From: Mark Rutland <mark.rutland@arm.com> To: Pingfan Liu <kernelfans@gmail.com> Cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>, Joey Gouly <joey.gouly@arm.com>, Sami Tolvanen <samitolvanen@google.com>, Julien Thierry <julien.thierry@arm.com>, Yuichi Ito <ito-yuichi@fujitsu.com>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCHv2 3/5] kernel/irq: make irq_{enter,exit}() in handle_domain_irq() arch optional Date: Tue, 28 Sep 2021 09:55:00 +0100 [thread overview] Message-ID: <20210928085500.GC1924@C02TD0UTHF1T.local> (raw) In-Reply-To: <20210924132837.45994-4-kernelfans@gmail.com> On Fri, Sep 24, 2021 at 09:28:35PM +0800, Pingfan Liu wrote: > handle_domain_irq() contains two major parts: > -1. irq_enter()/irq_exit(), which serves as hooks for rcu and trace etc. > -2. irq mapping and dispatching > > After the introduction of irqentry_enter()/irqentry_exit() and arch > specific counterpart (e.g. arm64), roughly speaking, rcu_irq_enter() has > already been called. Hence here comes requirement to move > irq_enter/irq_exit out of handle_domain_irq(). And arches should handle > about irq_enter_rcu()/irq_exit_rcu() by themself. > > Since there is still arches, which does not adopt irqentry_enter(), let > irq_enter()/irq_exit() arch optional in handle_domain_irq(). The patch below looks good to me, but the commit message is a little hard to follow. How about: When an IRQ is taken, some accounting needs to be performed to enter and exit IRQ context around the IRQ handler. Historically arch code would leave this to the irqchip or core IRQ code, but these days we want this to happen in exception entry code, and architectures such as arm64 do this. Currently handle_domain_irq() performs this entry/exit accounting, and if used on an architecture where the entry code also does this, the entry/exit accounting will be performed twice per IRQ. This is problematic as core RCU code such as rcu_is_cpu_rrupt_from_idle() depends on this happening once per IRQ, and will not detect quescent periods correctly, leading to stall warnings. As irqchip drivers which use handle_domain_irq() need to work on architectures with or without their own entry/exit accounting, this patch makes handle_domain_irq() conditionally perform the entry accounting depending on a new HAVE_ARCH_IRQENTRY Kconfig symbol that architectures can select if they perform this entry accounting themselves. For architectures which do not select the symbol. there should be no functional change as a result of this patch. With that commit message: Reviewed-by: Mark Rutland <mark.rutland@arm.com> Mark. > Signed-off-by: Pingfan Liu <kernelfans@gmail.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Marc Zyngier <maz@kernel.org> > Cc: Joey Gouly <joey.gouly@arm.com> > Cc: Sami Tolvanen <samitolvanen@google.com> > Cc: Julien Thierry <julien.thierry@arm.com> > Cc: Yuichi Ito <ito-yuichi@fujitsu.com> > Cc: linux-arm-kernel@lists.infradead.org > To: linux-kernel@vger.kernel.org > --- > kernel/irq/Kconfig | 3 +++ > kernel/irq/irqdesc.c | 4 ++++ > 2 files changed, 7 insertions(+) > > diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig > index fbc54c2a7f23..defa1db2d664 100644 > --- a/kernel/irq/Kconfig > +++ b/kernel/irq/Kconfig > @@ -100,6 +100,9 @@ config IRQ_MSI_IOMMU > config HANDLE_DOMAIN_IRQ > bool > > +config HAVE_ARCH_IRQENTRY > + bool > + > config IRQ_TIMINGS > bool > > diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c > index 4e3c29bb603c..fd5dd9d278b5 100644 > --- a/kernel/irq/irqdesc.c > +++ b/kernel/irq/irqdesc.c > @@ -693,7 +693,9 @@ int handle_domain_irq(struct irq_domain *domain, > struct irq_desc *desc; > int ret = 0; > > +#ifndef CONFIG_HAVE_ARCH_IRQENTRY > irq_enter(); > +#endif > > /* The irqdomain code provides boundary checks */ > desc = irq_resolve_mapping(domain, hwirq); > @@ -702,7 +704,9 @@ int handle_domain_irq(struct irq_domain *domain, > else > ret = -EINVAL; > > +#ifndef CONFIG_HAVE_ARCH_IRQENTRY > irq_exit(); > +#endif > set_irq_regs(old_regs); > return ret; > } > -- > 2.31.1 >
WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com> To: Pingfan Liu <kernelfans@gmail.com> Cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>, Joey Gouly <joey.gouly@arm.com>, Sami Tolvanen <samitolvanen@google.com>, Julien Thierry <julien.thierry@arm.com>, Yuichi Ito <ito-yuichi@fujitsu.com>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCHv2 3/5] kernel/irq: make irq_{enter,exit}() in handle_domain_irq() arch optional Date: Tue, 28 Sep 2021 09:55:00 +0100 [thread overview] Message-ID: <20210928085500.GC1924@C02TD0UTHF1T.local> (raw) In-Reply-To: <20210924132837.45994-4-kernelfans@gmail.com> On Fri, Sep 24, 2021 at 09:28:35PM +0800, Pingfan Liu wrote: > handle_domain_irq() contains two major parts: > -1. irq_enter()/irq_exit(), which serves as hooks for rcu and trace etc. > -2. irq mapping and dispatching > > After the introduction of irqentry_enter()/irqentry_exit() and arch > specific counterpart (e.g. arm64), roughly speaking, rcu_irq_enter() has > already been called. Hence here comes requirement to move > irq_enter/irq_exit out of handle_domain_irq(). And arches should handle > about irq_enter_rcu()/irq_exit_rcu() by themself. > > Since there is still arches, which does not adopt irqentry_enter(), let > irq_enter()/irq_exit() arch optional in handle_domain_irq(). The patch below looks good to me, but the commit message is a little hard to follow. How about: When an IRQ is taken, some accounting needs to be performed to enter and exit IRQ context around the IRQ handler. Historically arch code would leave this to the irqchip or core IRQ code, but these days we want this to happen in exception entry code, and architectures such as arm64 do this. Currently handle_domain_irq() performs this entry/exit accounting, and if used on an architecture where the entry code also does this, the entry/exit accounting will be performed twice per IRQ. This is problematic as core RCU code such as rcu_is_cpu_rrupt_from_idle() depends on this happening once per IRQ, and will not detect quescent periods correctly, leading to stall warnings. As irqchip drivers which use handle_domain_irq() need to work on architectures with or without their own entry/exit accounting, this patch makes handle_domain_irq() conditionally perform the entry accounting depending on a new HAVE_ARCH_IRQENTRY Kconfig symbol that architectures can select if they perform this entry accounting themselves. For architectures which do not select the symbol. there should be no functional change as a result of this patch. With that commit message: Reviewed-by: Mark Rutland <mark.rutland@arm.com> Mark. > Signed-off-by: Pingfan Liu <kernelfans@gmail.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Marc Zyngier <maz@kernel.org> > Cc: Joey Gouly <joey.gouly@arm.com> > Cc: Sami Tolvanen <samitolvanen@google.com> > Cc: Julien Thierry <julien.thierry@arm.com> > Cc: Yuichi Ito <ito-yuichi@fujitsu.com> > Cc: linux-arm-kernel@lists.infradead.org > To: linux-kernel@vger.kernel.org > --- > kernel/irq/Kconfig | 3 +++ > kernel/irq/irqdesc.c | 4 ++++ > 2 files changed, 7 insertions(+) > > diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig > index fbc54c2a7f23..defa1db2d664 100644 > --- a/kernel/irq/Kconfig > +++ b/kernel/irq/Kconfig > @@ -100,6 +100,9 @@ config IRQ_MSI_IOMMU > config HANDLE_DOMAIN_IRQ > bool > > +config HAVE_ARCH_IRQENTRY > + bool > + > config IRQ_TIMINGS > bool > > diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c > index 4e3c29bb603c..fd5dd9d278b5 100644 > --- a/kernel/irq/irqdesc.c > +++ b/kernel/irq/irqdesc.c > @@ -693,7 +693,9 @@ int handle_domain_irq(struct irq_domain *domain, > struct irq_desc *desc; > int ret = 0; > > +#ifndef CONFIG_HAVE_ARCH_IRQENTRY > irq_enter(); > +#endif > > /* The irqdomain code provides boundary checks */ > desc = irq_resolve_mapping(domain, hwirq); > @@ -702,7 +704,9 @@ int handle_domain_irq(struct irq_domain *domain, > else > ret = -EINVAL; > > +#ifndef CONFIG_HAVE_ARCH_IRQENTRY > irq_exit(); > +#endif > set_irq_regs(old_regs); > return ret; > } > -- > 2.31.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-09-28 8:55 UTC|newest] Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-24 13:28 [PATCHv2 0/5] arm64/irqentry: remove duplicate housekeeping of Pingfan Liu 2021-09-24 13:28 ` Pingfan Liu 2021-09-24 13:28 ` [PATCHv2 1/5] arm64/entry-common: push the judgement of nmi ahead Pingfan Liu 2021-09-24 13:28 ` Pingfan Liu 2021-09-24 17:53 ` Mark Rutland 2021-09-24 17:53 ` Mark Rutland 2021-09-25 15:39 ` Pingfan Liu 2021-09-25 15:39 ` Pingfan Liu 2021-09-30 13:32 ` Mark Rutland 2021-09-30 13:32 ` Mark Rutland 2021-10-08 4:01 ` Pingfan Liu 2021-10-08 4:01 ` Pingfan Liu 2021-10-08 14:55 ` Pingfan Liu 2021-10-08 14:55 ` Pingfan Liu 2021-10-08 17:25 ` Mark Rutland 2021-10-08 17:25 ` Mark Rutland 2021-10-09 3:49 ` Pingfan Liu 2021-10-09 3:49 ` Pingfan Liu 2021-10-08 15:45 ` Paul E. McKenney 2021-10-08 15:45 ` Paul E. McKenney 2021-10-09 4:14 ` Pingfan Liu 2021-10-09 4:14 ` Pingfan Liu 2021-09-24 13:28 ` [PATCHv2 2/5] irqchip/GICv3: expose handle_nmi() directly Pingfan Liu 2021-09-24 13:28 ` Pingfan Liu 2021-09-24 13:28 ` [PATCHv2 3/5] kernel/irq: make irq_{enter,exit}() in handle_domain_irq() arch optional Pingfan Liu 2021-09-24 13:28 ` [PATCHv2 3/5] kernel/irq: make irq_{enter, exit}() " Pingfan Liu 2021-09-28 8:55 ` Mark Rutland [this message] 2021-09-28 8:55 ` [PATCHv2 3/5] kernel/irq: make irq_{enter,exit}() " Mark Rutland 2021-09-29 3:15 ` Pingfan Liu 2021-09-29 3:15 ` Pingfan Liu 2021-09-24 13:28 ` [PATCHv2 4/5] irqchip/GICv3: let gic_handle_irq() utilize irqentry on arm64 Pingfan Liu 2021-09-24 13:28 ` Pingfan Liu 2021-09-28 9:10 ` Mark Rutland 2021-09-28 9:10 ` Mark Rutland 2021-09-29 3:10 ` Pingfan Liu 2021-09-29 3:10 ` Pingfan Liu 2021-09-29 7:20 ` Marc Zyngier 2021-09-29 7:20 ` Marc Zyngier 2021-09-29 8:27 ` Pingfan Liu 2021-09-29 8:27 ` Pingfan Liu 2021-09-29 9:23 ` Mark Rutland 2021-09-29 9:23 ` Mark Rutland 2021-09-29 11:40 ` Pingfan Liu 2021-09-29 11:40 ` Pingfan Liu 2021-09-29 14:29 ` Pingfan Liu 2021-09-29 14:29 ` Pingfan Liu 2021-09-29 17:41 ` Mark Rutland 2021-09-29 17:41 ` Mark Rutland 2021-09-24 13:28 ` [PATCHv2 5/5] irqchip/GICv3: make reschedule-ipi light weight Pingfan Liu 2021-09-24 13:28 ` Pingfan Liu 2021-09-29 7:24 ` Marc Zyngier 2021-09-29 7:24 ` Marc Zyngier 2021-09-29 8:32 ` Pingfan Liu 2021-09-29 8:32 ` Pingfan Liu 2021-09-24 17:36 ` [PATCHv2 0/5] arm64/irqentry: remove duplicate housekeeping of Mark Rutland 2021-09-24 17:36 ` Mark Rutland 2021-09-24 22:59 ` Paul E. McKenney 2021-09-24 22:59 ` Paul E. McKenney 2021-09-27 9:23 ` Mark Rutland 2021-09-27 9:23 ` Mark Rutland 2021-09-28 0:09 ` Paul E. McKenney 2021-09-28 0:09 ` Paul E. McKenney 2021-09-28 8:32 ` Mark Rutland 2021-09-28 8:32 ` Mark Rutland 2021-09-28 8:35 ` Mark Rutland 2021-09-28 8:35 ` Mark Rutland 2021-09-28 9:52 ` Sven Schnelle 2021-09-28 9:52 ` Sven Schnelle 2021-09-28 10:26 ` Mark Rutland 2021-09-28 10:26 ` Mark Rutland 2021-09-28 13:55 ` Paul E. McKenney 2021-09-28 13:55 ` Paul E. McKenney 2021-09-25 15:12 ` Pingfan Liu 2021-09-25 15:12 ` Pingfan Liu
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20210928085500.GC1924@C02TD0UTHF1T.local \ --to=mark.rutland@arm.com \ --cc=catalin.marinas@arm.com \ --cc=ito-yuichi@fujitsu.com \ --cc=joey.gouly@arm.com \ --cc=julien.thierry@arm.com \ --cc=kernelfans@gmail.com \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=maz@kernel.org \ --cc=samitolvanen@google.com \ --cc=tglx@linutronix.de \ --cc=will@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.