[PATCH] sched/cpuacct: Fix charge cpuacct.usage_sys incorrently.

From: Muchun Song
Date: Thu Apr 16 2020 - 10:33:18 EST


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
use get_irq_regs() instead of task_pt_regs() to fix it.

Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
kernel/sched/cpuacct.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index 6448b0438ffb2..edfc62554648e 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -5,6 +5,7 @@
* Based on the work by Paul Menage (menage@xxxxxxxxxx) and Balbir Singh
* (balbir@xxxxxxxxxx).
*/
+#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();

if (regs && user_mode(regs))
index = CPUACCT_STAT_USER;
--
2.11.0