From 44bf431b47b4298d8aaba7b02d0ad29fc609a03c Mon Sep 17 00:00:00 2001 From: Bibo Mao Date: Wed, 27 May 2020 10:25:19 +0800 Subject: mm/memory.c: Add memory read privilege on page fault handling Here add pte_sw_mkyoung function to make page readable on MIPS platform during page fault handling. This patch improves page fault latency about 10% on my MIPS machine with lmbench lat_pagefault case. It is noop function on other arches, there is no negative influence on those architectures. Signed-off-by: Bibo Mao Acked-by: Andrew Morton Signed-off-by: Thomas Bogendoerfer --- include/asm-generic/pgtable.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include') diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index fa5c73ff8226..b5278ec627db 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -244,6 +244,22 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres } #endif +/* + * On some architectures hardware does not set page access bit when accessing + * memory page, it is responsibilty of software setting this bit. It brings + * out extra page fault penalty to track page access bit. For optimization page + * access bit can be set during all page fault flow on these arches. + * To be differentiate with macro pte_mkyoung, this macro is used on platforms + * where software maintains page access bit. + */ +#ifndef pte_sw_mkyoung +static inline pte_t pte_sw_mkyoung(pte_t pte) +{ + return pte; +} +#define pte_sw_mkyoung pte_sw_mkyoung +#endif + #ifndef pte_savedwrite #define pte_savedwrite pte_write #endif -- cgit v1.2.3