From abc81f766904f10b5941e86591cb5ca614064c1a Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Mon, 19 Sep 2016 10:08:03 +0200 Subject: [PATCH 5/5] pm_qos: Allow calling pm_qos functions from MEM_RECLAIM paths Create a specific workqueue for pm_qos with WQ_MEM_RECLAIM set, so that pm_qos functions can be called from MEM_RECLAIM paths. Signed-off-by: Hans de Goede --- include/linux/pm_qos.h | 1 + kernel/power/qos.c | 23 ++++++++++++++++++++++- 2 files changed, 23 insertions(+), 1 deletion(-) diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h index ff597538..611cef3 100644 --- a/include/linux/pm_qos.h +++ b/include/linux/pm_qos.h @@ -46,6 +46,7 @@ struct pm_qos_request { struct plist_node node; int pm_qos_class; struct delayed_work work; /* for pm_qos_update_request_timeout */ + struct workqueue_struct *wq; }; struct pm_qos_flags_request { diff --git a/kernel/power/qos.c b/kernel/power/qos.c index ac131cb..d3dc81f 100644 --- a/kernel/power/qos.c +++ b/kernel/power/qos.c @@ -431,6 +431,26 @@ static void pm_qos_work_fn(struct work_struct *work) } /** + * pm_qos_get_work_queue - get workqueue for scheduling pm_qos_work_fn() on + * + * This returns a wq with WQ_MEM_RECLAIM set as pm_qos functions may get + * called from MEM_RECLAIM paths. + */ +static struct workqueue_struct *pm_qos_get_work_queue(void) +{ + static DEFINE_MUTEX(mutex); + static struct workqueue_struct *wq = NULL; + + mutex_lock(&mutex); + if (!wq) + wq = alloc_workqueue("pm_qos_wq", WQ_MEM_RECLAIM, 0); + mutex_unlock(&mutex); + + /* If alloc_workqueue fails (should never happen) return the systemwq */ + return wq ? wq : system_wq; +} + +/** * pm_qos_add_request - inserts new qos request into the list * @req: pointer to a preallocated handle * @pm_qos_class: identifies which list of qos request to use @@ -455,6 +475,7 @@ void pm_qos_add_request(struct pm_qos_request *req, } req->pm_qos_class = pm_qos_class; INIT_DELAYED_WORK(&req->work, pm_qos_work_fn); + req->wq = pm_qos_get_work_queue(); trace_pm_qos_add_request(pm_qos_class, value); pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints, &req->node, PM_QOS_ADD_REQ, value); @@ -513,7 +534,7 @@ void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value, pm_qos_array[req->pm_qos_class]->constraints, &req->node, PM_QOS_UPDATE_REQ, new_value); - schedule_delayed_work(&req->work, usecs_to_jiffies(timeout_us)); + queue_delayed_work(req->wq, &req->work, usecs_to_jiffies(timeout_us)); } /** -- 2.9.3