Turn the full dynticks cputime clock source to return nsec while keeping its very internals jiffies based for performance reasons.
Cc: Benjamin Herrenschmidt <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Martin Schwidefsky <[email protected]> Cc: Tony Luck <[email protected]> Cc: Fenghua Yu <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Stanislaw Gruszka <[email protected]> Cc: Wanpeng Li <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> --- kernel/sched/cputime.c | 31 ++++++++++++------------------- 1 file changed, 12 insertions(+), 19 deletions(-) diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 8d9fac7..737a22b 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -679,20 +679,20 @@ 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 cputime_t vtime_delta(struct task_struct *tsk) +static u64 vtime_delta(struct task_struct *tsk) { unsigned long now = READ_ONCE(jiffies); if (time_before(now, (unsigned long)tsk->vtime_snap)) return 0; - return jiffies_to_cputime(now - tsk->vtime_snap); + return jiffies_to_nsecs(now - tsk->vtime_snap); } -static cputime_t get_vtime_delta(struct task_struct *tsk) +static u64 get_vtime_delta(struct task_struct *tsk) { unsigned long now = READ_ONCE(jiffies); - cputime_t delta, other; + u64 delta, other; /* * Unlike tick based timing, vtime based timing never has lost @@ -701,7 +701,7 @@ static cputime_t 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_cputime(now - tsk->vtime_snap); + delta = jiffies_to_nsecs(now - tsk->vtime_snap); other = account_other_time(delta); WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE); tsk->vtime_snap = now; @@ -711,9 +711,7 @@ static cputime_t get_vtime_delta(struct task_struct *tsk) static void __vtime_account_system(struct task_struct *tsk) { - cputime_t delta_cpu = get_vtime_delta(tsk); - - account_system_time(tsk, irq_count(), cputime_to_nsecs(delta_cpu)); + account_system_time(tsk, irq_count(), get_vtime_delta(tsk)); } void vtime_account_system(struct task_struct *tsk) @@ -728,15 +726,12 @@ void vtime_account_system(struct task_struct *tsk) void vtime_account_user(struct task_struct *tsk) { - cputime_t delta_cpu; + u64 delta_cpu; write_seqcount_begin(&tsk->vtime_seqcount); tsk->vtime_snap_whence = VTIME_SYS; - if (vtime_delta(tsk)) { - u64 nsecs; - delta_cpu = get_vtime_delta(tsk); - account_user_time(tsk, cputime_to_nsecs(delta_cpu)); - } + if (vtime_delta(tsk)) + account_user_time(tsk, get_vtime_delta(tsk)); write_seqcount_end(&tsk->vtime_seqcount); } @@ -777,9 +772,7 @@ EXPORT_SYMBOL_GPL(vtime_guest_exit); void vtime_account_idle(struct task_struct *tsk) { - cputime_t delta_cpu = get_vtime_delta(tsk); - - account_idle_time(cputime_to_nsecs(delta_cpu)); + account_idle_time(get_vtime_delta(tsk)); } void arch_vtime_task_switch(struct task_struct *prev) @@ -819,7 +812,7 @@ u64 task_gtime(struct task_struct *t) gtime = t->gtime; if (t->vtime_snap_whence == VTIME_SYS && t->flags & PF_VCPU) - gtime += cputime_to_nsecs(vtime_delta(t)); + gtime += vtime_delta(t); } while (read_seqcount_retry(&t->vtime_seqcount, seq)); @@ -852,7 +845,7 @@ void task_cputime(struct task_struct *t, u64 *utime, u64 *stime) if (t->vtime_snap_whence == VTIME_INACTIVE || is_idle_task(t)) continue; - delta = cputime_to_nsecs(vtime_delta(t)); + delta = vtime_delta(t); /* * Task runs either in user or kernel space, add pending nohz time to -- 2.7.4
