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_s96mcnqa56gjfxy45mzc47yg...@mail.gmail.com/ [2] https://lore.kernel.org/lkml/20200422144055.18171-1-ggherdov...@suse.cz/ [3] https://lore.kernel.org/lkml/20200424013222.ga26...@ranerica-svr.sc.intel.com/ 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(-) -- 2.16.4
