Commit-ID: d8bced79af1db6734f66b42064cc773cada2ce99 Gitweb: http://git.kernel.org/tip/d8bced79af1db6734f66b42064cc773cada2ce99 Author: Andy Lutomirski <[email protected]> AuthorDate: Fri, 29 Jan 2016 11:42:59 -0800 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 9 Feb 2016 13:36:11 +0100
x86/mm: If INVPCID is available, use it to flush global mappings On my Skylake laptop, INVPCID function 2 (flush absolutely everything) takes about 376ns, whereas saving flags, twiddling CR4.PGE to flush global mappings, and restoring flags takes about 539ns. Signed-off-by: Andy Lutomirski <[email protected]> Reviewed-by: Borislav Petkov <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Luis R. Rodriguez <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Toshi Kani <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/ed0ef62581c0ea9c99b9bf6df726015e96d44743.1454096309.git.l...@kernel.org Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/include/asm/tlbflush.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 8b57683..fc9a2fd 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -152,6 +152,15 @@ static inline void __native_flush_tlb_global(void) { unsigned long flags; + if (static_cpu_has(X86_FEATURE_INVPCID)) { + /* + * Using INVPCID is considerably faster than a pair of writes + * to CR4 sandwiched inside an IRQ flag save/restore. + */ + invpcid_flush_all(); + return; + } + /* * Read-modify-write to CR4 - protect it from preemption and * from interrupts. (Use the raw variant because this code can
