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Date: Sat, 24 Mar 2012 11:37:12 -0700
From: mark gross <markgross@...gnar.org>
To: mark gross <markgross@...gnar.org>
Cc: MyungJoo Ham <myungjoo.ham@...sung.com>,
"Rafael J. Wysocki" <rjw@...k.pl>, linux-pm@...r.kernel.org,
Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
Kevin Hilman <khilman@...com>, Jean Pihet <j-pihet@...com>,
kyungmin.park@...sung.com, myungjoo.ham@...il.com,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] PM / QoS: add pm_qos_update_request_timeout API
On Sat, Mar 24, 2012 at 09:41:22AM -0700, mark gross wrote:
> 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@...sung.com>
> > Signed-off-by: Kyungmin Park <kyungmin.park@...sung.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);
> > 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);
> this should be pm_qos_remove_request (req);
>
on second thought your implementation is right. pm_qos_remove_request
is wrong.
--mark
>
> > +}
> > +
> > +/**
> > * 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
> >
--
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