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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Russell King <linux@armlinux.org.uk>,
	Arnd Bergmann <arnd@arndb.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH 2/2] arm: Disable softirq stacks on PREEMPT_RT.
Date: Mon, 13 Jun 2022 20:24:47 +0200	[thread overview]
Message-ID: <20220613182447.112191-3-bigeasy@linutronix.de> (raw)
In-Reply-To: <20220613182447.112191-1-bigeasy@linutronix.de>

PREEMPT_RT preempts softirqs and the current implementation avoids
do_softirq_own_stack() and only uses __do_softirq().

Disable the unused softirqs stacks on PREEMPT_RT to safe some memory and
ensure that do_softirq_own_stack() is not used which is not expected.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/arm/kernel/irq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kernel/irq.c b/arch/arm/kernel/irq.c
index 5c6f8d11a3ce5..034cb48c9eeb8 100644
--- a/arch/arm/kernel/irq.c
+++ b/arch/arm/kernel/irq.c
@@ -70,6 +70,7 @@ static void __init init_irq_stacks(void)
 	}
 }
 
+#ifndef CONFIG_PREEMPT_RT
 static void ____do_softirq(void *arg)
 {
 	__do_softirq();
@@ -80,7 +81,7 @@ void do_softirq_own_stack(void)
 	call_with_stack(____do_softirq, NULL,
 			__this_cpu_read(irq_stack_ptr));
 }
-
+#endif
 #endif
 
 int arch_show_interrupts(struct seq_file *p, int prec)
-- 
2.36.1


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      parent reply	other threads:[~2022-06-13 18:26 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-13 18:24 [PATCH 0/2] arm: Disable two features which are not compatible with PREEMPT_RT Sebastian Andrzej Siewior
2022-06-13 18:24 ` [PATCH 1/2] arm: Disable jump-label on PREEMPT_RT Sebastian Andrzej Siewior
2022-06-13 18:24 ` Sebastian Andrzej Siewior [this message]

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