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sched/vtime: Bring up complete kcpustat accessor

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Many callsites want to fetch the values of system, user, user_nice, guest
or guest_nice kcpustat fields altogether or at least a pair of these.

In that case calling kcpustat_field() for each requested field brings
unecessary overhead when we could fetch all of them in a row.

So provide kcpustat_cpu_fetch() that fetches the whole kcpustat array
in a vtime safe way under the same RCU and seqcount block.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Link: https://lkml.kernel.org/r/20191121024430.19938-3-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Frederic Weisbecker
2019-11-21 03:44:26 +01:00
committed by Ingo Molnar
parent 5a1c95580f
commit 74722bb223
2 changed files with 123 additions and 20 deletions
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7
include/linux/kernel_stat.h
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@@ -81,12 +81,19 @@ static inline unsigned int kstat_cpu_irqs_sum(unsigned int cpu)
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
extern u64 kcpustat_field(struct kernel_cpustat *kcpustat,
enum cpu_usage_stat usage, int cpu);
extern void kcpustat_cpu_fetch(struct kernel_cpustat *dst, int cpu);
#else
static inline u64 kcpustat_field(struct kernel_cpustat *kcpustat,
enum cpu_usage_stat usage, int cpu)
{
return kcpustat->cpustat[usage];
}
static inline void kcpustat_cpu_fetch(struct kernel_cpustat *dst, int cpu)
{
*dst = kcpustat_cpu(cpu);
}
#endif
extern void account_user_time(struct task_struct *, u64);