Commit dbe93371 authored Apr 20, 2020 by Muchun Song Committed by Peter Zijlstra May 19, 2020

sched/cpuacct: Fix charge cpuacct.usage_sys



The user_mode(task_pt_regs(tsk)) always return true for
user thread, and false for kernel thread. So it means that
the cpuacct.usage_sys is the time that kernel thread uses
not the time that thread uses in the kernel mode. We can
try get_irq_regs() first, if it is NULL, then we can fall
back to task_pt_regs().

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200420070453.76815-1-songmuchun@bytedance.com

parent 04f5c362

kernel/sched/cpuacct.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -5,6 +5,7 @@
		* Based on the work by Paul Menage (menage@google.com) and Balbir Singh
		* (balbir@in.ibm.com).
		*/
		#include <asm/irq_regs.h>
		#include "sched.h"

		/* Time spent by the tasks of the CPU accounting group executing in ... */
		@@ -339,7 +340,7 @@ void cpuacct_charge(struct task_struct *tsk, u64 cputime)
		{
		struct cpuacct *ca;
		int index = CPUACCT_STAT_SYSTEM;
		struct pt_regs *regs = task_pt_regs(tsk);
		struct pt_regs *regs = get_irq_regs() ? : task_pt_regs(tsk);

		if (regs && user_mode(regs))
		index = CPUACCT_STAT_USER;

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