[tip:x86/mrst] x86: Avoid check hlt for newer cpus
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From: tip-bot for Jacob Pan on 7 May 2010 18:40 Commit-ID: 2b107d93635616db0c3f893c8cc2e6d5cd8d77b2 Gitweb: http://git.kernel.org/tip/2b107d93635616db0c3f893c8cc2e6d5cd8d77b2 Author: Jacob Pan <jacob.jun.pan(a)linux.intel.com> AuthorDate: Fri, 7 May 2010 14:59:45 -0700 Committer: H. Peter Anvin <hpa(a)zytor.com> CommitDate: Fri, 7 May 2010 15:31:17 -0700 x86: Avoid check hlt for newer cpus Check hlt instruction was targeted for some older CPUs. It is an expensive operation in that it takes 4 ticks to break out the check. We can avoid such check completely for newer x86 cpus (family >= 5). [ hpa: corrected family > 5 to family >= 5 ] Signed-off-by: Jacob Pan <jacob.jun.pan(a)linux.intel.com> LKML-Reference: <1273269585-14346-1-git-send-email-jacob.jun.pan(a)linux.intel.com> Signed-off-by: H. Peter Anvin <hpa(a)zytor.com> --- arch/x86/kernel/cpu/bugs.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 01a2652..c39576c 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -86,7 +86,7 @@ static void __init check_fpu(void) static void __init check_hlt(void) { - if (paravirt_enabled()) + if (boot_cpu_data.x86 >= 5 || paravirt_enabled()) return; printk(KERN_INFO "Checking 'hlt' instruction... "); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |