Messages in this thread Patch in this message | | | From | Li RongQing <> | Subject | [PATCH][RFC] sched/cpuacct: Fix cpuacct charge | Date | Tue, 20 Jul 2021 14:04:41 +0800 |
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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
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