2016-05-18 17:46 GMT+08:00 Mika Penttilä <mika.penttila@xxxxxxxxxxxx>:
> On 05/18/2016 11:28 AM, Wanpeng Li wrote:
>> From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
>>
>> This patch adds steal guest time support to full dynticks CPU
>> time accounting. After 'commit ff9a9b4c4334 ("sched, time: Switch
>> VIRT_CPU_ACCOUNTING_GEN to jiffy granularity")', time is jiffy
>> based sampling even if it's still listened to ring boundaries, so
>> steal_account_process_tick() is reused to account how much 'ticks'
>> are steal time after the last accumulation.
>>
>> Suggested-by: Rik van Riel <riel@xxxxxxxxxx>
>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>> Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
>> Cc: Rik van Riel <riel@xxxxxxxxxx>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
>> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
>> Cc: Radim <rkrcmar@xxxxxxxxxx>
>> Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
>> ---
>> v1 -> v2:
>> * fix divide zero bug, thanks Rik
>>
>> kernel/sched/cputime.c | 13 +++++++++++--
>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
>> index 75f98c5..bfa50a0 100644
>> --- a/kernel/sched/cputime.c
>> +++ b/kernel/sched/cputime.c
>> @@ -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(void)
>> {
>> #ifdef CONFIG_PARAVIRT
>> if (static_key_false(¶virt_steal_enabled)) {
>> @@ -279,7 +279,7 @@ static __always_inline bool steal_account_process_tick(void)
>> return steal_jiffies;
>> }
>> #endif
>> - return false;
>> + return 0;
>> }
>>
>> /*
>> @@ -691,8 +691,12 @@ static cputime_t get_vtime_delta(struct task_struct *tsk)
>>
>> static void __vtime_account_system(struct task_struct *tsk)
>> {
>> + unsigned long steal_time = steal_account_process_tick();
>> cputime_t delta_cpu = get_vtime_delta(tsk);
>>
>> + if (steal_time >= delta_cpu)
>> + return;
>> + delta_cpu -= steal_time;
>> account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
>> }
>>
>> @@ -723,7 +727,12 @@ void vtime_account_user(struct task_struct *tsk)
>> write_seqcount_begin(&tsk->vtime_seqcount);
>> tsk->vtime_snap_whence = VTIME_SYS;
>> if (vtime_delta(tsk)) {
>> + unsigned long steal_time = steal_account_process_tick();
>> delta_cpu = get_vtime_delta(tsk);
>
>
> afaik steal_account_process_tick() returns jiffies and get_vtime_delta() cputime, so can't mix them like this : ?
You are right, thanks for your review. I will fix it.
Regards,
Wanpeng Li
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