The patch titled
Subject: irq_work: replace wait loop with rcuwait_wait_event
has been added to the -mm mm-nonmm-unstable branch. Its filename is
irq_work-replace-wait-loop-with-rcuwait_wait_event.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/irq_work-replace-wait-loop-with-rcuwait_wait_event.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Steven Davis <goldside000@xxxxxxxxxxx>
Subject: irq_work: replace wait loop with rcuwait_wait_event
Date: Thu, 19 Sep 2024 11:43:26 -0400
The previous implementation of irq_work_sync used a busy-wait loop with
cpu_relax() to check the status of IRQ work. This approach, while
functional, could lead to inefficiencies in CPU usage.
This commit replaces the busy-wait loop with the rcuwait_wait_event
mechanism. This change leverages the RCU wait mechanism to handle waiting
for IRQ work completion more efficiently, improving CPU responsiveness and
reducing unnecessary CPU usage.
Link: https://lkml.kernel.org/r/SJ2P223MB10267BCF19A4A37747A52330F7632@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Steven Davis <goldside000@xxxxxxxxxxx>
Cc: Ankur Arora <ankur.a.arora@xxxxxxxxxx>
Cc: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/irq_work.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/kernel/irq_work.c~irq_work-replace-wait-loop-with-rcuwait_wait_event
+++ a/kernel/irq_work.c
@@ -295,8 +295,7 @@ void irq_work_sync(struct irq_work *work
return;
}
- while (irq_work_is_busy(work))
- cpu_relax();
+ rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work), TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL_GPL(irq_work_sync);
_
Patches currently in -mm which might be from goldside000@xxxxxxxxxxx are
irq_work-replace-wait-loop-with-rcuwait_wait_event.patch
