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| author | Ingo Molnar <mingo@kernel.org> | 2015-04-23 11:26:08 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-05-19 15:47:22 +0200 |
| commit | 9a89b02918c03d91e685d06e49a652da5f35befc (patch) | |
| tree | bf9aa672b04158abd0f37e1d2486bfcb9479831a /arch/x86/kernel/fpu/xsave.c | |
| parent | x86/fpu: Add debugging check to fpu_copy() (diff) | |
| download | linux-9a89b02918c03d91e685d06e49a652da5f35befc.tar.xz linux-9a89b02918c03d91e685d06e49a652da5f35befc.zip | |
x86/fpu: Print out whether we are doing lazy/eager FPU context switches
Ever since the kernel started defaulting to eager FPU switches on modern Intel
CPUs it's not been obvious whether a given system is using the lazy or the eager
FPU context switching logic.
So generate a boot message about which mode the FPU code is in:
x86/fpu: Using 'lazy' FPU context switches.
or:
x86/fpu: Using 'eager' FPU context switches.
Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kernel/fpu/xsave.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/xsave.c b/arch/x86/kernel/fpu/xsave.c index a52205b87acb..61696c5005eb 100644 --- a/arch/x86/kernel/fpu/xsave.c +++ b/arch/x86/kernel/fpu/xsave.c @@ -691,6 +691,8 @@ void __init_refok eager_fpu_init(void) if (eagerfpu == ENABLE) setup_force_cpu_cap(X86_FEATURE_EAGER_FPU); + printk_once(KERN_INFO "x86/fpu: Using '%s' FPU context switches.\n", eagerfpu == ENABLE ? "eager" : "lazy"); + if (!cpu_has_eager_fpu) { stts(); return; |