxx> Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx> Cc: Yauheni Kaliuta <yauheni.kaliuta@xxxxxxxxxx> Link: https://lkml.kernel.org/r/20191016025700.31277-3-frederic@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- include/linux/sched.h | 6 ++++-- kernel/sched/cputime.c | 13 ++++++++----- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index d5d0733..4ae19be 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 40f5816..2e885e8 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 = ¤t->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);