02 Nov, 2017

1 commit

  • Many source files in the tree are missing licensing information, which
    makes it harder for compliance tools to determine the correct license.

    By default all files without license information are under the default
    license of the kernel, which is GPL version 2.

    Update the files which contain no license information with the 'GPL-2.0'
    SPDX license identifier. The SPDX identifier is a legally binding
    shorthand, which can be used instead of the full boiler plate text.

    This patch is based on work done by Thomas Gleixner and Kate Stewart and
    Philippe Ombredanne.

    How this work was done:

    Patches were generated and checked against linux-4.14-rc6 for a subset of
    the use cases:
    - file had no licensing information it it.
    - file was a */uapi/* one with no licensing information in it,
    - file was a */uapi/* one with existing licensing information,

    Further patches will be generated in subsequent months to fix up cases
    where non-standard license headers were used, and references to license
    had to be inferred by heuristics based on keywords.

    The analysis to determine which SPDX License Identifier to be applied to
    a file was done in a spreadsheet of side by side results from of the
    output of two independent scanners (ScanCode & Windriver) producing SPDX
    tag:value files created by Philippe Ombredanne. Philippe prepared the
    base worksheet, and did an initial spot review of a few 1000 files.

    The 4.13 kernel was the starting point of the analysis with 60,537 files
    assessed. Kate Stewart did a file by file comparison of the scanner
    results in the spreadsheet to determine which SPDX license identifier(s)
    to be applied to the file. She confirmed any determination that was not
    immediately clear with lawyers working with the Linux Foundation.

    Criteria used to select files for SPDX license identifier tagging was:
    - Files considered eligible had to be source code files.
    - Make and config files were included as candidates if they contained >5
    lines of source
    - File already had some variant of a license header in it (even if
    Reviewed-by: Philippe Ombredanne
    Reviewed-by: Thomas Gleixner
    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

02 Apr, 2016

1 commit

  • Add a new cpufreq scaling governor, called "schedutil", that uses
    scheduler-provided CPU utilization information as input for making
    its decisions.

    Doing that is possible after commit 34e2c555f3e1 (cpufreq: Add
    mechanism for registering utilization update callbacks) that
    introduced cpufreq_update_util() called by the scheduler on
    utilization changes (from CFS) and RT/DL task status updates.
    In particular, CPU frequency scaling decisions may be based on
    the the utilization data passed to cpufreq_update_util() by CFS.

    The new governor is relatively simple.

    The frequency selection formula used by it depends on whether or not
    the utilization is frequency-invariant. In the frequency-invariant
    case the new CPU frequency is given by

    next_freq = 1.25 * max_freq * util / max

    where util and max are the last two arguments of cpufreq_update_util().
    In turn, if util is not frequency-invariant, the maximum frequency in
    the above formula is replaced with the current frequency of the CPU:

    next_freq = 1.25 * curr_freq * util / max

    The coefficient 1.25 corresponds to the frequency tipping point at
    (util / max) = 0.8.

    All of the computations are carried out in the utilization update
    handlers provided by the new governor. One of those handlers is
    used for cpufreq policies shared between multiple CPUs and the other
    one is for policies with one CPU only (and therefore it doesn't need
    to use any extra synchronization means).

    The governor supports fast frequency switching if that is supported
    by the cpufreq driver in use and possible for the given policy.
    In the fast switching case, all operations of the governor take
    place in its utilization update handlers. If fast switching cannot
    be used, the frequency switch operations are carried out with the
    help of a work item which only calls __cpufreq_driver_target()
    (under a mutex) to trigger a frequency update (to a value already
    computed beforehand in one of the utilization update handlers).

    Currently, the governor treats all of the RT and DL tasks as
    "unknown utilization" and sets the frequency to the allowed
    maximum when updated from the RT or DL sched classes. That
    heavy-handed approach should be replaced with something more
    subtle and specifically targeted at RT and DL tasks.

    The governor shares some tunables management code with the
    "ondemand" and "conservative" governors and uses some common
    definitions from cpufreq_governor.h, but apart from that it
    is stand-alone.

    Signed-off-by: Rafael J. Wysocki
    Acked-by: Viresh Kumar
    Acked-by: Peter Zijlstra (Intel)

    Rafael J. Wysocki
     

05 Feb, 2016

1 commit


30 Jan, 2015

1 commit


26 Jan, 2013

1 commit

  • The text in Documentation said it would be removed in 2.6.41;
    the text in the Kconfig said removal in the 3.1 release. Either
    way you look at it, we are well past both, so push it off a cliff.

    Note that the POWER_CSTATE and the POWER_PSTATE are part of the
    legacy tracing API. Remove all tracepoints which use these flags.
    As can be seen from context, most already have a trace entry via
    trace_cpu_idle anyways.

    Also, the cpufreq/cpufreq.c PSTATE one is actually unpaired, as
    compared to the CSTATE ones which all have a clear start/stop.
    As part of this, the trace_power_frequency also becomes orphaned,
    so it too is deleted.

    Signed-off-by: Paul Gortmaker
    Acked-by: Steven Rostedt
    Signed-off-by: Rafael J. Wysocki

    Paul Gortmaker
     

04 Jan, 2011

2 commits

  • Add these new power trace events:

    power:cpu_idle
    power:cpu_frequency
    power:machine_suspend

    The old C-state/idle accounting events:
    power:power_start
    power:power_end

    Have now a replacement (but we are still keeping the old
    tracepoints for compatibility):

    power:cpu_idle

    and
    power:power_frequency

    is replaced with:
    power:cpu_frequency

    power:machine_suspend is newly introduced.

    Jean Pihet has a patch integrated into the generic layer
    (kernel/power/suspend.c) which will make use of it.

    the type= field got removed from both, it was never
    used and the type is differed by the event type itself.

    perf timechart userspace tool gets adjusted in a separate patch.

    Signed-off-by: Thomas Renninger
    Signed-off-by: Ingo Molnar
    Acked-by: Arjan van de Ven
    Acked-by: Jean Pihet
    Cc: Arnaldo Carvalho de Melo
    Cc: Peter Zijlstra
    Cc: Linus Torvalds
    Cc: rjw@sisk.pl
    LKML-Reference:
    Signed-off-by: Ingo Molnar
    LKML-Reference:

    Thomas Renninger
     
  • power_frequency moved to drivers/cpufreq/cpufreq.c which has
    to be compiled in, no need to export it.

    intel_idle can a be module though...

    Signed-off-by: Thomas Renninger
    Signed-off-by: Ingo Molnar
    Acked-by: Jean Pihet
    Cc: Jean Pihet
    Cc: Arjan van de Ven
    Cc: rjw@sisk.pl
    LKML-Reference:
    Signed-off-by: Ingo Molnar
    LKML-Reference:

    Thomas Renninger
     

30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

14 Dec, 2009

1 commit

  • trace_power_start and trace_power_end are used in
    arch/x86/kernel/power.c, and this file can't be compiled
    as a module, so these two tracepoints don't need to be
    exported.

    Signed-off-by: Li Zefan
    Acked-by: Arjan van de Ven
    Acked-by: Steven Rostedt
    LKML-Reference:
    Signed-off-by: Frederic Weisbecker

    Li Zefan
     

19 Sep, 2009

1 commit

  • This patch converts the existing power tracer into an event tracer,
    so that power events (C states and frequency changes) can be
    tracked via "perf".

    This also removes the perl script that was used to demo the tracer;
    its functionality is being replaced entirely with timechart.

    Signed-off-by: Arjan van de Ven
    Acked-by: Peter Zijlstra
    Cc: Paul Mackerras
    Cc: Frederic Weisbecker
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Arjan van de Ven