* [RFC][PATCH] cpufreq: intel_pstate: Delete intel_pstate sysfs if failed to register the driver
@ 2020-10-09 3:30 Chen Yu
2020-10-12 13:22 ` srinivas pandruvada
2020-10-16 14:34 ` Rafael J. Wysocki
0 siblings, 2 replies; 4+ messages in thread
From: Chen Yu @ 2020-10-09 3:30 UTC (permalink / raw)
To: Srinivas Pandruvada, Len Brown, Rafael J. Wysocki, Viresh Kumar
Cc: linux-pm, linux-kernel, Chen Yu
There is a corner case that if the intel_pstate driver failed to be
registered(might be due to invalid MSR access) and with the acpi_cpufreq
loaded, the intel_pstate sysfs might still be created, which makes the
user confusing(turbostat for example):
grep . /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
acpi-cpufreq
grep . /sys/devices/system/cpu/intel_pstate/*
/sys/devices/system/cpu/intel_pstate/max_perf_pct:0
/sys/devices/system/cpu/intel_pstate/min_perf_pct:0
grep: /sys/devices/system/cpu/intel_pstate/no_turbo: Resource temporarily unavailable
grep: /sys/devices/system/cpu/intel_pstate/num_pstates: Resource temporarily unavailable
/sys/devices/system/cpu/intel_pstate/status:off
grep: /sys/devices/system/cpu/intel_pstate/turbo_pct: Resource temporarily unavailable
The existing of intel_pstate sysfs does not mean that the intel_pstate driver
has been successfully loaded(for example, echo off to status), but the
intel_pstate sysfs should not co-exist when acpi-cpufreq is also present.
Fix this issue by deleting the intel_pstate sysfs if the driver failed
to be loaded during bootup.
Reported-by: Wendy Wang <wendy.wang@intel.com>
Suggested-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
---
drivers/cpufreq/intel_pstate.c | 24 +++++++++++++++++++++++-
1 file changed, 23 insertions(+), 1 deletion(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 9a515c460a00..8c5f9680de83 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -1420,6 +1420,26 @@ static void __init intel_pstate_sysfs_expose_params(void)
}
}
+static void __init intel_pstate_sysfs_clean(void)
+{
+ if (!intel_pstate_kobject)
+ return;
+
+ sysfs_remove_group(intel_pstate_kobject, &intel_pstate_attr_group);
+
+ if (per_cpu_limits)
+ goto release_kobj;
+
+ sysfs_remove_file(intel_pstate_kobject, &max_perf_pct.attr);
+ sysfs_remove_file(intel_pstate_kobject, &min_perf_pct.attr);
+
+ if (x86_match_cpu(intel_pstate_cpu_ee_disable_ids))
+ sysfs_remove_file(intel_pstate_kobject, &energy_efficiency.attr);
+
+release_kobj:
+ kobject_put(intel_pstate_kobject);
+}
+
static void intel_pstate_sysfs_expose_hwp_dynamic_boost(void)
{
int rc;
@@ -3063,8 +3083,10 @@ static int __init intel_pstate_init(void)
mutex_lock(&intel_pstate_driver_lock);
rc = intel_pstate_register_driver(default_driver);
mutex_unlock(&intel_pstate_driver_lock);
- if (rc)
+ if (rc) {
+ intel_pstate_sysfs_clean();
return rc;
+ }
if (hwp_active) {
const struct x86_cpu_id *id;
--
2.17.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [RFC][PATCH] cpufreq: intel_pstate: Delete intel_pstate sysfs if failed to register the driver
2020-10-09 3:30 [RFC][PATCH] cpufreq: intel_pstate: Delete intel_pstate sysfs if failed to register the driver Chen Yu
@ 2020-10-12 13:22 ` srinivas pandruvada
2020-10-13 6:44 ` Chen Yu
2020-10-16 14:34 ` Rafael J. Wysocki
1 sibling, 1 reply; 4+ messages in thread
From: srinivas pandruvada @ 2020-10-12 13:22 UTC (permalink / raw)
To: Chen Yu, Len Brown, Rafael J. Wysocki, Viresh Kumar
Cc: linux-pm, linux-kernel
On Fri, 2020-10-09 at 11:30 +0800, Chen Yu wrote:
> There is a corner case that if the intel_pstate driver failed to be
> registered(might be due to invalid MSR access)
Do you have logs why it is not loaded? On supported platforms MSRs
should be invalid.
It may be a case when we are trying to bring up pre-production systems
where some instability in MSRs on certain CPUs.
But the patch is correct. We can't have invalid folder when
intel_pstate is not used.
> and with the acpi_cpufreq
> loaded, the intel_pstate sysfs might still be created, which makes
> the
> user confusing(turbostat for example):
>
> grep . /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
> acpi-cpufreq
>
> grep . /sys/devices/system/cpu/intel_pstate/*
> /sys/devices/system/cpu/intel_pstate/max_perf_pct:0
> /sys/devices/system/cpu/intel_pstate/min_perf_pct:0
> grep: /sys/devices/system/cpu/intel_pstate/no_turbo: Resource
> temporarily unavailable
> grep: /sys/devices/system/cpu/intel_pstate/num_pstates: Resource
> temporarily unavailable
> /sys/devices/system/cpu/intel_pstate/status:off
> grep: /sys/devices/system/cpu/intel_pstate/turbo_pct: Resource
> temporarily unavailable
>
> The existing of intel_pstate sysfs does not mean that the
> intel_pstate driver
> has been successfully loaded(for example, echo off to status), but
> the
> intel_pstate sysfs should not co-exist when acpi-cpufreq is also
> present.
> Fix this issue by deleting the intel_pstate sysfs if the driver
> failed
> to be loaded during bootup.
>
> Reported-by: Wendy Wang <wendy.wang@intel.com>
> Suggested-by: Zhang Rui <rui.zhang@intel.com>
> Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com
> --->
> drivers/cpufreq/intel_pstate.c | 24 +++++++++++++++++++++++-
> 1 file changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/intel_pstate.c
> b/drivers/cpufreq/intel_pstate.c
> index 9a515c460a00..8c5f9680de83 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -1420,6 +1420,26 @@ static void __init
> intel_pstate_sysfs_expose_params(void)
> }
> }
>
> +static void __init intel_pstate_sysfs_clean(void)
> +{
> + if (!intel_pstate_kobject)
> + return;
> +
> + sysfs_remove_group(intel_pstate_kobject,
> &intel_pstate_attr_group);
> +
> + if (per_cpu_limits)
> + goto release_kobj;
> +
> + sysfs_remove_file(intel_pstate_kobject, &max_perf_pct.attr);
> + sysfs_remove_file(intel_pstate_kobject, &min_perf_pct.attr);
> +
> + if (x86_match_cpu(intel_pstate_cpu_ee_disable_ids))
> + sysfs_remove_file(intel_pstate_kobject,
> &energy_efficiency.attr);
> +
> +release_kobj:
> + kobject_put(intel_pstate_kobject);
> +}
> +
> static void intel_pstate_sysfs_expose_hwp_dynamic_boost(void)
> {
> int rc;
> @@ -3063,8 +3083,10 @@ static int __init intel_pstate_init(void)
> mutex_lock(&intel_pstate_driver_lock);
> rc = intel_pstate_register_driver(default_driver);
> mutex_unlock(&intel_pstate_driver_lock);
> - if (rc)
> + if (rc) {
> + intel_pstate_sysfs_clean();
> return rc;
> + }
>
> if (hwp_active) {
> const struct x86_cpu_id *id;
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RFC][PATCH] cpufreq: intel_pstate: Delete intel_pstate sysfs if failed to register the driver
2020-10-12 13:22 ` srinivas pandruvada
@ 2020-10-13 6:44 ` Chen Yu
0 siblings, 0 replies; 4+ messages in thread
From: Chen Yu @ 2020-10-13 6:44 UTC (permalink / raw)
To: srinivas pandruvada
Cc: Len Brown, Rafael J. Wysocki, Viresh Kumar, Wendy Wang,
Zhang Rui, linux-pm, linux-kernel
Hi Srinivas,
On Mon, Oct 12, 2020 at 06:22:40AM -0700, srinivas pandruvada wrote:
> On Fri, 2020-10-09 at 11:30 +0800, Chen Yu wrote:
> > There is a corner case that if the intel_pstate driver failed to be
> > registered(might be due to invalid MSR access)
> Do you have logs why it is not loaded? On supported platforms MSRs
> should be invalid.
Unfortunately we don't have the boot up log for now, as it is
a pre-production platform and the low-level simulation(for MSR)
might be unstable.( And there seems to be some environment issue
on pre-production platform to reproduce this issue).
But we can hack the code in intel_pstate to make the driver failed
to be loaded and the issue was reproduced.
> It may be a case when we are trying to bring up pre-production systems
> where some instability in MSRs on certain CPUs.
>
> But the patch is correct. We can't have invalid folder when
> intel_pstate is not used.
>
> > and with the acpi_cpufreq
> > loaded, the intel_pstate sysfs might still be created, which makes
> > the
> > user confusing(turbostat for example):
> >
> > grep . /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
> > acpi-cpufreq
> >
> > grep . /sys/devices/system/cpu/intel_pstate/*
> > /sys/devices/system/cpu/intel_pstate/max_perf_pct:0
> > /sys/devices/system/cpu/intel_pstate/min_perf_pct:0
> > grep: /sys/devices/system/cpu/intel_pstate/no_turbo: Resource
> > temporarily unavailable
> > grep: /sys/devices/system/cpu/intel_pstate/num_pstates: Resource
> > temporarily unavailable
> > /sys/devices/system/cpu/intel_pstate/status:off
> > grep: /sys/devices/system/cpu/intel_pstate/turbo_pct: Resource
> > temporarily unavailable
> >
> > The existing of intel_pstate sysfs does not mean that the
> > intel_pstate driver
> > has been successfully loaded(for example, echo off to status), but
> > the
> > intel_pstate sysfs should not co-exist when acpi-cpufreq is also
> > present.
> > Fix this issue by deleting the intel_pstate sysfs if the driver
> > failed
> > to be loaded during bootup.
> >
> > Reported-by: Wendy Wang <wendy.wang@intel.com>
> > Suggested-by: Zhang Rui <rui.zhang@intel.com>
> > Signed-off-by: Chen Yu <yu.c.chen@intel.com>
> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com
Thanks!
Best,
Chenyu
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RFC][PATCH] cpufreq: intel_pstate: Delete intel_pstate sysfs if failed to register the driver
2020-10-09 3:30 [RFC][PATCH] cpufreq: intel_pstate: Delete intel_pstate sysfs if failed to register the driver Chen Yu
2020-10-12 13:22 ` srinivas pandruvada
@ 2020-10-16 14:34 ` Rafael J. Wysocki
1 sibling, 0 replies; 4+ messages in thread
From: Rafael J. Wysocki @ 2020-10-16 14:34 UTC (permalink / raw)
To: Chen Yu
Cc: Srinivas Pandruvada, Len Brown, Rafael J. Wysocki, Viresh Kumar,
Linux PM, Linux Kernel Mailing List
On Fri, Oct 9, 2020 at 5:29 AM Chen Yu <yu.c.chen@intel.com> wrote:
>
> There is a corner case that if the intel_pstate driver failed to be
> registered(might be due to invalid MSR access) and with the acpi_cpufreq
> loaded, the intel_pstate sysfs might still be created, which makes the
> user confusing(turbostat for example):
>
> grep . /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
> acpi-cpufreq
>
> grep . /sys/devices/system/cpu/intel_pstate/*
> /sys/devices/system/cpu/intel_pstate/max_perf_pct:0
> /sys/devices/system/cpu/intel_pstate/min_perf_pct:0
> grep: /sys/devices/system/cpu/intel_pstate/no_turbo: Resource temporarily unavailable
> grep: /sys/devices/system/cpu/intel_pstate/num_pstates: Resource temporarily unavailable
> /sys/devices/system/cpu/intel_pstate/status:off
> grep: /sys/devices/system/cpu/intel_pstate/turbo_pct: Resource temporarily unavailable
>
> The existing of intel_pstate sysfs does not mean that the intel_pstate driver
> has been successfully loaded(for example, echo off to status), but the
> intel_pstate sysfs should not co-exist when acpi-cpufreq is also present.
> Fix this issue by deleting the intel_pstate sysfs if the driver failed
> to be loaded during bootup.
>
> Reported-by: Wendy Wang <wendy.wang@intel.com>
> Suggested-by: Zhang Rui <rui.zhang@intel.com>
> Signed-off-by: Chen Yu <yu.c.chen@intel.com>
> ---
> drivers/cpufreq/intel_pstate.c | 24 +++++++++++++++++++++++-
> 1 file changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index 9a515c460a00..8c5f9680de83 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -1420,6 +1420,26 @@ static void __init intel_pstate_sysfs_expose_params(void)
> }
> }
>
> +static void __init intel_pstate_sysfs_clean(void)
> +{
> + if (!intel_pstate_kobject)
> + return;
> +
> + sysfs_remove_group(intel_pstate_kobject, &intel_pstate_attr_group);
> +
> + if (per_cpu_limits)
> + goto release_kobj;
> +
> + sysfs_remove_file(intel_pstate_kobject, &max_perf_pct.attr);
> + sysfs_remove_file(intel_pstate_kobject, &min_perf_pct.attr);
> +
> + if (x86_match_cpu(intel_pstate_cpu_ee_disable_ids))
> + sysfs_remove_file(intel_pstate_kobject, &energy_efficiency.attr);
> +
> +release_kobj:
> + kobject_put(intel_pstate_kobject);
> +}
> +
> static void intel_pstate_sysfs_expose_hwp_dynamic_boost(void)
> {
> int rc;
> @@ -3063,8 +3083,10 @@ static int __init intel_pstate_init(void)
> mutex_lock(&intel_pstate_driver_lock);
> rc = intel_pstate_register_driver(default_driver);
> mutex_unlock(&intel_pstate_driver_lock);
> - if (rc)
> + if (rc) {
> + intel_pstate_sysfs_clean();
> return rc;
> + }
>
> if (hwp_active) {
> const struct x86_cpu_id *id;
> --
Applied as 5.10-rc material with some minor changes and the Srinivas'
ACK, thanks!
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-10-09 3:30 [RFC][PATCH] cpufreq: intel_pstate: Delete intel_pstate sysfs if failed to register the driver Chen Yu
2020-10-12 13:22 ` srinivas pandruvada
2020-10-13 6:44 ` Chen Yu
2020-10-16 14:34 ` Rafael J. Wysocki
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