perf/x86/intel/rapl: Make package handling more robust

The package management code in RAPL relies on package mapping being
available before a CPU is started. This changed with:

  9d85eb9119f4 ("x86/smpboot: Make logical package management more robust")

because the ACPI/BIOS information turned out to be unreliable, but that
left RAPL in broken state. This was not noticed because on a regular boot
all CPUs are online before RAPL is initialized.

A possible fix would be to reintroduce the mess which allocates a package
data structure in CPU prepare and when it turns out to already exist in
starting throw it away later in the CPU online callback. But that's a
horrible hack and not required at all because RAPL becomes functional for
perf only in the CPU online callback. That's correct because user space is
not yet informed about the CPU being onlined, so nothing caan rely on RAPL
being available on that particular CPU.

Move the allocation to the CPU online callback and simplify the hotplug
handling. At this point the package mapping is established and correct.

This also adds a missing check for available package data in the
event_init() function.

Reported-by: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 9d85eb9119f4 ("x86/smpboot: Make logical package management more robust")
Link: http://lkml.kernel.org/r/20170131230141.212593966@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

path: root/tools/perf/CREDITS

Most of the infrastructure that 'perf' uses here has been reused
from the Git project, as of version:

    66996ec: Sync with 1.6.2.4

Here is an (incomplete!) list of main contributors to those files
in util/* and elsewhere:

 Alex Riesen
 Christian Couder
 Dmitry Potapov
 Jeff King
 Johannes Schindelin
 Johannes Sixt
 Junio C Hamano
 Linus Torvalds
 Matthias Kestenholz
 Michal Ostrowski
 Miklos Vajna
 Petr Baudis
 Pierre Habouzit
 René Scharfe
 Samuel Tardieu
 Shawn O. Pearce
 Steffen Prohaska
 Steve Haslam

Thanks guys!

The full history of the files can be found in the upstream Git commits.