On Sun, May 31, 2020 at 8:26 PM Giovanni Gherdovich <[email protected]> wrote: > > Be defensive against the case where the processor reports a base_freq > larger than turbo_freq (the ratio would be zero). > > Signed-off-by: Giovanni Gherdovich <[email protected]> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]> > Fixes: 1567c3e3467c ("x86, sched: Add support for frequency invariance")
Reviewed-by: Rafael J. Wysocki <[email protected]> > --- > arch/x86/kernel/smpboot.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c > index fe154c8226ba..f619007f46cf 100644 > --- a/arch/x86/kernel/smpboot.c > +++ b/arch/x86/kernel/smpboot.c > @@ -1976,6 +1976,7 @@ static bool core_set_max_freq_ratio(u64 *base_freq, u64 > *turbo_freq) > static bool intel_set_max_freq_ratio(void) > { > u64 base_freq, turbo_freq; > + u64 turbo_ratio; > > if (slv_set_max_freq_ratio(&base_freq, &turbo_freq)) > goto out; > @@ -2009,9 +2010,15 @@ static bool intel_set_max_freq_ratio(void) > return false; > } > > - arch_turbo_freq_ratio = div_u64(turbo_freq * SCHED_CAPACITY_SCALE, > - base_freq); > + turbo_ratio = div_u64(turbo_freq * SCHED_CAPACITY_SCALE, base_freq); > + if (!turbo_ratio) { > + pr_debug("Non-zero turbo and base frequencies led to a 0 > ratio.\n"); > + return false; > + } > + > + arch_turbo_freq_ratio = turbo_ratio; > arch_set_max_freq_ratio(turbo_disabled()); > + > return true; > } > > -- > 2.16.4 >
