From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vineet.Gupta1@synopsys.com (Vineet Gupta) Date: Fri, 11 Dec 2015 16:49:11 +0530 Subject: [PATCH 1/3] ARCv2: intc: Fix random perf irq disabling in SMP setup In-Reply-To: <1449832753-6767-1-git-send-email-vgupta@synopsys.com> References: <1449832753-6767-1-git-send-email-vgupta@synopsys.com> List-ID: Message-ID: <1449832753-6767-2-git-send-email-vgupta@synopsys.com> To: linux-snps-arc@lists.infradead.org As part of fixing another perf issue, observed that after a perf run, the interrupt got disabled on one/more cores. | [ARCLinux]# cat /proc/interrupts | grep perf | 20: 0 0 0 0 ARCv2 core Intc 20 ARC perf counters | | [ARCLinux]# perf record -c 20000 /sbin/hackbench | Running with 10*40 (== 400) tasks. | | [ARCLinux]# cat /proc/interrupts | grep perf | 20: 0 522 8 51916 ARCv2 core Intc 20 ARC perf counters | | [ARCLinux]# perf record -c 20000 /sbin/hackbench | Running with 10*40 (== 400) tasks. | | [ARCLinux]# cat /proc/interrupts | grep perf | 20: 0 522 8 104368 ARCv2 core Intc 20 ARC perf counters Turns out that despite requesting perf irq as percpu, the flow handler registered was not handle_percpu_irq() Given that on ARCv2 cores, IRQs < 24 are always private to cpu, we register the right handler at the very onset. Cc: Marc Zyngier Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Alexey Brodkin Cc: stable at vger.kernel.org #4.2+ Cc: linux-kernel at vger.kernel.org Signed-off-by: Vineet Gupta --- arch/arc/kernel/intc-arcv2.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c index 26c156827479..0394f9f61b46 100644 --- a/arch/arc/kernel/intc-arcv2.c +++ b/arch/arc/kernel/intc-arcv2.c @@ -106,10 +106,21 @@ static struct irq_chip arcv2_irq_chip = { static int arcv2_irq_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw) { - if (irq == TIMER0_IRQ || irq == IPI_IRQ) + /* + * core intc IRQs [16, 23]: + * Statically assigned always private-per-core (Timers, WDT, IPI, PCT) + */ + if (hw < 24) { + /* + * A subsequent request_percpu_irq() fails if percpu_devid is + * not set. That in turns sets NOAUTOEN, meaning each core needs + * to call enable_percpu_irq() + */ + irq_set_percpu_devid(irq); irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_percpu_irq); - else + } else { irq_set_chip_and_handler(irq, &arcv2_irq_chip, handle_level_irq); + } return 0; } -- 1.9.1