47 lines
1.9 KiB
Diff
47 lines
1.9 KiB
Diff
From 0a4ffc921c8c63dbbc2ee27eb7a18549692bf2e4 Mon Sep 17 00:00:00 2001
|
|
Message-Id: <0a4ffc921c8c63dbbc2ee27eb7a18549692bf2e4.1601675153.git.zanussi@kernel.org>
|
|
In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
|
|
References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
|
|
From: Julien Grall <julien.grall@arm.com>
|
|
Date: Wed, 21 Aug 2019 10:24:09 +0100
|
|
Subject: [PATCH 295/333] hrtimer: Prevent using hrtimer_grab_expiry_lock() on
|
|
migration_base
|
|
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
|
|
|
|
[ Upstream commit cef1b87f98823af923a386f3f69149acb212d4a1 ]
|
|
|
|
As tglx puts it:
|
|
|If base == migration_base then there is no point to lock soft_expiry_lock
|
|
|simply because the timer is not executing the callback in soft irq context
|
|
|and the whole lock/unlock dance can be avoided.
|
|
|
|
Furthermore, all the path leading to hrtimer_grab_expiry_lock() assumes
|
|
timer->base and timer->base->cpu_base are always non-NULL. So it is safe
|
|
to remove the NULL checks here.
|
|
|
|
Signed-off-by: Julien Grall <julien.grall@arm.com>
|
|
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908211557420.2223@nanos.tec.linutronix.de
|
|
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
[bigeasy: rewrite changelog]
|
|
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
|
|
---
|
|
kernel/time/hrtimer.c | 2 +-
|
|
1 file changed, 1 insertion(+), 1 deletion(-)
|
|
|
|
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
|
|
index 49d20fe8570f..1a5167c68310 100644
|
|
--- a/kernel/time/hrtimer.c
|
|
+++ b/kernel/time/hrtimer.c
|
|
@@ -943,7 +943,7 @@ void hrtimer_grab_expiry_lock(const struct hrtimer *timer)
|
|
{
|
|
struct hrtimer_clock_base *base = READ_ONCE(timer->base);
|
|
|
|
- if (timer->is_soft && base && base->cpu_base) {
|
|
+ if (timer->is_soft && base != &migration_base) {
|
|
spin_lock(&base->cpu_base->softirq_expiry_lock);
|
|
spin_unlock(&base->cpu_base->softirq_expiry_lock);
|
|
}
|
|
--
|
|
2.17.1
|
|
|