From: Zhen Lei <thunder.leizhen@xxxxxxxxxx> As commit aa0ce5bbc2db ("softirq: introduce statistics for softirq") mentioned, the number of one softirq can exceed 100 per second. At this rate, the 32-bit sum will overflow after 1.5 years. This problem can be avoided if the type of 'softirqs[]' is changed to u64, but the atomicity of the counting operation cannot be guaranteed on 32-bit processors. Changing to unsigned long can safely solve the problem on 64-bit processors, and it is the same as the type of 'irqs_sum'. Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx> --- fs/proc/softirqs.c | 2 +- fs/proc/stat.c | 2 +- include/linux/kernel_stat.h | 8 ++++---- kernel/rcu/tree.h | 2 +- kernel/rcu/tree_stall.h | 6 +++--- 5 files changed, 10 insertions(+), 10 deletions(-) diff --git a/fs/proc/softirqs.c b/fs/proc/softirqs.c index f4616083faef3bb..985be6904d748ab 100644 --- a/fs/proc/softirqs.c +++ b/fs/proc/softirqs.c @@ -20,7 +20,7 @@ static int show_softirqs(struct seq_file *p, void *v) for (i = 0; i < NR_SOFTIRQS; i++) { seq_printf(p, "%12s:", softirq_to_name[i]); for_each_possible_cpu(j) - seq_printf(p, " %10u", kstat_softirqs_cpu(i, j)); + seq_printf(p, " %10lu", kstat_softirqs_cpu(i, j)); seq_putc(p, '\n'); } return 0; diff --git a/fs/proc/stat.c b/fs/proc/stat.c index 84aac577a50cabb..7d40d98471d5ab2 100644 --- a/fs/proc/stat.c +++ b/fs/proc/stat.c @@ -116,7 +116,7 @@ static int show_stat(struct seq_file *p, void *v) sum += arch_irq_stat_cpu(i); for (j = 0; j < NR_SOFTIRQS; j++) { - unsigned int softirq_stat = kstat_softirqs_cpu(j, i); + unsigned long softirq_stat = kstat_softirqs_cpu(j, i); per_softirq_sums[j] += softirq_stat; sum_softirq += softirq_stat; diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h index 9935f7ecbfb9e31..b6c5723a1149cd6 100644 --- a/include/linux/kernel_stat.h +++ b/include/linux/kernel_stat.h @@ -40,7 +40,7 @@ struct kernel_cpustat { struct kernel_stat { unsigned long irqs_sum; - unsigned int softirqs[NR_SOFTIRQS]; + unsigned long softirqs[NR_SOFTIRQS]; }; DECLARE_PER_CPU(struct kernel_stat, kstat); @@ -63,15 +63,15 @@ static inline void kstat_incr_softirqs_this_cpu(unsigned int irq) __this_cpu_inc(kstat.softirqs[irq]); } -static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu) +static inline unsigned long kstat_softirqs_cpu(unsigned int irq, int cpu) { return kstat_cpu(cpu).softirqs[irq]; } -static inline unsigned int kstat_cpu_softirqs_sum(int cpu) +static inline unsigned long kstat_cpu_softirqs_sum(int cpu) { int i; - unsigned int sum = 0; + unsigned long sum = 0; for (i = 0; i < NR_SOFTIRQS; i++) sum += kstat_softirqs_cpu(i, cpu); diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 192536916f9a607..ce51640cd34f66b 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -268,7 +268,7 @@ struct rcu_data { unsigned long rcuc_activity; /* 7) Diagnostic data, including RCU CPU stall warnings. */ - unsigned int softirq_snap; /* Snapshot of softirq activity. */ + unsigned long softirq_snap; /* Snapshot of softirq activity. */ /* ->rcu_iw* fields protected by leaf rcu_node ->lock. */ struct irq_work rcu_iw; /* Check for non-irq activity. */ bool rcu_iw_pending; /* Is ->rcu_iw pending? */ diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 0ade7f9dcaa18da..d5b22700abcc385 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -446,7 +446,7 @@ static void print_cpu_stat_info(int cpu) rsr.cputime_system = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu); pr_err("\t hardirqs softirqs csw/system\n"); - pr_err("\t number: %8ld %10d %12lld\n", + pr_err("\t number: %8ld %10ld %12lld\n", kstat_cpu_irqs_sum(cpu) - rsrp->nr_hardirqs, kstat_cpu_softirqs_sum(cpu) - rsrp->nr_softirqs, nr_context_switches_cpu(cpu) - rsrp->nr_csw); @@ -498,7 +498,7 @@ static void print_cpu_stall_info(int cpu) rcuc_starved = rcu_is_rcuc_kthread_starving(rdp, &j); if (rcuc_starved) sprintf(buf, " rcuc=%ld jiffies(starved)", j); - pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%04x/%ld/%#lx softirq=%u/%u fqs=%ld%s%s\n", + pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%04x/%ld/%#lx softirq=%lu/%lu fqs=%ld%s%s\n", cpu, "O."[!!cpu_online(cpu)], "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)], @@ -575,7 +575,7 @@ static void rcu_check_gp_kthread_expired_fqs_timer(void) data_race(rcu_state.gp_flags), gp_state_getname(RCU_GP_WAIT_FQS), RCU_GP_WAIT_FQS, data_race(READ_ONCE(gpk->__state))); - pr_err("\tPossible timer handling issue on cpu=%d timer-softirq=%u\n", + pr_err("\tPossible timer handling issue on cpu=%d timer-softirq=%lu\n", cpu, kstat_softirqs_cpu(TIMER_SOFTIRQ, cpu)); } } -- 2.25.1