kernel/git/stable/linux.git/drivers/cpufreq/cpufreq.c, branch linux-7.2.y

cpufreq: Make cpufreq_update_pressure() fall back to cpuinfo.max_freq

2026-07-09T18:31:57+00:00

If arch_scale_freq_ref() is not defined for a given arch (like x86, for example), cpufreq_update_pressure() will always set cpufreq_pressure to zero for all CPUs in the system, which is generally problematic on systems with asymmetric capacity [1]. However, in the absence of arch_scale_freq_ref(), it is reasonable to assume that cpuinfo.max_freq is the maximum sustainable frequency for the given cpufreq policy. Moreover, there are cases in which arch_scale_freq_ref() would need to be defined to return essentially the cpuinfo.max_freq value anyway (for example, intel_pstate on hybrid platforms). For the above reasons, update cpufreq_update_pressure() to fall back to using cpuinfo.max_freq as the reference frequency if zero is returned by arch_scale_freq_ref(). Fixes: 75d659317bb1 ("cpufreq: Add a cpufreq pressure feedback for the scheduler") Link: https://lore.kernel.org/lkml/CAKfTPtBuRLfYNnR4w--cFZYZy-R8gaPEgVwCcaMmbCcJ2H-muQ@mail.gmail.com/ [1] Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Reviewed-by: Zhongqiu Han Tested-by: Ricardo Neri # cluster scheduling Acked-by: Vincent Guittot Link: https://patch.msgid.link/5086499.GXAFRqVoOG@rafael.j.wysocki

Merge tag 'timers-nohz-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip

2026-06-15T08:18:52+00:00

Pull NOHZ updates from Thomas Gleixner: - Fix a long standing TOCTOU in get_cpu_sleep_time_us() - Make the CPU offline NOHZ handling more robust by disabling NOHZ on the outgoing CPU early instead of creating unneeded state which needs to be undone. - Unify idle CPU time accounting instead of having two different accounting mechanisms. These two different mechanisms are not really independent, but the different properties can in the worst case cause that gloabl idle time can be observed going backwards. - Consolidate the idle/iowait time retrieval interfaces instead of converting back and forth between them. - Make idle interrupt time accounting more robust. The original code assumes that interrupt time accouting is enabled and therefore stops elapsing idle time while an interrupt is handled in NOHZ dyntick state. That assumption is not correct as interrupt time accounting can be disabled at compile and runtime. - Fix an accounting error between dyntick idle time and dyntick idle steal time. The stolen time is not accounted and therefore idle time becomes inaccurate. The stolen time is now accounted after the fact as there is no way to predict the steal time upfront. * tag 'timers-nohz-2026-06-13' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: sched/cputime: Handle dyntick-idle steal time correctly sched/cputime: Handle idle irqtime gracefully sched/cputime: Provide get_cpu_[idle|iowait]_time_us() off-case tick/sched: Consolidate idle time fetching APIs tick/sched: Account tickless idle cputime only when tick is stopped tick/sched: Remove unused fields tick/sched: Move dyntick-idle cputime accounting to cputime code tick/sched: Remove nohz disabled special case in cputime fetch tick/sched: Unify idle cputime accounting s390/time: Prepare to stop elapsing in dynticks-idle powerpc/time: Prepare to stop elapsing in dynticks-idle sched/cputime: Correctly support generic vtime idle time sched/cputime: Remove superfluous and error prone kcpustat_field() parameter sched/idle: Handle offlining first in idle loop tick/sched: Fix TOCTOU in nohz idle time fetch

cpufreq: Use policy->min/max init as QoS request

2026-06-08T16:42:14+00:00

Modify cpufreq_policy_init_qos() introduced previously to use policy->min/max set in the driver .init() callback as the initial values for the policy min/max frequency QoS requests, respectively, so long as they are different from 0 (which means that they have been updated by the driver). Update the documentation in accordance with that code change. This only affects the following drivers: - gx-suspmod (min) - cppc-cpufreq (min) - longrun (min/max) Signed-off-by: Pierre Gondois [ rjw: Changelog rewrite ] Link: https://patch.msgid.link/20260528090913.2759118-5-pierre.gondois@arm.com Signed-off-by: Rafael J. Wysocki

cpufreq: Set default policy->min/max values for all drivers

2026-06-08T16:42:14+00:00

Some drivers set policy->min/max in their .init() callback, but cpufreq_set_policy() will ultimately override them through: cpufreq_policy_online() \-cpufreq_init_policy() \-cpufreq_set_policy() \-/* Set policy->min/max */ Thus the policy min/max values set by the drivers are only temporary. There is an exception if CPUFREQ_NEED_INITIAL_FREQ_CHECK is set and cpufreq_policy_online() calls __cpufreq_driver_target() which invokes cpufreq_driver->target(). To prepare for a subsequent change that will remove all initialization of policy->min/max in driver .init() callbacks if the min/max value is equal to the corresponding cpuinfo.min/max_freq, set default policy->min/max values in the core for all drivers. Signed-off-by: Pierre Gondois Reviewed-by: Jie Zhan [ rjw: Edits of the new comment and changelog ] Link: https://patch.msgid.link/20260528090913.2759118-3-pierre.gondois@arm.com Signed-off-by: Rafael J. Wysocki

cpufreq: Extract cpufreq_policy_init_qos() function

2026-06-08T16:42:14+00:00

Extract the QoS-related logic from cpufreq_policy_online() to make that function shorter/simpler. The logic is placed in cpufreq_policy_init_qos() and is now executed right after the following calls: - cpufreq_driver->init() - cpufreq_table_validate_and_sort() This facilitats subsequent changes that will, in cpufreq_policy_init_qos(): - Set a default policy->min/max value for all policies. - Use the policy->min/max values set by drivers as initial request values for policy frequency QoS requests. No functional change. Signed-off-by: Pierre Gondois Reviewed-by: Zhongqiu Han Reviewed-by: Jie Zhan [ rjw: Changelog edits ] Link: https://patch.msgid.link/20260528090913.2759118-2-pierre.gondois@arm.com Signed-off-by: Rafael J. Wysocki

sched/cputime: Provide get_cpu_[idle|iowait]_time_us() off-case

2026-06-02T19:27:26+00:00

The last reason why get_cpu_idle/iowait_time_us() may return -1 now is if the config doesn't support nohz. The ad-hoc replacement solution by cpufreq is to compute jiffies minus the whole busy cputime. Although the intention should provide a coherent low resolution estimation of the idle and iowait time, the implementation is buggy because jiffies don't start at 0. Just provide instead a real get_cpu_[idle|iowait]_time_us() offcase. Signed-off-by: Frederic Weisbecker Signed-off-by: Thomas Gleixner Tested-by: Shrikanth Hegde Link: https://patch.msgid.link/20260508131647.43868-14-frederic@kernel.org

cpufreq: Avoid redundant target() calls for unchanged limits

2026-05-22T16:41:24+00:00

Drivers setting CPUFREQ_NEED_UPDATE_LIMITS expect target() to be invoked even if the target frequency remains unchanged, so they can update their internal policy limits state. Currently the core invokes target() unconditionally whenever the requested frequency matches policy->cur for such drivers, even if policy->min and policy->max haven't changed since the previous update. Track pending policy limit updates explicitly and skip redundant target() invocations when neither the target frequency nor the effective limits changed. Signed-off-by: Viresh Kumar Reviewed-by: Lifeng Zheng Reviewed-by: Zhongqiu Han Link: https://patch.msgid.link/d0107c364b709abca21acf88072220bc05478594.1779423281.git.viresh.kumar@linaro.org Signed-off-by: Rafael J. Wysocki

cpufreq: Fix hotplug-suspend race during reboot

2026-05-21T15:17:16+00:00

During system reboot, cpufreq_suspend() is called via the kernel_restart() -> device_shutdown() path. Unlike the normal system suspend path, the reboot path does not call freeze_processes(), so userspace processes and kernel threads remain active. This allows CPU hotplug operations to run concurrently with cpufreq_suspend(). The original code has no synchronization with CPU hotplug, leading to a race condition where governor_data can be freed by the hotplug path while cpufreq_suspend() is still accessing it, resulting in a null pointer dereference: Unable to handle kernel NULL pointer dereference Call Trace: do_kernel_fault+0x28/0x3c cpufreq_suspend+0xdc/0x160 device_shutdown+0x18/0x200 kernel_restart+0x40/0x80 arm64_sys_reboot+0x1b0/0x200 Fix this by adding cpus_read_lock()/cpus_read_unlock() to cpufreq_suspend() to block CPU hotplug operations while suspend is in progress. Fixes: 65650b35133f ("cpufreq: Avoid cpufreq_suspend() deadlock on system shutdown") Signed-off-by: Tianxiang Chen Reviewed-by: Zhongqiu Han Cc: All applicable [ rjw: Changelog edits ] Link: https://patch.msgid.link/20260408141914.35281-1-nanmu@xiaomi.com Signed-off-by: Rafael J. Wysocki

Merge tag 'trace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2026-04-17T16:43:12+00:00

Pull tracing updates from Steven Rostedt: - Fix printf format warning for bprintf sunrpc uses a trace_printk() that triggers a printf warning during the compile. Move the __printf() attribute around for when debugging is not enabled the warning will go away - Remove redundant check for EVENT_FILE_FL_FREED in event_filter_write() The FREED flag is checked in the call to event_file_file() and then checked again right afterward, which is unneeded - Clean up event_file_file() and event_file_data() helpers These helper functions played a different role in the past, but now with eventfs, the READ_ONCE() isn't needed. Simplify the code a bit and also add a warning to event_file_data() if the file or its data is not present - Remove updating file->private_data in tracing open All access to the file private data is handled by the helper functions, which do not use file->private_data. Stop updating it on open - Show ENUM names in function arguments via BTF in function tracing When showing the function arguments when func-args option is set for function tracing, if one of the arguments is found to be an enum, show the name of the enum instead of its number - Add new trace_call__##name() API for tracepoints Tracepoints are enabled via static_branch() blocks, where when not enabled, there's only a nop that is in the code where the execution will just skip over it. When tracing is enabled, the nop is converted to a direct jump to the tracepoint code. Sometimes more calculations are required to be performed to update the parameters of the tracepoint. In this case, trace_##name##_enabled() is called which is a static_branch() that gets enabled only when the tracepoint is enabled. This allows the extra calculations to also be skipped by the nop: if (trace_foo_enabled()) { x = bar(); trace_foo(x); } Where the x=bar() is only performed when foo is enabled. The problem with this approach is that there's now two static_branch() calls. One for checking if the tracepoint is enabled, and then again to know if the tracepoint should be called. The second one is redundant Introduce trace_call__foo() that will call the foo() tracepoint directly without doing a static_branch(): if (trace_foo_enabled()) { x = bar(); trace_call__foo(); } - Update various locations to use the new trace_call__##name() API - Move snapshot code out of trace.c Cleaning up trace.c to not be a "dump all", move the snapshot code out of it and into a new trace_snapshot.c file - Clean up some "%*.s" to "%*s" - Allow boot kernel command line options to be called multiple times Have options like: ftrace_filter=foo ftrace_filter=bar ftrace_filter=zoo Equal to: ftrace_filter=foo,bar,zoo - Fix ipi_raise event CPU field to be a CPU field The ipi_raise target_cpus field is defined as a __bitmask(). There is now a __cpumask() field definition. Update the field to use that - Have hist_field_name() use a snprintf() and not a series of strcat() It's safer to use snprintf() that a series of strcat() - Fix tracepoint regfunc balancing A tracepoint can define a "reg" and "unreg" function that gets called before the tracepoint is enabled, and after it is disabled respectively. But on error, after the "reg" func is called and the tracepoint is not enabled, the "unreg" function is not called to tear down what the "reg" function performed - Fix output that shows what histograms are enabled Event variables are displayed incorrectly in the histogram output Instead of "sched.sched_wakeup.$var", it is showing "$sched.sched_wakeup.var" where the '$' is in the incorrect location - Some other simple cleanups * tag 'trace-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (24 commits) selftests/ftrace: Add test case for fully-qualified variable references tracing: Fix fully-qualified variable reference printing in histograms tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func() tracing: Rebuild full_name on each hist_field_name() call tracing: Report ipi_raise target CPUs as cpumask tracing: Remove duplicate latency_fsnotify() stub tracing: Preserve repeated trace_trigger boot parameters tracing: Append repeated boot-time tracing parameters tracing: Remove spurious default precision from show_event_trigger/filter formats cpufreq: Use trace_call__##name() at guarded tracepoint call sites tracing: Remove tracing_alloc_snapshot() when snapshot isn't defined tracing: Move snapshot code out of trace.c and into trace_snapshot.c mm: damon: Use trace_call__##name() at guarded tracepoint call sites btrfs: Use trace_call__##name() at guarded tracepoint call sites spi: Use trace_call__##name() at guarded tracepoint call sites i2c: Use trace_call__##name() at guarded tracepoint call sites kernel: Use trace_call__##name() at guarded tracepoint call sites tracepoint: Add trace_call__##name() API tracing: trace_mmap.h: fix a kernel-doc warning tracing: Pretty-print enum parameters in function arguments ...

Merge tag 'amd-pstate-v7.1-2026-04-02' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux

2026-04-04T18:55:56+00:00

Pull amd-pstate new content for 7.1 (2026-04-02) from Mario Limonciello: "Add support for new features: * CPPC performance priority * Dynamic EPP * Raw EPP * New unit tests for new features Fixes for: * PREEMPT_RT * sysfs files being present when HW missing * Broken/outdated documentation" * tag 'amd-pstate-v7.1-2026-04-02' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/superm1/linux: (22 commits) MAINTAINERS: amd-pstate: Step down as maintainer, add Prateek as reviewer cpufreq: Pass the policy to cpufreq_driver->adjust_perf() cpufreq/amd-pstate: Pass the policy to amd_pstate_update() cpufreq/amd-pstate-ut: Add a unit test for raw EPP cpufreq/amd-pstate: Add support for raw EPP writes cpufreq/amd-pstate: Add support for platform profile class cpufreq/amd-pstate: add kernel command line to override dynamic epp cpufreq/amd-pstate: Add dynamic energy performance preference Documentation: amd-pstate: fix dead links in the reference section cpufreq/amd-pstate: Cache the max frequency in cpudata Documentation/amd-pstate: Add documentation for amd_pstate_floor_{freq,count} Documentation/amd-pstate: List amd_pstate_prefcore_ranking sysfs file Documentation/amd-pstate: List amd_pstate_hw_prefcore sysfs file amd-pstate-ut: Add a testcase to validate the visibility of driver attributes amd-pstate-ut: Add module parameter to select testcases amd-pstate: Introduce a tracepoint trace_amd_pstate_cppc_req2() amd-pstate: Add sysfs support for floor_freq and floor_count amd-pstate: Add support for CPPC_REQ2 and FLOOR_PERF x86/cpufeatures: Add AMD CPPC Performance Priority feature. amd-pstate: Make certain freq_attrs conditionally visible ...