55 lines
1.7 KiB
Diff
55 lines
1.7 KiB
Diff
From 2a5b12519a1a127f899d6d98799bd42a2fbf5674 Mon Sep 17 00:00:00 2001
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Message-Id: <2a5b12519a1a127f899d6d98799bd42a2fbf5674.1601675152.git.zanussi@kernel.org>
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In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Thu, 20 Dec 2012 18:28:26 +0100
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Subject: [PATCH 186/333] block: Use cpu_chill() for retry loops
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
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Retry loops on RT might loop forever when the modifying side was
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preempted. Steven also observed a live lock when there was a
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concurrent priority boosting going on.
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Use cpu_chill() instead of cpu_relax() to let the system
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make progress.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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block/blk-ioc.c | 5 +++--
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1 file changed, 3 insertions(+), 2 deletions(-)
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diff --git a/block/blk-ioc.c b/block/blk-ioc.c
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index 4c810969c3e2..48089f5bcc11 100644
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--- a/block/blk-ioc.c
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+++ b/block/blk-ioc.c
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@@ -9,6 +9,7 @@
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#include <linux/blkdev.h>
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#include <linux/slab.h>
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#include <linux/sched/task.h>
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+#include <linux/delay.h>
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#include "blk.h"
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@@ -119,7 +120,7 @@ static void ioc_release_fn(struct work_struct *work)
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spin_unlock(q->queue_lock);
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} else {
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spin_unlock_irqrestore(&ioc->lock, flags);
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- cpu_relax();
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+ cpu_chill();
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spin_lock_irqsave_nested(&ioc->lock, flags, 1);
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}
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}
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@@ -203,7 +204,7 @@ void put_io_context_active(struct io_context *ioc)
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spin_unlock(icq->q->queue_lock);
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} else {
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spin_unlock_irqrestore(&ioc->lock, flags);
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- cpu_relax();
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+ cpu_chill();
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goto retry;
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}
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}
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--
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2.17.1
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