[tip:sched/core] tsacct: Convert obsolete cputime type to nsecs

[tip-bot for Frederic Weisbecker <tipbot@zytor.com>]

Commit-ID:  605dc2b31a2ab235570107cb650036b41e741165
Gitweb:     http://git.kernel.org/tip/605dc2b31a2ab235570107cb650036b41e741165
Author:     Frederic Weisbecker <fweisbec@gmail.com>
AuthorDate: Tue, 31 Jan 2017 04:09:30 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 1 Feb 2017 09:13:52 +0100

tsacct: Convert obsolete cputime type to nsecs

Use the new nsec based cputime accessors as part of the whole cputime
conversion from cputime_t to nsecs.

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/1485832191-26889-15-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 include/linux/sched.h |  2 +-
 kernel/tsacct.c       | 27 ++++++++++++---------------
 2 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 75fc773..dc44366 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1815,7 +1815,7 @@ struct task_struct {
 #if defined(CONFIG_TASK_XACCT)
 	u64 acct_rss_mem1;	/* accumulated rss usage */
 	u64 acct_vm_mem1;	/* accumulated virtual memory usage */
-	cputime_t acct_timexpd;	/* stime + utime since last update */
+	u64 acct_timexpd;	/* stime + utime since last update */
 #endif
 #ifdef CONFIG_CPUSETS
 	nodemask_t mems_allowed;	/* Protected by alloc_lock */
diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 040d0a6..5c21f05 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -31,7 +31,7 @@ void bacct_add_tsk(struct user_namespace *user_ns,
 		   struct taskstats *stats, struct task_struct *tsk)
 {
 	const struct cred *tcred;
-	cputime_t utime, stime, utimescaled, stimescaled;
+	u64 utime, stime, utimescaled, stimescaled;
 	u64 delta;
 
 	BUILD_BUG_ON(TS_COMM_LEN < TASK_COMM_LEN);
@@ -66,13 +66,13 @@ void bacct_add_tsk(struct user_namespace *user_ns,
 		task_tgid_nr_ns(rcu_dereference(tsk->real_parent), pid_ns) : 0;
 	rcu_read_unlock();
 
-	task_cputime_t(tsk, &utime, &stime);
-	stats->ac_utime = cputime_to_usecs(utime);
-	stats->ac_stime = cputime_to_usecs(stime);
+	task_cputime(tsk, &utime, &stime);
+	stats->ac_utime = div_u64(utime, NSEC_PER_USEC);
+	stats->ac_stime = div_u64(stime, NSEC_PER_USEC);
 
-	task_cputime_t_scaled(tsk, &utimescaled, &stimescaled);
-	stats->ac_utimescaled = cputime_to_usecs(utimescaled);
-	stats->ac_stimescaled = cputime_to_usecs(stimescaled);
+	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
+	stats->ac_utimescaled = div_u64(utimescaled, NSEC_PER_USEC);
+	stats->ac_stimescaled = div_u64(stimescaled, NSEC_PER_USEC);
 
 	stats->ac_minflt = tsk->min_flt;
 	stats->ac_majflt = tsk->maj_flt;
@@ -123,18 +123,15 @@ void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
 #undef MB
 
 static void __acct_update_integrals(struct task_struct *tsk,
-				    cputime_t utime, cputime_t stime)
+				    u64 utime, u64 stime)
 {
-	cputime_t time, dtime;
-	u64 delta;
+	u64 time, delta;
 
 	if (!likely(tsk->mm))
 		return;
 
 	time = stime + utime;
-	dtime = time - tsk->acct_timexpd;
-	/* Avoid division: cputime_t is often in nanoseconds already. */
-	delta = cputime_to_nsecs(dtime);
+	delta = time - tsk->acct_timexpd;
 
 	if (delta < TICK_NSEC)
 		return;
@@ -155,11 +152,11 @@ static void __acct_update_integrals(struct task_struct *tsk,
  */
 void acct_update_integrals(struct task_struct *tsk)
 {
-	cputime_t utime, stime;
+	u64 utime, stime;
 	unsigned long flags;
 
 	local_irq_save(flags);
-	task_cputime_t(tsk, &utime, &stime);
+	task_cputime(tsk, &utime, &stime);
 	__acct_update_integrals(tsk, utime, stime);
 	local_irq_restore(flags);
 }