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From: Alexei Lozovsky <me@ilammy.net>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
	Christoph Lameter <cl@linux.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org
Subject: [PATCH v2 02/12] genirq: Use unsigned long for IRQ counters
Date: Thu, 16 Sep 2021 02:58:38 +0900	[thread overview]
Message-ID: <20210915175848.162260-3-me@ilammy.net> (raw)
In-Reply-To: <20210915175848.162260-1-me@ilammy.net>

Widen the counters to unsigned long. In fact, some counters already
use unsigned long and we merely make the other ones agree. that's
one of the reasons for the change: using the same type everywhere
means that counter sum wraps around in a consistent manner,
allowing accurate accounting of the total number of interrupts.

Another aspect is simply widening the type on architectures where
this is possible (i.e., 64-bit ones). 32-bit architectures will keep
32-bit counters, 64-bit archs will be able to use 64-bit counters.
Since 64-bit counters have such huge range, it's unlikely that they
will wrap around in the first place.

Signed-off-by: Alexei Lozovsky <me@ilammy.net>
---
 fs/proc/softirqs.c          | 2 +-
 fs/proc/stat.c              | 2 +-
 include/linux/kernel_stat.h | 6 +++---
 kernel/rcu/tree.h           | 2 +-
 kernel/rcu/tree_stall.h     | 4 ++--
 5 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/proc/softirqs.c b/fs/proc/softirqs.c
index 12901dcf57e2..2bc05c23d22e 100644
--- a/fs/proc/softirqs.c
+++ b/fs/proc/softirqs.c
@@ -19,7 +19,7 @@ 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 6561a06ef905..d9d89d7a959c 100644
--- a/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@ -142,7 +142,7 @@ 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 90f2e2faf999..41541ce67dfa 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -37,7 +37,7 @@ 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);
@@ -59,7 +59,7 @@ 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 READ_ONCE(kstat_cpu(cpu).softirqs[irq]);
 }
@@ -72,7 +72,7 @@ extern unsigned int kstat_irqs_usr(unsigned int irq);
 /*
  * Number of interrupts per cpu, since bootup
  */
-static inline unsigned int kstat_cpu_irqs_sum(unsigned int cpu)
+static inline unsigned long kstat_cpu_irqs_sum(unsigned int cpu)
 {
 	return READ_ONCE(kstat_cpu(cpu).irqs_sum);
 }
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 305cf6aeb408..94e4f022f995 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -242,7 +242,7 @@ struct rcu_data {
 	char rcu_cpu_has_work;
 
 	/* 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 6c76988cc019..35e67275b5b4 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -435,7 +435,7 @@ static void print_cpu_stall_info(int cpu)
 	delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq);
 	falsepositive = rcu_is_gp_kthread_starving(NULL) &&
 			rcu_dynticks_in_eqs(rcu_dynticks_snap(rdp));
-	pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s%s\n",
+	pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%lu/%lu fqs=%ld %s%s\n",
 	       cpu,
 	       "O."[!!cpu_online(cpu)],
 	       "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
@@ -510,7 +510,7 @@ 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,
 		       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


  parent reply	other threads:[~2021-09-15 17:59 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-10  8:53 /proc/stat interrupt counter wrap-around Alexei Lozovsky
2021-09-11  3:48 ` [PATCH 0/7] proc/stat: Maintain monotonicity of "intr" and "softirq" Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 1/7] genirq: Use unsigned int for irqs_sum Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 2/7] powerpc/irq: arch_irq_stat_cpu() returns unsigned int Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 3/7] x86/irq: " Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 4/7] x86/irq: arch_irq_stat() " Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 5/7] proc/stat: Use unsigned int for "intr" sum Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 6/7] proc/stat: Use unsigned int for "softirq" sum Alexei Lozovsky
2021-09-11  3:48   ` [PATCH 7/7] docs: proc.rst: stat: Note the interrupt counter wrap-around Alexei Lozovsky
2021-09-11  3:59     ` Randy Dunlap
2021-09-12  9:30   ` [PATCH 0/7] proc/stat: Maintain monotonicity of "intr" and "softirq" Alexey Dobriyan
2021-09-12 12:37     ` Alexei Lozovsky
2021-09-14 14:11       ` Thomas Gleixner
2021-09-15  4:24         ` Alexei Lozovsky
2021-09-15 17:58   ` [PATCH v2 00/12] " Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 01/12] genirq: Use READ_ONCE for IRQ counter reads Alexei Lozovsky
2021-09-15 17:58     ` Alexei Lozovsky [this message]
2021-09-15 17:58     ` [PATCH v2 03/12] powerpc/irq: " Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 04/12] powerpc/irq: Use unsigned long for IRQ counters Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 05/12] powerpc/irq: Use unsigned long for IRQ counter sum Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 06/12] x86/irq: Use READ_ONCE for IRQ counter reads Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 07/12] x86/irq: Use unsigned long for IRQ counters Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 08/12] x86/irq: Use unsigned long for IRQ counters more Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 09/12] x86/irq: Use unsigned long for IRQ counter sum Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 10/12] proc/stat: Use unsigned long for "intr" sum Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 11/12] proc/stat: Use unsigned long for "softirq" sum Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 12/12] docs: proc.rst: stat: Note the interrupt counter wrap-around Alexei Lozovsky

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