From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934513AbdDZS2T (ORCPT ); Wed, 26 Apr 2017 14:28:19 -0400 Received: from mail-lf0-f68.google.com ([209.85.215.68]:36734 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934377AbdDZS2L (ORCPT ); Wed, 26 Apr 2017 14:28:11 -0400 Date: Wed, 26 Apr 2017 21:28:06 +0300 From: Alexey Dobriyan To: x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com Cc: linux-kernel@vger.kernel.org Subject: [PATCH 2/5] x86_64: inline copy_page() at call site Message-ID: <20170426182806.GB5069@avx2> References: <20170426182318.GA5069@avx2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170426182318.GA5069@avx2> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Avoid unconditional branch at every copy_page() call by using alternatives and calling optimal variant directly. Rename individual versions to immediately show which one is used in profiles, etc. RBX and R12 aren't clobbered because generic version restores them and both REP versions don't touch them. Signed-off-by: Alexey Dobriyan --- arch/x86/include/asm/page_64.h | 16 ++++++++++++++-- arch/x86/lib/copy_page_64.S | 17 +++++++---------- 2 files changed, 21 insertions(+), 12 deletions(-) --- a/arch/x86/include/asm/page_64.h +++ b/arch/x86/include/asm/page_64.h @@ -49,8 +49,20 @@ static inline void clear_page(void *page) : "memory", "rax", "rcx"); } -void copy_page(void *to, void *from); - +void copy_page_mov(void *to, void *from); +void copy_page_rep_movsq(void *to, void *from); +void copy_page_rep_movsb(void *to, void *from); +static __always_inline void copy_page(void *to, void *from) +{ + alternative_call_2( + copy_page_mov, + copy_page_rep_movsq, X86_FEATURE_REP_GOOD, + copy_page_rep_movsb, X86_FEATURE_ERMS, + ASM_OUTPUT2("=D" (to), "=S" (from)), + "0" (to), "1" (from) + : "rax", "rcx", "rdx", "r8", "r9", "r10", "r11", "cc", "memory" + ); +} #endif /* !__ASSEMBLY__ */ #ifdef CONFIG_X86_VSYSCALL_EMULATION --- a/arch/x86/lib/copy_page_64.S +++ b/arch/x86/lib/copy_page_64.S @@ -1,8 +1,6 @@ /* Written 2003 by Andi Kleen, based on a kernel by Evandro Menezes */ #include -#include -#include #include /* @@ -12,23 +10,21 @@ * prefetch distance based on SMP/UP. */ ALIGN -ENTRY(copy_page) - ALTERNATIVE_2 "jmp copy_page_regs", \ - "", X86_FEATURE_REP_GOOD, \ - "jmp copy_page_rep_movsb", X86_FEATURE_ERMS +ENTRY(copy_page_rep_movsq) movl $4096/8, %ecx rep movsq ret -ENDPROC(copy_page) -EXPORT_SYMBOL(copy_page) +ENDPROC(copy_page_rep_movsq) +EXPORT_SYMBOL(copy_page_rep_movsq) ENTRY(copy_page_rep_movsb) mov $4096, %ecx rep movsb ret ENDPROC(copy_page_rep_movsb) +EXPORT_SYMBOL(copy_page_rep_movsb) -ENTRY(copy_page_regs) +ENTRY(copy_page_mov) subq $2*8, %rsp movq %rbx, (%rsp) movq %r12, 1*8(%rsp) @@ -93,4 +89,5 @@ ENTRY(copy_page_regs) movq 1*8(%rsp), %r12 addq $2*8, %rsp ret -ENDPROC(copy_page_regs) +ENDPROC(copy_page_mov) +EXPORT_SYMBOL(copy_page_mov)