Commit-ID: 9514ececa52e9f1436e7682e98c852d1338b699f Gitweb: https://git.kernel.org/tip/9514ececa52e9f1436e7682e98c852d1338b699f Author: [email protected] <[email protected]> AuthorDate: Thu, 12 Oct 2017 11:32:03 -0500 Committer: Thomas Gleixner <[email protected]> CommitDate: Mon, 16 Oct 2017 22:50:36 +0200
x86/tsc: Skip TSC test and error messages if already unstable If the TSC has already been determined to be unstable, then checking TSC ADJUST values is a waste of time and generates unnecessary error messages. Signed-off-by: Mike Travis <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Dimitri Sivanich <[email protected]> Reviewed-by: Russ Anderson <[email protected]> Reviewed-by: Peter Zijlstra <[email protected]> Cc: Prarit Bhargava <[email protected]> Cc: Andrew Banman <[email protected]> Cc: Bin Gao <[email protected]> Link: https://lkml.kernel.org/r/[email protected] --- arch/x86/kernel/tsc_sync.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c index 3873dcd..3bdb983 100644 --- a/arch/x86/kernel/tsc_sync.c +++ b/arch/x86/kernel/tsc_sync.c @@ -52,6 +52,10 @@ void tsc_verify_tsc_adjust(bool resume) if (!boot_cpu_has(X86_FEATURE_TSC_ADJUST)) return; + /* Skip unnecessary error messages if TSC already unstable */ + if (check_tsc_unstable()) + return; + /* Rate limit the MSR check */ if (!resume && time_before(jiffies, adj->nextcheck)) return; @@ -114,6 +118,10 @@ bool __init tsc_store_and_check_tsc_adjust(bool bootcpu) if (!boot_cpu_has(X86_FEATURE_TSC_ADJUST)) return false; + /* Skip unnecessary error messages if TSC already unstable */ + if (check_tsc_unstable()) + return false; + rdmsrl(MSR_IA32_TSC_ADJUST, bootval); cur->bootval = bootval; cur->nextcheck = jiffies + HZ;
