From: Marco Elver <elver@google.com>
Date: Wed, 5 May 2021 01:40:27 +0000 (-0700)
Subject: kfence: use power-efficient work queue to run delayed work
X-Git-Tag: v5.15~1181^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=36f0b35d0894576fe63268ede80d9f5aa140be09;p=platform%2Fkernel%2Flinux-starfive.git

kfence: use power-efficient work queue to run delayed work

Use the power-efficient work queue, to avoid the pathological case where
we keep pinning ourselves on the same possibly idle CPU on systems that
want to be power-efficient (https://lwn.net/Articles/731052/).

Link: https://lkml.kernel.org/r/20210421105132.3965998-4-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jann Horn <jannh@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 9742649..e18fbbd 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -636,7 +636,8 @@ static void toggle_allocation_gate(struct work_struct *work)
 	/* Disable static key and reset timer. */
 	static_branch_disable(&kfence_allocation_key);
 #endif
-	schedule_delayed_work(&kfence_timer, msecs_to_jiffies(kfence_sample_interval));
+	queue_delayed_work(system_power_efficient_wq, &kfence_timer,
+			   msecs_to_jiffies(kfence_sample_interval));
 }
 static DECLARE_DELAYED_WORK(kfence_timer, toggle_allocation_gate);
 
@@ -665,7 +666,7 @@ void __init kfence_init(void)
 	}
 
 	WRITE_ONCE(kfence_enabled, true);
-	schedule_delayed_work(&kfence_timer, 0);
+	queue_delayed_work(system_power_efficient_wq, &kfence_timer, 0);
 	pr_info("initialized - using %lu bytes for %d objects at 0x%p-0x%p\n", KFENCE_POOL_SIZE,
 		CONFIG_KFENCE_NUM_OBJECTS, (void *)__kfence_pool,
 		(void *)(__kfence_pool + KFENCE_POOL_SIZE));