The following commit has been merged into the sched/core branch of tip:
Commit-ID: f4291df103315a696f0b8c4f45ca8ae773c17441
Gitweb: https://git.kernel.org/tip/f4291df103315a696f0b8c4f45ca8ae773c17441
Author: Giovanni Gherdovich <ggherdovich@xxxxxxx>
AuthorDate: Sun, 31 May 2020 20:24:53 +02:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Mon, 15 Jun 2020 14:10:02 +02:00
x86, sched: Bail out of frequency invariance if turbo_freq/base_freq gives 0
Be defensive against the case where the processor reports a base_freq
larger than turbo_freq (the ratio would be zero).
Fixes: 1567c3e3467c ("x86, sched: Add support for frequency invariance")
Signed-off-by: Giovanni Gherdovich <ggherdovich@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Link: https://lkml.kernel.org/r/20200531182453.15254-4-ggherdovich@xxxxxxx
---
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 20e1cea..518ac6b 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1977,6 +1977,7 @@ 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;
@@ -2010,9 +2011,15 @@ out:
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;
}
|