Patch 1/2 prevents a division by zero in case the product
"delta_MPERF * arch_max_freq_ratio" overflows u64, as suggested by Linus at [1].
This patch supersedes the version at [2], as it also disables frequency
invariance when that overflow happens.
Patch 2/2 implements the recommendation by Ricardo Neri to check for an all
zero MSR_TURBO_RATIO_LIMIT and disable freq invariance in that case too.
[1] https://lore.kernel.org/lkml/CAHk-=wiX+NT2yxtdPszH9U_S96MCNQA56GJFXY45mZc47yG5KQ@mail.gmail.com/
[2] https://lore.kernel.org/lkml/[email protected]/
[3] https://lore.kernel.org/lkml/[email protected]/
Giovanni Gherdovich (2):
x86, sched: Prevent divisions by zero in frequency invariant
accounting
x86, sched: Bail out of frequency invariance if turbo frequency is
unknown
arch/x86/kernel/smpboot.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)
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2.16.4