Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer and time updates from Thomas Gleixner:
 "A rather large update of timers, timekeeping & co

   - Core timekeeping code is year-2038 safe now for 32bit machines.
     Now we just need to fix all in kernel users and the gazillion of
     user space interfaces which rely on timespec/timeval :)

   - Better cache layout for the timekeeping internal data structures.

   - Proper nanosecond based interfaces for in kernel users.

   - Tree wide cleanup of code which wants nanoseconds but does hoops
     and loops to convert back and forth from timespecs.  Some of it
     definitely belongs into the ugly code museum.

   - Consolidation of the timekeeping interface zoo.

   - A fast NMI safe accessor to clock monotonic for tracing.  This is a
     long standing request to support correlated user/kernel space
     traces.  With proper NTP frequency correction it's also suitable
     for correlation of traces accross separate machines.

   - Checkpoint/restart support for timerfd.

   - A few NOHZ[_FULL] improvements in the [hr]timer code.

   - Code move from kernel to kernel/time of all time* related code.

   - New clocksource/event drivers from the ARM universe.  I'm really
     impressed that despite an architected timer in the newer chips SoC
     manufacturers insist on inventing new and differently broken SoC
     specific timers.

[ Ed. "Impressed"? I don't think that word means what you think it means ]

   - Another round of code move from arch to drivers.  Looks like most
     of the legacy mess in ARM regarding timers is sorted out except for
     a few obnoxious strongholds.

   - The usual updates and fixlets all over the place"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
  timekeeping: Fixup typo in update_vsyscall_old definition
  clocksource: document some basic timekeeping concepts
  timekeeping: Use cached ntp_tick_length when accumulating error
  timekeeping: Rework frequency adjustments to work better w/ nohz
  timekeeping: Minor fixup for timespec64->timespec assignment
  ftrace: Provide trace clocks monotonic
  timekeeping: Provide fast and NMI safe access to CLOCK_MONOTONIC
  seqcount: Add raw_write_seqcount_latch()
  seqcount: Provide raw_read_seqcount()
  timekeeping: Use tk_read_base as argument for timekeeping_get_ns()
  timekeeping: Create struct tk_read_base and use it in struct timekeeper
  timekeeping: Restructure the timekeeper some more
  clocksource: Get rid of cycle_last
  clocksource: Move cycle_last validation to core code
  clocksource: Make delta calculation a function
  wireless: ath9k: Get rid of timespec conversions
  drm: vmwgfx: Use nsec based interfaces
  drm: i915: Use nsec based interfaces
  timekeeping: Provide ktime_get_raw()
  hangcheck-timer: Use ktime_get_ns()
  ...

1 files changed, 3 insertions, 7 deletions

diff --git a/kernel/acct.c b/kernel/acct.c
index 808a86ff229d..a1844f14c6d6 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -458,9 +458,7 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 	acct_t ac;
 	mm_segment_t fs;
 	unsigned long flim;
-	u64 elapsed;
-	u64 run_time;
-	struct timespec uptime;
+	u64 elapsed, run_time;
 	struct tty_struct *tty;
 	const struct cred *orig_cred;
 
@@ -484,10 +482,8 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 	strlcpy(ac.ac_comm, current->comm, sizeof(ac.ac_comm));
 
 	/* calculate run_time in nsec*/
-	do_posix_clock_monotonic_gettime(&uptime);
-	run_time = (u64)uptime.tv_sec*NSEC_PER_SEC + uptime.tv_nsec;
-	run_time -= (u64)current->group_leader->start_time.tv_sec * NSEC_PER_SEC
-		       + current->group_leader->start_time.tv_nsec;
+	run_time = ktime_get_ns();
+	run_time -= current->group_leader->start_time;
 	/* convert nsec -> AHZ */
 	elapsed = nsec_to_AHZ(run_time);
 #if ACCT_VERSION==3