From 7098c1eac75dc03fdbb7249171a6e68ce6044a5a Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Thu, 19 Nov 2015 16:47:30 +0100
Subject: [PATCH] sched/cputime: Clarify vtime symbols and document them
VTIME_SLEEPING state happens either when:
1) The task is sleeping and no tickless delta is to be added on the task
cputime stats.
2) The CPU isn't running vtime at all, so the same properties of 1) applies.
Lets rename the vtime symbol to reflect both states.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1447948054-28668-4-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/sched.h | 5 ++++-
kernel/fork.c | 2 +-
kernel/sched/cputime.c | 6 +++---
3 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index f425aac633177..3533168fe7d1f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1522,8 +1522,11 @@ struct task_struct {
seqlock_t vtime_seqlock;
unsigned long long vtime_snap;
enum {
- VTIME_SLEEPING = 0,
+ /* 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_snap_whence;
#endif
diff --git a/kernel/fork.c b/kernel/fork.c
index f97f2c449f5cf..c0a13706b1a75 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1350,7 +1350,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
seqlock_init(&p->vtime_seqlock);
p->vtime_snap = 0;
- p->vtime_snap_whence = VTIME_SLEEPING;
+ p->vtime_snap_whence = VTIME_INACTIVE;
#endif
#if defined(SPLIT_RSS_COUNTING)
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 1128d4ba6c552..4a18a6ed7723f 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -680,7 +680,7 @@ static cputime_t get_vtime_delta(struct task_struct *tsk)
{
unsigned long long delta = vtime_delta(tsk);
- WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_SLEEPING);
+ WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE);
tsk->vtime_snap += delta;
/* CHECKME: always safe to convert nsecs to cputime? */
@@ -764,7 +764,7 @@ void vtime_account_idle(struct task_struct *tsk)
void arch_vtime_task_switch(struct task_struct *prev)
{
write_seqlock(&prev->vtime_seqlock);
- prev->vtime_snap_whence = VTIME_SLEEPING;
+ prev->vtime_snap_whence = VTIME_INACTIVE;
write_sequnlock(&prev->vtime_seqlock);
write_seqlock(¤t->vtime_seqlock);
@@ -829,7 +829,7 @@ fetch_task_cputime(struct task_struct *t,
*s_dst = *s_src;
/* Task is sleeping, nothing to add */
- if (t->vtime_snap_whence == VTIME_SLEEPING ||
+ if (t->vtime_snap_whence == VTIME_INACTIVE ||
is_idle_task(t))
continue;
--
2.30.2