Messages in this thread | | | Date | Sat, 24 Mar 2012 09:35:42 -0700 | From | mark gross <> | Subject | Re: [PATCH v3] PM / QoS: add pm_qos_update_request_timeout API |
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I apologize for the lat replay and admit that I was probably wrong to oppose the idea of time out pm_qos requests. (last week we bumped into a need for them and now I get it.)
On Wed, Mar 07, 2012 at 02:06:18PM +0900, MyungJoo Ham wrote: > The new API, pm_qos_update_request_timeout() is to provide a timeout > with pm_qos_update_request. > > For example, pm_qos_update_request_timeout(req, 100, 1000), means that > QoS request on req with value 100 will be active for 1000 jiffies. > After 1000 jiffies, the QoS request thru req is rolled back to the > request status when pm_qos_update_request_timeout() was called. If there > were another pm_qos_update_request(req, x) during the 1000 jiffies, this > new request with value x will override as this is another request on the > same req handle. A new request on the same req handle will always > override the previous request whether it is the conventional request or > it is the new timeout request. > > Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> > Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> > --- > Changes from v2 > - Rebased to avoid merge conflict > Chages from v1(RFC) > - The semmantics of timeout changed. A timeout now means that the > corresponding qos-req object is being cancelled, not rolling back to > the qos request state at the time of API call. With this changes, > combined with the conventional update_request API, there exists up to > only one qos request per qos-req object. > - The timeout values is expressed in ms (1/1000 sec), not jiffies. > - Style changes, removing unnecessary changes. > - Bugfixes regarding pending timeout work. > > --- > include/linux/pm_qos.h | 4 +++ > kernel/power/qos.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 54 insertions(+), 0 deletions(-) > > diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h > index 0ee7caa..6f347fe 100644 > --- a/include/linux/pm_qos.h > +++ b/include/linux/pm_qos.h > @@ -8,6 +8,7 @@ > #include <linux/notifier.h> > #include <linux/miscdevice.h> > #include <linux/device.h> > +#include <linux/workqueue.h> > > enum { > PM_QOS_RESERVED = 0, > @@ -33,6 +34,7 @@ enum { > struct pm_qos_request { > struct plist_node node; > int pm_qos_class; > + struct delayed_work work; /* for pm_qos_update_request_timeout */ > }; > > struct dev_pm_qos_request { > @@ -77,6 +79,8 @@ void pm_qos_add_request(struct pm_qos_request *req, int pm_qos_class, > s32 value); > void pm_qos_update_request(struct pm_qos_request *req, > s32 new_value); > +void pm_qos_update_request_timeout(struct pm_qos_request *req, > + s32 new_value, unsigned long timeout_ms); is ms the right units? could we ever need us?
> void pm_qos_remove_request(struct pm_qos_request *req); > > int pm_qos_request(int pm_qos_class); > diff --git a/kernel/power/qos.c b/kernel/power/qos.c > index 3e122db..8ac8eca 100644 > --- a/kernel/power/qos.c > +++ b/kernel/power/qos.c > @@ -259,6 +259,21 @@ int pm_qos_request_active(struct pm_qos_request *req) > EXPORT_SYMBOL_GPL(pm_qos_request_active); > > /** > + * pm_qos_work_fn - the timeout handler of pm_qos_update_request_timeout > + * @work: work struct for the delayed work (timeout) > + * > + * This cancels the timeout request by falling back to the default at timeout. > + */ > +static void pm_qos_work_fn(struct work_struct *work) > +{ > + struct pm_qos_request *req = container_of(to_delayed_work(work), > + struct pm_qos_request, > + work); > + > + pm_qos_update_request(req, PM_QOS_DEFAULT_VALUE); > +} > + > +/** > * 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 > @@ -282,6 +297,7 @@ void pm_qos_add_request(struct pm_qos_request *req, > return; > } > req->pm_qos_class = pm_qos_class; > + INIT_DELAYED_WORK(&req->work, pm_qos_work_fn); > pm_qos_update_target(pm_qos_array[pm_qos_class]->constraints, > &req->node, PM_QOS_ADD_REQ, value); > } > @@ -308,6 +324,9 @@ void pm_qos_update_request(struct pm_qos_request *req, > return; > } > > + if (delayed_work_pending(&req->work)) > + cancel_delayed_work_sync(&req->work); > + > if (new_value != req->node.prio) > pm_qos_update_target( > pm_qos_array[req->pm_qos_class]->constraints, > @@ -316,6 +335,34 @@ void pm_qos_update_request(struct pm_qos_request *req, > EXPORT_SYMBOL_GPL(pm_qos_update_request); > > /** > + * pm_qos_update_request_timeout - modifies an existing qos request temporarily. > + * @req : handle to list element holding a pm_qos request to use > + * @new_value: defines the temporal qos request > + * @timeout_ms: the effective duration of this qos request in msecs. > + * > + * After timeout_ms, this qos request is cancelled automatically. > + */ > +void pm_qos_update_request_timeout(struct pm_qos_request *req, s32 new_value, > + unsigned long timeout_ms) > +{ > + if (!req) > + return; > + if (WARN(!pm_qos_request_active(req), > + "%s called for unknown object.", __func__)) > + return; > + > + if (delayed_work_pending(&req->work)) > + cancel_delayed_work_sync(&req->work); > + > + if (new_value != req->node.prio) > + pm_qos_update_target( > + pm_qos_array[req->pm_qos_class]->constraints, > + &req->node, PM_QOS_UPDATE_REQ, new_value); > + > + schedule_delayed_work(&req->work, msecs_to_jiffies(timeout_ms)); > +} > + > +/** > * pm_qos_remove_request - modifies an existing qos request > * @req: handle to request list element > * > @@ -334,6 +381,9 @@ void pm_qos_remove_request(struct pm_qos_request *req) > return; > } > > + if (delayed_work_pending(&req->work)) > + cancel_delayed_work_sync(&req->work); > + > pm_qos_update_target(pm_qos_array[req->pm_qos_class]->constraints, > &req->node, PM_QOS_REMOVE_REQ, > PM_QOS_DEFAULT_VALUE); > -- > 1.7.4.1 >
Acked-by: Mark Gross <markgross@thegnar.org>
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