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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 3/7] x86/irq: arch_irq_stat_cpu() returns unsigned int
Date: Sat, 11 Sep 2021 12:48:04 +0900	[thread overview]
Message-ID: <20210911034808.24252-4-me@ilammy.net> (raw)
In-Reply-To: <20210911034808.24252-1-me@ilammy.net>

Like with PowerPC's version, on x86 the interrupt counters that are
added here are all unsigned int too (see irq_cpustat_t for x86)
as well as mce_exception_count and mce_poll_count.

Summing up unsigned int values into u64 does not "handle" overflows,
but if any of the individual counters overflows then the computed
sum is inaccurate.

Signed-off-by: Alexei Lozovsky <me@ilammy.net>
---
 arch/x86/include/asm/hardirq.h | 2 +-
 arch/x86/kernel/irq.c          | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/hardirq.h b/arch/x86/include/asm/hardirq.h
index 275e7fd20310..461536b45391 100644
--- a/arch/x86/include/asm/hardirq.h
+++ b/arch/x86/include/asm/hardirq.h
@@ -54,7 +54,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
 
 extern void ack_bad_irq(unsigned int irq);
 
-extern u64 arch_irq_stat_cpu(unsigned int cpu);
+extern unsigned int arch_irq_stat_cpu(unsigned int cpu);
 #define arch_irq_stat_cpu	arch_irq_stat_cpu
 
 extern u64 arch_irq_stat(void);
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index e28f6a5d14f1..cefe1bc9f42c 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -188,9 +188,9 @@ int arch_show_interrupts(struct seq_file *p, int prec)
 /*
  * /proc/stat helpers
  */
-u64 arch_irq_stat_cpu(unsigned int cpu)
+unsigned int arch_irq_stat_cpu(unsigned int cpu)
 {
-	u64 sum = irq_stats(cpu)->__nmi_count;
+	unsigned int sum = irq_stats(cpu)->__nmi_count;
 
 #ifdef CONFIG_X86_LOCAL_APIC
 	sum += irq_stats(cpu)->apic_timer_irqs;
-- 
2.25.1


  parent reply	other threads:[~2021-09-11  3:48 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   ` Alexei Lozovsky [this message]
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     ` [PATCH v2 02/12] genirq: Use unsigned long for IRQ counters Alexei Lozovsky
2021-09-15 17:58     ` [PATCH v2 03/12] powerpc/irq: Use READ_ONCE for IRQ counter reads 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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