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[PATCH] s390: cputime misaccounting

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finish_arch_switch needs to update the user cpu time as well, not just the
system cpu time.  Otherwise the partial user cpu time of a process that is
stored in the lowcore will be (mis-)accounted to the next process.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Martin Schwidefsky 2006-01-14 13:21:03 -08:00 committed by Linus Torvalds
parent bcc132651d
commit 1f1c12afe5
4 changed files with 30 additions and 8 deletions
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2
arch/s390/kernel/time.c
View file

@ -214,7 +214,7 @@ void account_ticks(struct pt_regs *regs)
#endif
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
account_user_vtime(current);
account_tick_vtime(current);
#else
while (ticks--)
update_process_times(user_mode(regs));

27
arch/s390/kernel/vtime.c
View file

@ -32,7 +32,7 @@ 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_user_vtime(struct task_struct *tsk)
void account_tick_vtime(struct task_struct *tsk)
{
cputime_t cputime;
__u64 timer, clock;
@ -72,6 +72,31 @@ void account_user_vtime(struct task_struct *tsk)
run_posix_cpu_timers(tsk);
}
/*
* Update process times based on virtual cpu times stored by entry.S
* to the lowcore fields user_timer, system_timer & steal_clock.
*/
void account_vtime(struct task_struct *tsk)
{
cputime_t cputime;
__u64 timer;
timer = S390_lowcore.last_update_timer;
asm volatile (" STPT %0" /* Store current cpu timer value */
: "=m" (S390_lowcore.last_update_timer) );
S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
cputime = S390_lowcore.user_timer >> 12;
S390_lowcore.user_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
account_user_time(tsk, cputime);
cputime = S390_lowcore.system_timer >> 12;
S390_lowcore.system_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
account_system_time(tsk, 0, cputime);
}
/*
* Update process times based on virtual cpu times stored by entry.S
* to the lowcore fields user_timer, system_timer & steal_clock.

5
include/asm-s390/system.h
View file

@ -115,13 +115,14 @@ static inline void sched_cacheflush(void)
}
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
extern void account_user_vtime(struct task_struct *);
extern void account_vtime(struct task_struct *);
extern void account_tick_vtime(struct task_struct *);
extern void account_system_vtime(struct task_struct *);
#endif
#define finish_arch_switch(prev) do { \
set_fs(current->thread.mm_segment); \
account_system_vtime(prev); \
account_vtime(prev); \
} while (0)
#define nop() __asm__ __volatile__ ("nop")

4
include/linux/hardirq.h
View file

@ -93,10 +93,6 @@ extern void synchronize_irq(unsigned int irq);
struct task_struct;
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
static inline void account_user_vtime(struct task_struct *tsk)
{
}
static inline void account_system_vtime(struct task_struct *tsk)
{
}