From: Prarit Bhargava <prarit@redhat.com> To: Viresh Kumar <viresh.kumar@linaro.org> Cc: Stephen Boyd <sboyd@codeaurora.org>, Saravana Kannan <skannan@codeaurora.org>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Lenny Szubowicz <lszubowi@redhat.com>, "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org> Subject: Re: [PATCH] cpufreq, store_scaling_governor requires policy->rwsem to be held for duration of changing governors [v2] Date: Wed, 13 Aug 2014 05:58:18 -0400 [thread overview] Message-ID: <53EB36BA.7050302@redhat.com> (raw) In-Reply-To: <CAKohponqFj5jSpvYbMD5d5zgCJAjCYkNg=_L+BKeMEDmBEWbyg@mail.gmail.com> On 08/13/2014 03:39 AM, Viresh Kumar wrote: > On 12 August 2014 17:03, Prarit Bhargava <prarit@redhat.com> wrote: >> Okay, this is what I have and I can reproduce this *easily* 100% of the time. >> >> I've used your above config options and have enabled LOCKDEP. >> >> In order to restore the locking, I've applied the following patch to the cpufreq >> core (sorry for the cut-and-paste): >> >> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c >> index d9fdedd..dfda238 100644 >> --- a/drivers/cpufreq/cpufreq.c >> +++ b/drivers/cpufreq/cpufreq.c >> @@ -2192,9 +2192,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *polic >> /* end old governor */ >> if (old_gov) { >> __cpufreq_governor(policy, CPUFREQ_GOV_STOP); >> - up_write(&policy->rwsem); >> __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); >> - down_write(&policy->rwsem); >> } >> >> /* start new governor */ >> @@ -2203,9 +2201,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *polic >> if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) >> goto out; >> >> - up_write(&policy->rwsem); >> __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); >> - down_write(&policy->rwsem); >> } >> >> /* new governor failed, so re-start old one */ >> >> >> I've modified the acpi-cpufreq driver to include (sorry for the cut-and-paste) >> >> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c >> index b0c18ed..97653c3 100644 >> --- a/drivers/cpufreq/acpi-cpufreq.c >> +++ b/drivers/cpufreq/acpi-cpufreq.c >> @@ -884,6 +884,9 @@ static struct freq_attr *acpi_cpufreq_attr[] = { >> }; >> >> static struct cpufreq_driver acpi_cpufreq_driver = { >> + .flags = CPUFREQ_STICKY | >> + CPUFREQ_HAVE_GOVERNOR_PER_POLICY | >> + CPUFREQ_NEED_INITIAL_FREQ_CHECK, >> .verify = cpufreq_generic_frequency_table_verify, >> .target_index = acpi_cpufreq_target, >> .bios_limit = acpi_processor_get_bios_limit, >> >> I do a >> >> cat /sys/devices/system/cpu/cpu2/cpufreq/conservative/* >> echo ondemand > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor >> >> and then I immediately see the stack trace. > > What's your system configuration? How many clusters/cpus/etc.. Anywhere from 2-4 sockets, 8 - 240 cpus (depending on # of sockets), x86 arch. P. >
WARNING: multiple messages have this Message-ID (diff)
From: Prarit Bhargava <prarit@redhat.com> To: Viresh Kumar <viresh.kumar@linaro.org> Cc: Stephen Boyd <sboyd@codeaurora.org>, Saravana Kannan <skannan@codeaurora.org>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Lenny Szubowicz <lszubowi@redhat.com>, "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org> Subject: Re: [PATCH] cpufreq, store_scaling_governor requires policy->rwsem to be held for duration of changing governors [v2] Date: Wed, 13 Aug 2014 05:58:18 -0400 [thread overview] Message-ID: <53EB36BA.7050302@redhat.com> (raw) In-Reply-To: <CAKohponqFj5jSpvYbMD5d5zgCJAjCYkNg=_L+BKeMEDmBEWbyg@mail.gmail.com> On 08/13/2014 03:39 AM, Viresh Kumar wrote: > On 12 August 2014 17:03, Prarit Bhargava <prarit@redhat.com> wrote: >> Okay, this is what I have and I can reproduce this *easily* 100% of the time. >> >> I've used your above config options and have enabled LOCKDEP. >> >> In order to restore the locking, I've applied the following patch to the cpufreq >> core (sorry for the cut-and-paste): >> >> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c >> index d9fdedd..dfda238 100644 >> --- a/drivers/cpufreq/cpufreq.c >> +++ b/drivers/cpufreq/cpufreq.c >> @@ -2192,9 +2192,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *polic >> /* end old governor */ >> if (old_gov) { >> __cpufreq_governor(policy, CPUFREQ_GOV_STOP); >> - up_write(&policy->rwsem); >> __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); >> - down_write(&policy->rwsem); >> } >> >> /* start new governor */ >> @@ -2203,9 +2201,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *polic >> if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) >> goto out; >> >> - up_write(&policy->rwsem); >> __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); >> - down_write(&policy->rwsem); >> } >> >> /* new governor failed, so re-start old one */ >> >> >> I've modified the acpi-cpufreq driver to include (sorry for the cut-and-paste) >> >> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c >> index b0c18ed..97653c3 100644 >> --- a/drivers/cpufreq/acpi-cpufreq.c >> +++ b/drivers/cpufreq/acpi-cpufreq.c >> @@ -884,6 +884,9 @@ static struct freq_attr *acpi_cpufreq_attr[] = { >> }; >> >> static struct cpufreq_driver acpi_cpufreq_driver = { >> + .flags = CPUFREQ_STICKY | >> + CPUFREQ_HAVE_GOVERNOR_PER_POLICY | >> + CPUFREQ_NEED_INITIAL_FREQ_CHECK, >> .verify = cpufreq_generic_frequency_table_verify, >> .target_index = acpi_cpufreq_target, >> .bios_limit = acpi_processor_get_bios_limit, >> >> I do a >> >> cat /sys/devices/system/cpu/cpu2/cpufreq/conservative/* >> echo ondemand > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor >> >> and then I immediately see the stack trace. > > What's your system configuration? How many clusters/cpus/etc.. Anywhere from 2-4 sockets, 8 - 240 cpus (depending on # of sockets), x86 arch. P. >
next prev parent reply other threads:[~2014-08-13 9:58 UTC|newest] Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-07-29 11:46 [PATCH] cpufreq, store_scaling_governor requires policy->rwsem to be held for duration of changing governors [v2] Prarit Bhargava 2014-07-30 0:03 ` Rafael J. Wysocki 2014-07-30 14:18 ` Prarit Bhargava 2014-07-30 21:40 ` Rafael J. Wysocki 2014-07-31 1:36 ` Saravana Kannan 2014-07-31 2:16 ` Rafael J. Wysocki 2014-07-31 2:07 ` Saravana Kannan 2014-07-31 10:16 ` Prarit Bhargava 2014-07-31 10:21 ` Prarit Bhargava 2014-07-31 10:23 ` Prarit Bhargava 2014-07-31 16:36 ` Rafael J. Wysocki 2014-07-31 17:57 ` Prarit Bhargava 2014-07-31 18:38 ` Rafael J. Wysocki 2014-07-31 18:26 ` Prarit Bhargava 2014-07-31 20:24 ` Saravana Kannan 2014-07-31 20:30 ` Prarit Bhargava 2014-07-31 20:38 ` Saravana Kannan 2014-07-31 21:08 ` Prarit Bhargava 2014-07-31 22:13 ` Saravana Kannan 2014-07-31 22:58 ` Prarit Bhargava 2014-08-01 0:55 ` Saravana Kannan 2014-08-01 10:24 ` Prarit Bhargava 2014-08-01 10:27 ` Prarit Bhargava 2014-08-01 17:18 ` Stephen Boyd 2014-08-01 19:15 ` Prarit Bhargava 2014-08-01 19:36 ` Stephen Boyd 2014-08-01 19:43 ` Prarit Bhargava 2014-08-01 19:54 ` Stephen Boyd 2014-08-01 21:25 ` Saravana Kannan 2014-08-04 10:11 ` Prarit Bhargava 2014-08-05 7:46 ` Viresh Kumar 2014-08-05 10:47 ` Prarit Bhargava 2014-08-05 10:53 ` Viresh Kumar 2014-08-05 22:06 ` Saravana Kannan 2014-08-05 22:20 ` Prarit Bhargava 2014-08-05 22:40 ` Saravana Kannan 2014-08-05 22:42 ` Prarit Bhargava 2014-08-05 22:51 ` Saravana Kannan 2014-08-13 19:57 ` Prarit Bhargava 2014-08-13 19:57 ` Prarit Bhargava 2014-08-14 18:16 ` Saravana Kannan 2014-08-14 18:16 ` Saravana Kannan 2014-08-06 8:10 ` Viresh Kumar 2014-08-06 10:09 ` Prarit Bhargava 2014-08-06 10:09 ` Prarit Bhargava 2014-08-06 15:08 ` Stephen Boyd 2014-08-07 6:36 ` Viresh Kumar 2014-08-07 10:12 ` Prarit Bhargava 2014-08-07 10:15 ` Viresh Kumar 2014-08-12 9:03 ` Viresh Kumar 2014-08-12 11:33 ` Prarit Bhargava 2014-08-13 7:39 ` Viresh Kumar 2014-08-13 9:58 ` Prarit Bhargava [this message] 2014-08-13 9:58 ` Prarit Bhargava 2014-08-14 4:19 ` Viresh Kumar 2014-08-04 10:36 ` Viresh Kumar 2014-08-04 12:25 ` Prarit Bhargava 2014-08-04 13:38 ` Viresh Kumar 2014-08-04 14:00 ` Prarit Bhargava 2014-08-04 15:04 ` Prarit Bhargava 2014-08-04 20:16 ` Saravana Kannan 2014-08-05 6:14 ` Viresh Kumar 2014-08-05 6:29 ` skannan 2014-08-05 6:43 ` Viresh Kumar 2014-10-13 10:43 ` Viresh Kumar 2014-10-13 11:52 ` Prarit Bhargava
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