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From: "tip-bot2 for Thomas Gleixner" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	x86@kernel.org, linux-kernel@vger.kernel.org, maz@kernel.org
Subject: [tip: irq/core] tasklets: Replace barrier() with cpu_relax() in tasklet_unlock_wait()
Date: Wed, 17 Mar 2021 15:49:00 -0000	[thread overview]
Message-ID: <161599614013.398.5397350064896985635.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210309084241.249343366@linutronix.de>

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     d2da74d1278a1b51ef18beafa9da770f0db1c617
Gitweb:        https://git.kernel.org/tip/d2da74d1278a1b51ef18beafa9da770f0db1c617
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 09 Mar 2021 09:42:04 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 17 Mar 2021 16:33:51 +01:00

tasklets: Replace barrier() with cpu_relax() in tasklet_unlock_wait()

A barrier() in a tight loop which waits for something to happen on a remote
CPU is a pointless exercise. Replace it with cpu_relax() which allows HT
siblings to make progress.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210309084241.249343366@linutronix.de

---
 include/linux/interrupt.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 2b98156..d689fd7 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -672,7 +672,8 @@ static inline void tasklet_unlock(struct tasklet_struct *t)
 
 static inline void tasklet_unlock_wait(struct tasklet_struct *t)
 {
-	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
+	while (test_bit(TASKLET_STATE_RUN, &t->state))
+		cpu_relax();
 }
 #else
 #define tasklet_trylock(t) 1

  reply	other threads:[~2021-03-17 15:50 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-09  8:42 [patch 00/14] tasklets: Replace the spin wait loops and make it RT safe Thomas Gleixner
2021-03-09  8:42 ` [patch 01/14] tasklets: Replace barrier() with cpu_relax() in tasklet_unlock_wait() Thomas Gleixner
2021-03-17 15:49   ` tip-bot2 for Thomas Gleixner [this message]
2021-03-09  8:42 ` [patch 02/14] tasklets: Use static inlines for stub implementations Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Thomas Gleixner
2021-03-09  8:42 ` [patch 03/14] tasklets: Provide tasklet_disable_in_atomic() Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Thomas Gleixner
2021-03-09  8:42 ` [patch 04/14] tasklets: Use spin wait in tasklet_disable() temporarily Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Thomas Gleixner
2021-03-09  8:42 ` [patch 05/14] tasklets: Replace spin wait in tasklet_unlock_wait() Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Peter Zijlstra
2021-03-09  8:42 ` [patch 06/14] tasklets: Replace spin wait in tasklet_kill() Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Peter Zijlstra
2021-03-09  8:42 ` [patch 07/14] tasklets: Prevent tasklet_unlock_spin_wait() deadlock on RT Thomas Gleixner
2021-03-09 15:00   ` Sebastian Andrzej Siewior
2021-03-09 15:21     ` Sebastian Andrzej Siewior
2021-03-10  8:35       ` Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Thomas Gleixner
2021-03-09  8:42 ` [patch 08/14] net: jme: Replace link-change tasklet with work Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Sebastian Andrzej Siewior
2021-03-09  8:42 ` [patch 09/14] net: sundance: Use tasklet_disable_in_atomic() Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Sebastian Andrzej Siewior
2021-03-09  8:42 ` [patch 10/14] ath9k: " Thomas Gleixner
2021-03-09 10:23   ` Kalle Valo
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Sebastian Andrzej Siewior
2021-03-09  8:42 ` [patch 11/14] atm: eni: Use tasklet_disable_in_atomic() in the send() callback Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Sebastian Andrzej Siewior
2021-03-09  8:42 ` [patch 12/14] PCI: hv: Use tasklet_disable_in_atomic() Thomas Gleixner
2021-03-09 22:17   ` Bjorn Helgaas
2021-03-10 11:34   ` Wei Liu
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Sebastian Andrzej Siewior
2021-03-09  8:42 ` [patch 13/14] firewire: ohci: Use tasklet_disable_in_atomic() where required Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Sebastian Andrzej Siewior
2021-03-09  8:42 ` [patch 14/14] tasklets: Switch tasklet_disable() to the sleep wait variant Thomas Gleixner
2021-03-17 15:48   ` [tip: irq/core] " tip-bot2 for Thomas Gleixner
2021-03-09 14:04 ` [patch 00/14] tasklets: Replace the spin wait loops and make it RT safe Peter Zijlstra

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