From 4ace6139bf23ab4f152ba4207fc10b76cc01d2a5 Mon Sep 17 00:00:00 2001 From: Alex Smith Date: Fri, 24 Jul 2015 16:57:49 +0100 Subject: [PATCH] MIPS: SMP: Don't increment irq_count multiple times for call function IPIs The majority of SMP platforms handle their IPIs through do_IRQ() which calls irq_{enter/exit}(). When a call function IPI is received, smp_call_function_interrupt() is called which also calls irq_{enter,exit}(), meaning irq_count is raised twice. When tick broadcasting is used (which is implemented via a call function IPI), this incorrectly causes all CPU idle time on the core receiving broadcast ticks to be accounted as time spent servicing IRQs, as account_process_tick() will account as such if irq_count is greater than 1. This results in 100% CPU usage being reported on a core which receives its ticks via broadcast. This patch removes the SMP smp_call_function_interrupt() wrapper which calls irq_{enter,exit}(). Platforms which handle their IPIs through do_IRQ() now call generic_smp_call_function_interrupt() directly to avoid incrementing irq_count a second time. Platforms which don't (loongson, sgi-ip27, sibyte) call generic_smp_call_function_interrupt() wrapped in irq_{enter,exit}(). Signed-off-by: Alex Smith Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/10770/ Signed-off-by: Ralf Baechle --- arch/mips/cavium-octeon/smp.c | 2 +- arch/mips/include/asm/smp.h | 2 -- arch/mips/kernel/smp-bmips.c | 4 ++-- arch/mips/kernel/smp.c | 10 ---------- arch/mips/lantiq/irq.c | 2 +- arch/mips/loongson64/loongson-3/smp.c | 7 +++++-- arch/mips/mti-malta/malta-int.c | 2 +- arch/mips/netlogic/common/smp.c | 2 +- arch/mips/paravirt/paravirt-smp.c | 2 +- arch/mips/pmcs-msp71xx/msp_smp.c | 2 +- arch/mips/sgi-ip27/ip27-irq.c | 8 ++++++-- arch/mips/sibyte/bcm1480/smp.c | 9 +++++---- arch/mips/sibyte/sb1250/smp.c | 7 +++++-- drivers/irqchip/irq-mips-gic.c | 2 +- 14 files changed, 30 insertions(+), 31 deletions(-) diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c index 56f5d080ef9d..b7fa9ae28c36 100644 --- a/arch/mips/cavium-octeon/smp.c +++ b/arch/mips/cavium-octeon/smp.c @@ -42,7 +42,7 @@ static irqreturn_t mailbox_interrupt(int irq, void *dev_id) cvmx_write_csr(CVMX_CIU_MBOX_CLRX(coreid), action); if (action & SMP_CALL_FUNCTION) - smp_call_function_interrupt(); + generic_smp_call_function_interrupt(); if (action & SMP_RESCHEDULE_YOURSELF) scheduler_ipi(); diff --git a/arch/mips/include/asm/smp.h b/arch/mips/include/asm/smp.h index 16f1ea9ab191..03722d4326a1 100644 --- a/arch/mips/include/asm/smp.h +++ b/arch/mips/include/asm/smp.h @@ -83,8 +83,6 @@ static inline void __cpu_die(unsigned int cpu) extern void play_dead(void); #endif -extern asmlinkage void smp_call_function_interrupt(void); - static inline void arch_send_call_function_single_ipi(int cpu) { extern struct plat_smp_ops *mp_ops; /* private */ diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c index 336708ae5c5b..78cf8c2f1de0 100644 --- a/arch/mips/kernel/smp-bmips.c +++ b/arch/mips/kernel/smp-bmips.c @@ -284,7 +284,7 @@ static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id) if (action == 0) scheduler_ipi(); else - smp_call_function_interrupt(); + generic_smp_call_function_interrupt(); return IRQ_HANDLED; } @@ -336,7 +336,7 @@ static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id) if (action & SMP_RESCHEDULE_YOURSELF) scheduler_ipi(); if (action & SMP_CALL_FUNCTION) - smp_call_function_interrupt(); + generic_smp_call_function_interrupt(); return IRQ_HANDLED; } diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c index d0744cc77ea7..a31896c33716 100644 --- a/arch/mips/kernel/smp.c +++ b/arch/mips/kernel/smp.c @@ -192,16 +192,6 @@ asmlinkage void start_secondary(void) cpu_startup_entry(CPUHP_ONLINE); } -/* - * Call into both interrupt handlers, as we share the IPI for them - */ -void __irq_entry smp_call_function_interrupt(void) -{ - irq_enter(); - generic_smp_call_function_interrupt(); - irq_exit(); -} - static void stop_this_cpu(void *dummy) { /* diff --git a/arch/mips/lantiq/irq.c b/arch/mips/lantiq/irq.c index 6ab10573490d..be18648cb8c8 100644 --- a/arch/mips/lantiq/irq.c +++ b/arch/mips/lantiq/irq.c @@ -293,7 +293,7 @@ static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id) static irqreturn_t ipi_call_interrupt(int irq, void *dev_id) { - smp_call_function_interrupt(); + generic_smp_call_function_interrupt(); return IRQ_HANDLED; } diff --git a/arch/mips/loongson64/loongson-3/smp.c b/arch/mips/loongson64/loongson-3/smp.c index 509877c6e9d9..1a4738a8f2d3 100644 --- a/arch/mips/loongson64/loongson-3/smp.c +++ b/arch/mips/loongson64/loongson-3/smp.c @@ -266,8 +266,11 @@ void loongson3_ipi_interrupt(struct pt_regs *regs) if (action & SMP_RESCHEDULE_YOURSELF) scheduler_ipi(); - if (action & SMP_CALL_FUNCTION) - smp_call_function_interrupt(); + if (action & SMP_CALL_FUNCTION) { + irq_enter(); + generic_smp_call_function_interrupt(); + irq_exit(); + } if (action & SMP_ASK_C0COUNT) { BUG_ON(cpu != 0); diff --git a/arch/mips/mti-malta/malta-int.c b/arch/mips/mti-malta/malta-int.c index d1392f8f5811..fa8f591f3713 100644 --- a/arch/mips/mti-malta/malta-int.c +++ b/arch/mips/mti-malta/malta-int.c @@ -222,7 +222,7 @@ static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id) static irqreturn_t ipi_call_interrupt(int irq, void *dev_id) { - smp_call_function_interrupt(); + generic_smp_call_function_interrupt(); return IRQ_HANDLED; } diff --git a/arch/mips/netlogic/common/smp.c b/arch/mips/netlogic/common/smp.c index dc3e327fbbac..f5fff228b347 100644 --- a/arch/mips/netlogic/common/smp.c +++ b/arch/mips/netlogic/common/smp.c @@ -86,7 +86,7 @@ void nlm_smp_function_ipi_handler(unsigned int irq, struct irq_desc *desc) { clear_c0_eimr(irq); ack_c0_eirr(irq); - smp_call_function_interrupt(); + generic_smp_call_function_interrupt(); set_c0_eimr(irq); } diff --git a/arch/mips/paravirt/paravirt-smp.c b/arch/mips/paravirt/paravirt-smp.c index 42181c7105df..f8d3e081b2eb 100644 --- a/arch/mips/paravirt/paravirt-smp.c +++ b/arch/mips/paravirt/paravirt-smp.c @@ -114,7 +114,7 @@ static irqreturn_t paravirt_reched_interrupt(int irq, void *dev_id) static irqreturn_t paravirt_function_interrupt(int irq, void *dev_id) { - smp_call_function_interrupt(); + generic_smp_call_function_interrupt(); return IRQ_HANDLED; } diff --git a/arch/mips/pmcs-msp71xx/msp_smp.c b/arch/mips/pmcs-msp71xx/msp_smp.c index 10170580a2de..ffa0f7101a97 100644 --- a/arch/mips/pmcs-msp71xx/msp_smp.c +++ b/arch/mips/pmcs-msp71xx/msp_smp.c @@ -44,7 +44,7 @@ static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id) static irqreturn_t ipi_call_interrupt(int irq, void *dev_id) { - smp_call_function_interrupt(); + generic_smp_call_function_interrupt(); return IRQ_HANDLED; } diff --git a/arch/mips/sgi-ip27/ip27-irq.c b/arch/mips/sgi-ip27/ip27-irq.c index 3fbaef97a1b8..16ec4e12daa3 100644 --- a/arch/mips/sgi-ip27/ip27-irq.c +++ b/arch/mips/sgi-ip27/ip27-irq.c @@ -107,10 +107,14 @@ static void ip27_do_irq_mask0(void) scheduler_ipi(); } else if (pend0 & (1UL << CPU_CALL_A_IRQ)) { LOCAL_HUB_CLR_INTR(CPU_CALL_A_IRQ); - smp_call_function_interrupt(); + irq_enter(); + generic_smp_call_function_interrupt(); + irq_exit(); } else if (pend0 & (1UL << CPU_CALL_B_IRQ)) { LOCAL_HUB_CLR_INTR(CPU_CALL_B_IRQ); - smp_call_function_interrupt(); + irq_enter(); + generic_smp_call_function_interrupt(); + irq_exit(); } else #endif { diff --git a/arch/mips/sibyte/bcm1480/smp.c b/arch/mips/sibyte/bcm1480/smp.c index af7d44edd9a8..4c71aea25663 100644 --- a/arch/mips/sibyte/bcm1480/smp.c +++ b/arch/mips/sibyte/bcm1480/smp.c @@ -29,8 +29,6 @@ #include #include -extern void smp_call_function_interrupt(void); - /* * These are routines for dealing with the bcm1480 smp capabilities * independent of board/firmware @@ -184,6 +182,9 @@ void bcm1480_mailbox_interrupt(void) if (action & SMP_RESCHEDULE_YOURSELF) scheduler_ipi(); - if (action & SMP_CALL_FUNCTION) - smp_call_function_interrupt(); + if (action & SMP_CALL_FUNCTION) { + irq_enter(); + generic_smp_call_function_interrupt(); + irq_exit(); + } } diff --git a/arch/mips/sibyte/sb1250/smp.c b/arch/mips/sibyte/sb1250/smp.c index c0c4b3f88a08..1cf66f5ff23d 100644 --- a/arch/mips/sibyte/sb1250/smp.c +++ b/arch/mips/sibyte/sb1250/smp.c @@ -172,6 +172,9 @@ void sb1250_mailbox_interrupt(void) if (action & SMP_RESCHEDULE_YOURSELF) scheduler_ipi(); - if (action & SMP_CALL_FUNCTION) - smp_call_function_interrupt(); + if (action & SMP_CALL_FUNCTION) { + irq_enter(); + generic_smp_call_function_interrupt(); + irq_exit(); + } } diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c index b7d54d428b5e..ff4be0515a0d 100644 --- a/drivers/irqchip/irq-mips-gic.c +++ b/drivers/irqchip/irq-mips-gic.c @@ -538,7 +538,7 @@ static irqreturn_t ipi_resched_interrupt(int irq, void *dev_id) static irqreturn_t ipi_call_interrupt(int irq, void *dev_id) { - smp_call_function_interrupt(); + generic_smp_call_function_interrupt(); return IRQ_HANDLED; }