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authorFrederic Weisbecker <fweisbec@gmail.com>2017-01-31 04:09:42 +0100
committerIngo Molnar <mingo@kernel.org>2017-02-01 09:13:59 +0100
commitbfce1d6006f383fbb55a89580af37819a77195b7 (patch)
treefbee27464b9c3721095b36601e5c81c450776b58 /kernel/sched/cputime.c
parent2b1f967d80e8e5d7361f0e1654c842869570f573 (diff)
downloadlinux-bfce1d6006f383fbb55a89580af37819a77195b7.tar.bz2
sched/cputime, vtime: Return nsecs instead of cputime_t to account
Turn the full dynticks cputime clock source to return nsec while keeping its very internals jiffies based for performance reasons. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-27-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/cputime.c')
-rw-r--r--kernel/sched/cputime.c31
1 files changed, 11 insertions, 20 deletions
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index f3a56bfa745f..2ecec3a4f1ee 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -678,20 +678,20 @@ 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
@@ -700,7 +700,7 @@ 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;
@@ -710,9 +710,7 @@ 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)
@@ -727,15 +725,10 @@ void vtime_account_system(struct task_struct *tsk)
void vtime_account_user(struct task_struct *tsk)
{
- cputime_t 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);
}
@@ -776,9 +769,7 @@ 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)
@@ -818,7 +809,7 @@ 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));
@@ -851,7 +842,7 @@ 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