pm_qos: only schedule work when in interrupt context
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From: Florian Mickler on 15 Jun 2010 13:30 Hi James! On Mon, 14 Jun 2010 16:46:40 +0200 florian(a)mickler.org wrote: > With this patch we only schedule the work when in interrupt context. > > Before update_request was callable from interrupt-context there was a > 1:1 relation between a change in the request-value and a notification. > This patch restores that behaviour for all constraints that have update_request > never called from interrupt context. > > The notifier mutex serializes calls to blocking_notifier_call_chain, so > that we are serialized against any pending or currently executing notification. > > Signed-off-by: Florian Mickler <florian(a)mickler.org> > --- > kernel/pm_qos_params.c | 10 +++++++--- > 1 files changed, 7 insertions(+), 3 deletions(-) > > diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c > index 9346906..c06cae9 100644 > --- a/kernel/pm_qos_params.c > +++ b/kernel/pm_qos_params.c > @@ -152,11 +152,15 @@ static s32 min_compare(s32 v1, s32 v2) > static void pm_qos_call_notifiers(struct pm_qos_object *o, > unsigned long curr_value) > { > - schedule_work(&o->notify); > - > if (o->atomic_notifiers) > atomic_notifier_call_chain(o->atomic_notifiers, > - curr_value, NULL); > + (unsigned long) curr_value, NULL); > + > + if (in_interrupt()) > + schedule_work(&o->notify); > + else > + blocking_notifier_call_chain(o->blocking_notifiers, > + (unsigned long) curr_value, NULL); > } > > static void update_notify(struct work_struct *work) What about this? Is this ok? I don't know if it is benign to use in_interrupt() here. I took this idea from the execute_in_process_context() implementation. If this is ok, should I rebase them on your two pm_qos patches (plists and the kzalloc removal)? Did you already thought about some debugging stuff that would suffice the android needs? I kind of thought about either registerieng some notifier callback or using the perf/tracing infrastructure. But I have not looked into it yet. Cheers, Flo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: James Bottomley on 17 Jun 2010 19:10
On Tue, 2010-06-15 at 19:23 +0200, Florian Mickler wrote: > Hi James! > > On Mon, 14 Jun 2010 16:46:40 +0200 > florian(a)mickler.org wrote: > > > With this patch we only schedule the work when in interrupt context. > > > > Before update_request was callable from interrupt-context there was a > > 1:1 relation between a change in the request-value and a notification. > > This patch restores that behaviour for all constraints that have update_request > > never called from interrupt context. > > > > The notifier mutex serializes calls to blocking_notifier_call_chain, so > > that we are serialized against any pending or currently executing notification. > > > > Signed-off-by: Florian Mickler <florian(a)mickler.org> > > --- > > kernel/pm_qos_params.c | 10 +++++++--- > > 1 files changed, 7 insertions(+), 3 deletions(-) > > > > diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c > > index 9346906..c06cae9 100644 > > --- a/kernel/pm_qos_params.c > > +++ b/kernel/pm_qos_params.c > > @@ -152,11 +152,15 @@ static s32 min_compare(s32 v1, s32 v2) > > static void pm_qos_call_notifiers(struct pm_qos_object *o, > > unsigned long curr_value) > > { > > - schedule_work(&o->notify); > > - > > if (o->atomic_notifiers) > > atomic_notifier_call_chain(o->atomic_notifiers, > > - curr_value, NULL); > > + (unsigned long) curr_value, NULL); > > + > > + if (in_interrupt()) > > + schedule_work(&o->notify); > > + else > > + blocking_notifier_call_chain(o->blocking_notifiers, > > + (unsigned long) curr_value, NULL); > > } > > > > static void update_notify(struct work_struct *work) > > What about this? Is this ok? I don't know if it is benign to use > in_interrupt() here. I took this idea from the > execute_in_process_context() implementation. I think it will work ... but I still think it's over complex given the listed requirements (android seems to only want atomic notifiers from atomic contexts). > If this is ok, should I rebase them on your two pm_qos patches (plists > and the kzalloc removal)? Well, I would say yes. However, for more impartial advice, I'd wait and see what the pm maintainers want. > Did you already thought about some debugging stuff that would suffice > the android needs? I kind of thought about either registerieng some > notifier callback or using the perf/tracing infrastructure. > But I have not looked into it yet. I was just going to try the conversion when the wakelocks stuff was finally in and see if it worked in an android kernel. James -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |