From 76ce7cfe35ef58f34e6ba85327afb5fbf6c3ff9b Mon Sep 17 00:00:00 2001 From: Pavel Tatashin Date: Fri, 27 Oct 2017 20:11:00 -0400 Subject: x86/smpboot: Make optimization of delay calibration work correctly If the TSC has constant frequency then the delay calibration can be skipped when it has been calibrated for a package already. This is checked in calibrate_delay_is_known(), but that function is buggy in two aspects: It returns 'false' if (!tsc_disabled && !cpu_has(&cpu_data(cpu), X86_FEATURE_CONSTANT_TSC) which is obviously the reverse of the intended check and the check for the sibling mask cannot work either because the topology links have not been set up yet. Correct the condition and move the call to set_cpu_sibling_map() before invoking calibrate_delay() so the sibling check works correctly. [ tglx: Rewrote changelong ] Fixes: c25323c07345 ("x86/tsc: Use topology functions") Signed-off-by: Pavel Tatashin Signed-off-by: Thomas Gleixner Cc: peterz@infradead.org Cc: bob.picco@oracle.com Cc: steven.sistare@oracle.com Cc: daniel.m.jordan@oracle.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20171028001100.26603-1-pasha.tatashin@oracle.com --- arch/x86/kernel/tsc.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'arch/x86/kernel/tsc.c') diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 796d96b..ad2b925 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1346,12 +1346,10 @@ void __init tsc_init(void) unsigned long calibrate_delay_is_known(void) { int sibling, cpu = smp_processor_id(); - struct cpumask *mask = topology_core_cpumask(cpu); + int constant_tsc = cpu_has(&cpu_data(cpu), X86_FEATURE_CONSTANT_TSC); + const struct cpumask *mask = topology_core_cpumask(cpu); - if (!tsc_disabled && !cpu_has(&cpu_data(cpu), X86_FEATURE_CONSTANT_TSC)) - return 0; - - if (!mask) + if (tsc_disabled || !constant_tsc || !mask) return 0; sibling = cpumask_any_but(mask, cpu); -- cgit v1.1