linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH][RFC] sched/cpuacct: Fix cpuacct charge
@ 2021-07-20  6:04 Li RongQing
  2021-07-29 10:19 ` Peter Zijlstra
  0 siblings, 1 reply; 6+ messages in thread
From: Li RongQing @ 2021-07-20  6:04 UTC (permalink / raw)
  To: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann,
	rostedt, bsegall, mgorman, bristot, linux-kernel, songmuchun

get_irq_regs only work for current running cpu, but the task, whose
cpuacct will be charged, maybe run different cpu, like Cpu 2 wake
up a kernel thread to CPU 3, cause CPU 3 task are charged with the
following stack

  cpuacct_charge+0xd8/0x100
  update_curr+0xe1/0x1e0
  enqueue_entity+0x144/0x6e0
  enqueue_task_fair+0x93/0x900
  ttwu_do_activate+0x4b/0x90
  try_to_wake_up+0x20b/0x530
  ? update_dl_rq_load_avg+0x10f/0x210
  swake_up_locked.part.1+0x13/0x40
  swake_up_one+0x27/0x40
  rcu_process_callbacks+0x484/0x4f0
  ? run_rebalance_domains_bt+0x5a/0x180
  __do_softirq+0xe3/0x308
  irq_exit+0xf0/0x100
  smp_apic_timer_interrupt+0x74/0x160
  apic_timer_interrupt+0xf/0x20
  </IRQ>
 RIP: 0033:0x456947

so define a get_irq_regs_cpu which returns the required cpu irq registers

BUT it should be not safe, and do not know what it should be like in MIPS?

Fixes: dbe9337109c2 "(sched/cpuacct: Fix charge cpuacct.usage_sys)"
Co-developed-by: Zhao Jie <zhaojie17@baidu.com>
Signed-off-by: Zhao Jie <zhaojie17@baidu.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
 include/asm-generic/irq_regs.h | 5 +++++
 kernel/sched/cpuacct.c         | 3 ++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/asm-generic/irq_regs.h b/include/asm-generic/irq_regs.h
index 2e7c6e8..93e2579 100644
--- a/include/asm-generic/irq_regs.h
+++ b/include/asm-generic/irq_regs.h
@@ -21,6 +21,11 @@ static inline struct pt_regs *get_irq_regs(void)
 	return __this_cpu_read(__irq_regs);
 }
 
+static inline struct pt_regs *get_irq_regs_cpu(int cpu)
+{
+	return per_cpu(__irq_regs, cpu);
+}
+
 static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs)
 {
 	struct pt_regs *old_regs;
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index 893eece..8b96058 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -340,7 +340,8 @@ void cpuacct_charge(struct task_struct *tsk, u64 cputime)
 {
 	struct cpuacct *ca;
 	int index = CPUACCT_STAT_SYSTEM;
-	struct pt_regs *regs = get_irq_regs() ? : task_pt_regs(tsk);
+	int cpu = task_cpu(tsk);
+	struct pt_regs *regs = get_irq_regs_cpu(cpu) ? : task_pt_regs(tsk);
 
 	if (regs && user_mode(regs))
 		index = CPUACCT_STAT_USER;
-- 
2.9.4


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-08-18 15:34 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-07-20  6:04 [PATCH][RFC] sched/cpuacct: Fix cpuacct charge Li RongQing
2021-07-29 10:19 ` Peter Zijlstra
2021-07-30  8:16   ` 答复: " Li,Rongqing
2021-08-16 16:21     ` Daniel Jordan
2021-08-17  3:55       ` 答复: " Li,Rongqing
2021-08-18 15:33         ` Daniel Jordan

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).