From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A371C2D63E8 for ; Sun, 17 May 2026 20:02:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779048142; cv=none; b=NvihOWRHrC0ws6h92z0nMMa0/x2ixgUwYpFe0J90tewdob4rJowFJZZb7rPPS296PH/JtSLt6yHwlnUCcfxGatWE/gqUU5zZmcDrk/X/9qMp+pFIEME5GumyUA6FFTQdzXQzSJUZHlvOutrun5CHeK3t/JQFW6Fd5JJx9fOyh5c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779048142; c=relaxed/simple; bh=wkvY4dCjtpJYVP6zd1sQmkIF8zFLd5TpaMmdE6Hl+sI=; h=Date:Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=MxyR+j95c2yS3l1oXarryh4J9rrmckF6kSn2ADk5SVuvf+ZsorEry2/0HmEGPSABQ+/TPWiWq6JakoofgDYuyu6KbeW67L5J989Ippb66Ae7oZS5DI8zH9yXYHxcT20Q1yLxUscJ/ixMVELdSkYvS6HBGeSLSDOZfZNbauoYLBk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WxVO545v; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WxVO545v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8E61C2BCB0; Sun, 17 May 2026 20:02:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1779048142; bh=wkvY4dCjtpJYVP6zd1sQmkIF8zFLd5TpaMmdE6Hl+sI=; h=Date:From:To:Cc:Subject:References:From; b=WxVO545vlFOFAh/VD4yRKsqn3KS3y4sHKfPF0xjqJn2zKaT2Hrj0O1rN0/jOi95Es TF3heWpjw2ctzheXsmdcE+1ZCGKPPRs2xjlgKYwwUmuIjHFvhBjAML6C8Wmrd7Ap6i WTedeKulAIigwErg3xfP2InTt5asoO52WPQ+/NtonMiLrYQyfKvtl6HRrgq34MsFJS j8kEqOsYSSMbaGZXlyyCY9e96iLa5lmVrnmydPiUHRTNTn3s+sWfjkPUCwfSniFeI6 TlhBX6qin7xd5UHpHenWRhXNtPxR8jL0lFTHhjHGwJTYW2CFqZIpCWiYlhebGXT6h8 m+gKvIznZwO0Q== Date: Sun, 17 May 2026 22:02:19 +0200 Message-ID: <20260517194931.680943749@kernel.org> User-Agent: quilt/0.68 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Michael Kelley , Dmitry Ilvokhin , Radu Rendec , Jan Kiszka , Kieran Bingham , Florian Fainelli , Marc Zyngier Subject: [patch V6 10/16] genirq: Cache the condition for /proc/interrupts exposure References: <20260517194421.705253664@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Thomas Gleixner show_interrupts() evaluates a boatload of conditions to establish whether it should expose an interrupt in /proc/interrupts or not. That can be simplified by caching the condition in an internal status flag, which is updated when one of the relevant inputs changes. The irq_desc::kstat_irq check is dropped because visible interrupt descriptors always have a valid pointer. As a result the number of instructions and branches for reading /proc/interrupts is reduced significantly. Signed-off-by: Thomas Gleixner Tested-by: Michael Kelley Reviewed-by: Dmitry Ilvokhin Reviewed-by: Radu Rendec --- V4: Cover freeing of per CPU and NMI type interrupts V3: Remove the historical kstat_irq check - Radu V2: s/IRQF_/IRQ/ and fixup the enum treatment - Dmitry --- include/linux/irq.h | 1 + kernel/irq/chip.c | 2 ++ kernel/irq/internals.h | 2 ++ kernel/irq/manage.c | 8 +++++++- kernel/irq/proc.c | 15 +++++++++++---- kernel/irq/settings.h | 13 +++++++++++++ 6 files changed, 36 insertions(+), 5 deletions(-) --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -103,6 +103,7 @@ enum { IRQ_DISABLE_UNLAZY = (1 << 19), IRQ_HIDDEN = (1 << 20), IRQ_NO_DEBUG = (1 << 21), + IRQ_RESERVED = (1 << 22), }; #define IRQF_MODIFY_MASK \ --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -1007,6 +1007,7 @@ static void WARN_ON(irq_chip_pm_get(irq_desc_get_irq_data(desc))); irq_activate_and_startup(desc, IRQ_RESEND); } + irq_proc_update_valid(desc); } void __irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained, @@ -1067,6 +1068,7 @@ void irq_modify_status(unsigned int irq, trigger = tmp; irqd_set(&desc->irq_data, trigger); + irq_proc_update_valid(desc); } } EXPORT_SYMBOL_GPL(irq_modify_status); --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -123,6 +123,7 @@ extern void register_irq_proc(unsigned i extern void unregister_irq_proc(unsigned int irq, struct irq_desc *desc); extern void register_handler_proc(unsigned int irq, struct irqaction *action); extern void unregister_handler_proc(unsigned int irq, struct irqaction *action); +void irq_proc_update_valid(struct irq_desc *desc); #else static inline void register_irq_proc(unsigned int irq, struct irq_desc *desc) { } static inline void unregister_irq_proc(unsigned int irq, struct irq_desc *desc) { } @@ -130,6 +131,7 @@ static inline void register_handler_proc struct irqaction *action) { } static inline void unregister_handler_proc(unsigned int irq, struct irqaction *action) { } +static inline void irq_proc_update_valid(struct irq_desc *desc) { } #endif extern bool irq_can_set_affinity_usr(unsigned int irq); --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1802,6 +1802,7 @@ static int __enable_irq(desc); } + irq_proc_update_valid(desc); raw_spin_unlock_irqrestore(&desc->lock, flags); chip_bus_sync_unlock(desc); mutex_unlock(&desc->request_mutex); @@ -1906,6 +1907,7 @@ static struct irqaction *__free_irq(stru desc->affinity_hint = NULL; #endif + irq_proc_update_valid(desc); raw_spin_unlock_irqrestore(&desc->lock, flags); /* * Drop bus_lock here so the changes which were done in the chip @@ -2047,6 +2049,8 @@ static const void *__cleanup_nmi(unsigne irq_shutdown_and_deactivate(desc); } + irq_proc_update_valid(desc); + if (action) unregister_handler_proc(irq, action); kfree(action); @@ -2433,8 +2437,10 @@ static struct irqaction *__free_percpu_i *action_ptr = action->next; /* Demote from NMI if we killed the last action */ - if (!desc->action) + if (!desc->action) { desc->istate &= ~IRQS_NMI; + irq_proc_update_valid(desc); + } } unregister_handler_proc(irq, action); --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -439,6 +439,16 @@ void init_irq_proc(void) register_irq_proc(irq, desc); } +void irq_proc_update_valid(struct irq_desc *desc) +{ + u32 set = _IRQ_PROC_VALID; + + if (irq_settings_is_hidden(desc) || irq_desc_is_chained(desc) || !desc->action) + set = 0; + + irq_settings_update_proc_valid(desc, set); +} + #ifdef CONFIG_GENERIC_IRQ_SHOW int __weak arch_show_interrupts(struct seq_file *p, int prec) @@ -515,10 +525,7 @@ int show_interrupts(struct seq_file *p, guard(rcu)(); desc = irq_to_desc(i); - if (!desc || irq_settings_is_hidden(desc)) - return 0; - - if (!desc->action || irq_desc_is_chained(desc) || !desc->kstat_irqs) + if (!desc || !irq_settings_proc_valid(desc)) return 0; seq_printf(p, "%*d:", prec, i); --- a/kernel/irq/settings.h +++ b/kernel/irq/settings.h @@ -18,6 +18,7 @@ enum { _IRQ_DISABLE_UNLAZY = IRQ_DISABLE_UNLAZY, _IRQ_HIDDEN = IRQ_HIDDEN, _IRQ_NO_DEBUG = IRQ_NO_DEBUG, + _IRQ_PROC_VALID = IRQ_RESERVED, _IRQF_MODIFY_MASK = IRQF_MODIFY_MASK, }; @@ -34,6 +35,7 @@ enum { #define IRQ_DISABLE_UNLAZY GOT_YOU_MORON #define IRQ_HIDDEN GOT_YOU_MORON #define IRQ_NO_DEBUG GOT_YOU_MORON +#define IRQ_RESERVED GOT_YOU_MORON #undef IRQF_MODIFY_MASK #define IRQF_MODIFY_MASK GOT_YOU_MORON @@ -180,3 +182,14 @@ static inline bool irq_settings_no_debug { return desc->status_use_accessors & _IRQ_NO_DEBUG; } + +static inline bool irq_settings_proc_valid(struct irq_desc *desc) +{ + return desc->status_use_accessors & _IRQ_PROC_VALID; +} + +static inline void irq_settings_update_proc_valid(struct irq_desc *desc, u32 set) +{ + desc->status_use_accessors &= ~_IRQ_PROC_VALID; + desc->status_use_accessors |= (set & _IRQ_PROC_VALID); +}