Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Tue, 17 Jan 2023 14:30:17 +0100 | Subject | Re: [PATCH] cpufreq: Send CPUFREQ_CREATE_POLICY notification after the perf domain creation. |
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On Mon, Jan 16, 2023 at 12:52 AM Vincent Wang <bhuwz@163.com> wrote: > > From: Vincent Wang <vincentwang3@lenovo.com> > > We found the following issue during kernel boot on android phone: > > [ 1.325272][ T1] cpu cpu0: EM: created perf domain > [ 1.329317][ T1] cpu cpu4: EM: created perf domain > [ 1.337597][ T76] pd_init: no EM found for CPU7 > [ 1.350849][ T1] cpu cpu7: EM: created perf domain > > pd init for cluster2 is executed in a kworker thread and > is earlier than the perf domain creation for cluster2. > > pd_init() is called from the cpufreq notification of > CPUFREQ_CREATE_POLICY in cpufreq_online(), which is earlier > than that cpufreq_driver->register_em() is called. > > To avoid this issue, cpufreq notification should be sent after > the perf domain creation. > > Signed-off-by: Vincent Wang <vincentwang3@lenovo.com> > --- > drivers/cpufreq/cpufreq.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index 7e56a42750ea..af8836069398 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -1430,9 +1430,6 @@ static int cpufreq_online(unsigned int cpu) > policy->max_freq_req = NULL; > goto out_destroy_policy; > } > - > - blocking_notifier_call_chain(&cpufreq_policy_notifier_list, > - CPUFREQ_CREATE_POLICY, policy); > }
AFAICS, in some cases, this may cause cpufreq_online() to send CPUFREQ_REMOVE_POLICY without sending CPUFREQ_CREATE_POLICY which is generally confusing to its callers.
I'm wondering if you can reorder the EM registration before the initialization of frequency QoS for the policy?
> > if (cpufreq_driver->get && has_target()) { > @@ -1506,6 +1503,9 @@ static int cpufreq_online(unsigned int cpu) > */ > if (cpufreq_driver->register_em) > cpufreq_driver->register_em(policy); > + > + blocking_notifier_call_chain(&cpufreq_policy_notifier_list, > + CPUFREQ_CREATE_POLICY, policy); > } > > ret = cpufreq_init_policy(policy); > --
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