Commit-ID: d8bced79af1db6734f66b42064cc773cada2ce99 Gitweb: http://git.kernel.org/tip/d8bced79af1db6734f66b42064cc773cada2ce99 Author: Andy Lutomirski <l...@kernel.org> AuthorDate: Fri, 29 Jan 2016 11:42:59 -0800 Committer: Ingo Molnar <mi...@kernel.org> 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 <l...@kernel.org> Reviewed-by: Borislav Petkov <b...@suse.de> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Andrey Ryabinin <aryabi...@virtuozzo.com> Cc: Andy Lutomirski <l...@amacapital.net> Cc: Borislav Petkov <b...@alien8.de> Cc: Brian Gerst <brge...@gmail.com> Cc: Dave Hansen <dave.han...@linux.intel.com> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Luis R. Rodriguez <mcg...@suse.com> Cc: Oleg Nesterov <o...@redhat.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Toshi Kani <toshi.k...@hp.com> Cc: linux...@kvack.org Link: http://lkml.kernel.org/r/ed0ef62581c0ea9c99b9bf6df726015e96d44743.1454096309.git.l...@kernel.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- 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
