47 lines
1.2 KiB
Diff
47 lines
1.2 KiB
Diff
Subject: block: Use cpu_chill() for retry loops
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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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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.18/older/patches-4.18.5-rt3.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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--- 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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@@ -118,7 +119,7 @@ static void ioc_release_fn(struct work_s
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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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@@ -202,7 +203,7 @@ void put_io_context_active(struct io_con
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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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