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authorPaul Mackerras <paulus@samba.org>2007-11-09 22:39:38 +0100
committerIngo Molnar <mingo@elte.hu>2007-11-09 22:39:38 +0100
commitfa13a5a1f25f671d084d8884be96fc48d9b68275 (patch)
tree97dae05bb5baef806a6dcbeed8b7eb5bdc61e4ae /arch/s390
parent9a41785cc43d88397f787a651ed7286a33f8462f (diff)
downloadlinux-fa13a5a1f25f671d084d8884be96fc48d9b68275.tar.gz
sched: restore deterministic CPU accounting on powerpc
Since powerpc started using CONFIG_GENERIC_CLOCKEVENTS, the
deterministic CPU accounting (CONFIG_VIRT_CPU_ACCOUNTING) has been
broken on powerpc, because we end up counting user time twice: once in
timer_interrupt() and once in update_process_times().

This fixes the problem by pulling the code in update_process_times
that updates utime and stime into a separate function called
account_process_tick.  If CONFIG_VIRT_CPU_ACCOUNTING is not defined,
there is a version of account_process_tick in kernel/timer.c that
simply accounts a whole tick to either utime or stime as before.  If
CONFIG_VIRT_CPU_ACCOUNTING is defined, then arch code gets to
implement account_process_tick.

This also lets us simplify the s390 code a bit; it means that the s390
timer interrupt can now call update_process_times even when
CONFIG_VIRT_CPU_ACCOUNTING is turned on, and can just implement a
suitable account_process_tick().

account_process_tick() now takes the task_struct * as an argument.
Tested both with and without CONFIG_VIRT_CPU_ACCOUNTING.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/kernel/time.c4
-rw-r--r--arch/s390/kernel/vtime.c8
2 files changed, 1 insertions, 11 deletions
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index a963fe81359e..22b800ce2126 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -145,12 +145,8 @@ void account_ticks(u64 time)
 	do_timer(ticks);
 #endif
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
-	account_tick_vtime(current);
-#else
 	while (ticks--)
 		update_process_times(user_mode(get_irq_regs()));
-#endif
 
 	s390_do_profile();
 }
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 84ff78de6bac..c5f05b3fb2c3 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -32,7 +32,7 @@ static DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer);
  * Update process times based on virtual cpu times stored by entry.S
  * to the lowcore fields user_timer, system_timer & steal_clock.
  */
-void account_tick_vtime(struct task_struct *tsk)
+void account_process_tick(struct task_struct *tsk, int user_tick)
 {
 	cputime_t cputime;
 	__u64 timer, clock;
@@ -64,12 +64,6 @@ void account_tick_vtime(struct task_struct *tsk)
 		S390_lowcore.steal_clock -= cputime << 12;
 		account_steal_time(tsk, cputime);
 	}
-
-	run_local_timers();
-	if (rcu_pending(smp_processor_id()))
-		rcu_check_callbacks(smp_processor_id(), rcu_user_flag);
-	scheduler_tick();
- 	run_posix_cpu_timers(tsk);
 }
 
 /*