From: Martin Schwidefsky <[email protected]>
[patch 11/13] s390: cputime misaccounting.
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 <[email protected]>
---
arch/s390/kernel/time.c | 2 +-
arch/s390/kernel/vtime.c | 27 ++++++++++++++++++++++++++-
include/asm-s390/system.h | 5 +++--
include/linux/hardirq.h | 4 ----
4 files changed, 30 insertions(+), 8 deletions(-)
diff -urpN linux-2.6/arch/s390/kernel/time.c linux-2.6-patched/arch/s390/kernel/time.c
--- linux-2.6/arch/s390/kernel/time.c 2006-01-03 04:21:10.000000000 +0100
+++ linux-2.6-patched/arch/s390/kernel/time.c 2006-01-12 15:44:01.000000000 +0100
@@ -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));
diff -urpN linux-2.6/arch/s390/kernel/vtime.c linux-2.6-patched/arch/s390/kernel/vtime.c
--- linux-2.6/arch/s390/kernel/vtime.c 2006-01-03 04:21:10.000000000 +0100
+++ linux-2.6-patched/arch/s390/kernel/vtime.c 2006-01-12 15:44:01.000000000 +0100
@@ -32,7 +32,7 @@ DEFINE_PER_CPU(struct vtimer_queue, virt
* 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;
@@ -76,6 +76,31 @@ void account_user_vtime(struct task_stru
* 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.
+ */
void account_system_vtime(struct task_struct *tsk)
{
cputime_t cputime;
diff -urpN linux-2.6/include/asm-s390/system.h linux-2.6-patched/include/asm-s390/system.h
--- linux-2.6/include/asm-s390/system.h 2006-01-03 04:21:10.000000000 +0100
+++ linux-2.6-patched/include/asm-s390/system.h 2006-01-12 15:44:01.000000000 +0100
@@ -105,13 +105,14 @@ static inline void restore_access_regs(u
} while (0)
#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")
diff -urpN linux-2.6/include/linux/hardirq.h linux-2.6-patched/include/linux/hardirq.h
--- linux-2.6/include/linux/hardirq.h 2006-01-03 04:21:10.000000000 +0100
+++ linux-2.6-patched/include/linux/hardirq.h 2006-01-12 15:44:01.000000000 +0100
@@ -93,10 +93,6 @@ extern void synchronize_irq(unsigned int
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)
{
}