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sched/cputime: Add steal time support to full dynticks CPU time accounting 

This patch adds guest steal-time support to full dynticks CPU
time accounting. After the following commit:

ff9a9b4c43 ("sched, time: Switch VIRT_CPU_ACCOUNTING_GEN to jiffy granularity")

... time sampling became jiffy based, even if we do the sampling from the
context tracking code, so steal_account_process_tick() can be reused
to account how many 'ticks' are stolen-time, after the last accumulation.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1465813966-3116-4-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Wanpeng Li 2016-06-13 18:32:46 +08:00 committed by Ingo Molnar
parent 3d89e5478b
commit 807e5b8068
1 changed files with 9 additions and 7 deletions
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16
kernel/sched/cputime.c
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@ -257,7 +257,7 @@ void account_idle_time(cputime_t cputime)
cpustat[CPUTIME_IDLE] += (__force u64) cputime;
}
static __always_inline bool steal_account_process_tick(void)
static __always_inline unsigned long steal_account_process_tick(unsigned long max_jiffies)
{
#ifdef CONFIG_PARAVIRT
if (static_key_false(&paravirt_steal_enabled)) {
@ -272,14 +272,14 @@ static __always_inline bool steal_account_process_tick(void)
* time in jiffies. Lets cast the result to jiffies
* granularity and account the rest on the next rounds.
*/
steal_jiffies = nsecs_to_jiffies(steal);
steal_jiffies = min(nsecs_to_jiffies(steal), max_jiffies);
this_rq()->prev_steal_time += jiffies_to_nsecs(steal_jiffies);
account_steal_time(jiffies_to_cputime(steal_jiffies));
return steal_jiffies;
}
#endif
return false;
return 0;
}
/*
@ -346,7 +346,7 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
u64 cputime = (__force u64) cputime_one_jiffy;
u64 *cpustat = kcpustat_this_cpu->cpustat;
if (steal_account_process_tick())
if (steal_account_process_tick(ULONG_MAX))
return;
cputime *= ticks;
@ -477,7 +477,7 @@ void account_process_tick(struct task_struct *p, int user_tick)
return;
}
if (steal_account_process_tick())
if (steal_account_process_tick(ULONG_MAX))
return;
if (user_tick)
@ -681,12 +681,14 @@ static cputime_t vtime_delta(struct task_struct *tsk)
static cputime_t get_vtime_delta(struct task_struct *tsk)
{
unsigned long now = READ_ONCE(jiffies);
unsigned long delta = now - tsk->vtime_snap;
unsigned long delta_jiffies, steal_jiffies;
delta_jiffies = now - tsk->vtime_snap;
steal_jiffies = steal_account_process_tick(delta_jiffies);
WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE);
tsk->vtime_snap = now;
return jiffies_to_cputime(delta);
return jiffies_to_cputime(delta_jiffies - steal_jiffies);
}
static void __vtime_account_system(struct task_struct *tsk)