cputime: Consolidate vtime handling on context switch

The archs that implement virtual cputime accounting all
flush the cputime of a task when it gets descheduled
and sometimes set up some ground initialization for the
next task to account its cputime.

These archs all put their own hooks in their context
switch callbacks and handle the off-case themselves.

Consolidate this by creating a new account_switch_vtime()
callback called in generic code right after a context switch
and that these archs must implement to flush the prev task
cputime and initialize the next task cputime related state.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

diff --git a/arch/ia64/include/asm/switch_to.h b/arch/ia64/include/asm/switch_to.h
index cb2412fcd17f234af87600094507fa230cba51b4..d38c7ea5eea5d129a32132583c2bbcb8a319bcb9 100644 (file)
--- a/arch/ia64/include/asm/switch_to.h
+++ b/arch/ia64/include/asm/switch_to.h
@@ -30,13 +30,6 @@ extern struct task_struct *ia64_switch_to (void *next_task);
 extern void ia64_save_extra (struct task_struct *task);
 extern void ia64_load_extra (struct task_struct *task);
 
-#ifdef CONFIG_VIRT_CPU_ACCOUNTING
-extern void ia64_account_on_switch (struct task_struct *prev, struct task_struct *next);
-# define IA64_ACCOUNT_ON_SWITCH(p,n) ia64_account_on_switch(p,n)
-#else
-# define IA64_ACCOUNT_ON_SWITCH(p,n)
-#endif
-
 #ifdef CONFIG_PERFMON
   DECLARE_PER_CPU(unsigned long, pfm_syst_info);
 # define PERFMON_IS_SYSWIDE() (__get_cpu_var(pfm_syst_info) & 0x1)
@@ -49,7 +42,6 @@ extern void ia64_account_on_switch (struct task_struct *prev, struct task_struct
         || PERFMON_IS_SYSWIDE())
 
 #define __switch_to(prev,next,last) do {                                                        \
-       IA64_ACCOUNT_ON_SWITCH(prev, next);                                                      \
        if (IA64_HAS_EXTRA_STATE(prev))                                                          \
                ia64_save_extra(prev);                                                           \
        if (IA64_HAS_EXTRA_STATE(next))                                                          \

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index ecc904b33c5f2935fa1285d8f4cdac9515a3a84d..6247197b987782341bdc70465418094019dacb93 100644 (file)
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -88,10 +88,10 @@ extern cputime_t cycle_to_cputime(u64 cyc);
  * accumulated times to the current process, and to prepare accounting on
  * the next process.
  */
-void ia64_account_on_switch(struct task_struct *prev, struct task_struct *next)
+void account_switch_vtime(struct task_struct *prev)
 {
        struct thread_info *pi = task_thread_info(prev);
-       struct thread_info *ni = task_thread_info(next);
+       struct thread_info *ni = task_thread_info(current);
        cputime_t delta_stime, delta_utime;
        __u64 now;
 

diff --git a/arch/powerpc/include/asm/time.h b/arch/powerpc/include/asm/time.h
index 3b4b4a8da922fc4801d51bae86fc8e2b8e810108..c1f267694acbecd7f072245f57199faa0594e3c6 100644 (file)
--- a/arch/powerpc/include/asm/time.h
+++ b/arch/powerpc/include/asm/time.h
@@ -197,12 +197,6 @@ struct cpu_usage {
 
 DECLARE_PER_CPU(struct cpu_usage, cpu_usage_array);
 
-#if defined(CONFIG_VIRT_CPU_ACCOUNTING)
-#define account_process_vtime(tsk)             account_process_tick(tsk, 0)
-#else
-#define account_process_vtime(tsk)             do { } while (0)
-#endif
-
 extern void secondary_cpu_time_init(void);
 
 DECLARE_PER_CPU(u64, decrementers_next_tb);

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 710f400476deb8461a98a1342c6ee1b669fbe686..d73fa999b47bdc775a1848e5e25012c0316955d0 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -514,9 +514,6 @@ struct task_struct *__switch_to(struct task_struct *prev,
 
        local_irq_save(flags);
 
-       account_system_vtime(current);
-       account_process_vtime(current);
-
        /*
         * We can't take a PMU exception inside _switch() since there is a
         * window where the kernel stack SLB and the kernel stack are out

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index be171ee73bf8cd3bef83630fbc031ad4f29410e7..49da7f06e643d6474691764003e4ea0ac2cd6f43 100644 (file)
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -366,6 +366,12 @@ void account_process_tick(struct task_struct *tsk, int user_tick)
        account_user_time(tsk, utime, utimescaled);
 }
 
+void account_switch_vtime(struct task_struct *prev)
+{
+       account_system_vtime(prev);
+       account_process_tick(prev, 0);
+}
+
 #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
 #define calc_cputime_factors()
 #endif

diff --git a/arch/s390/include/asm/switch_to.h b/arch/s390/include/asm/switch_to.h
index f223068b7822601ffff64b07ca4f6e412cff554f..e7f9b3d04fa148e0bca2093b184eed4ac7fddf4b 100644 (file)
--- a/arch/s390/include/asm/switch_to.h
+++ b/arch/s390/include/asm/switch_to.h
@@ -89,12 +89,10 @@ static inline void restore_access_regs(unsigned int *acrs)
        prev = __switch_to(prev,next);                                  \
 } while (0)
 
-extern void account_vtime(struct task_struct *, struct task_struct *);
 extern void account_tick_vtime(struct task_struct *);
 
 #define finish_arch_switch(prev) do {                                       \
        set_fs(current->thread.mm_segment);                                  \
-       account_vtime(prev, current);                                        \
 } while (0)
 
 #endif /* __ASM_SWITCH_TO_H */

diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 4fc97b40a6e1a3fe48a9ca108cf0227e1fa637b9..449ac22cc71bd401485c95465ad55f67d944a853 100644 (file)
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -99,7 +99,7 @@ static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
        return virt_timer_forward(user + system);
 }
 
-void account_vtime(struct task_struct *prev, struct task_struct *next)
+void account_switch_vtime(struct task_struct *prev)
 {
        struct thread_info *ti;
 
@@ -107,7 +107,7 @@ void account_vtime(struct task_struct *prev, struct task_struct *next)
        ti = task_thread_info(prev);
        ti->user_timer = S390_lowcore.user_timer;
        ti->system_timer = S390_lowcore.system_timer;
-       ti = task_thread_info(next);
+       ti = task_thread_info(current);
        S390_lowcore.user_timer = ti->user_timer;
        S390_lowcore.system_timer = ti->system_timer;
 }

diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 2fbd9053c2df6477a425567c49014ea3328f9038..bbe5d15d6597113c4e44b8180b173f53269ebe97 100644 (file)
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -130,4 +130,10 @@ extern void account_process_tick(struct task_struct *, int user);
 extern void account_steal_ticks(unsigned long ticks);
 extern void account_idle_ticks(unsigned long ticks);
 
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+extern void account_switch_vtime(struct task_struct *prev);
+#else
+static inline void account_switch_vtime(struct task_struct *prev) { }
+#endif
+
 #endif /* _LINUX_KERNEL_STAT_H */

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ae3bcaa3afbf14940d5e19a41c878a7df4a9904d..78d9c965433a5cb6309e35110f19a6cefca7a27a 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1796,6 +1796,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
         *              Manfred Spraul <manfred@colorfullife.com>
         */
        prev_state = prev->state;
+       account_switch_vtime(prev);
        finish_arch_switch(prev);
 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
        local_irq_disable();