[PATCH v2 3/3] kfence: use power-efficient work queue to run delayed work

From: Marco Elver
Date: Wed Apr 21 2021 - 06:52:17 EST


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 [1].
[1] https://lwn.net/Articles/731052/

Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
---
mm/kfence/core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 9742649f3f88..e18fbbd5d9b4 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));
--
2.31.1.368.gbe11c130af-goog