From 7dd80b8af0bcd705a9ef2fa272c082882616a499 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Tue, 15 Mar 2016 14:56:12 -0700 Subject: mm, page_owner: convert page_owner_inited to static key CONFIG_PAGE_OWNER attempts to impose negligible runtime overhead when enabled during compilation, but not actually enabled during runtime by boot param page_owner=on. This overhead can be further reduced using the static key mechanism, which this patch does. Signed-off-by: Vlastimil Babka Acked-by: Michal Hocko Cc: Joonsoo Kim Cc: Minchan Kim Cc: Sasha Levin Cc: "Kirill A. Shutemov" Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_owner.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'mm/page_owner.c') diff --git a/mm/page_owner.c b/mm/page_owner.c index 7a37a30d941b..feaa28b40c1c 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -5,10 +5,11 @@ #include #include #include +#include #include "internal.h" static bool page_owner_disabled = true; -bool page_owner_inited __read_mostly; +DEFINE_STATIC_KEY_FALSE(page_owner_inited); static void init_early_allocated_pages(void); @@ -37,7 +38,7 @@ static void init_page_owner(void) if (page_owner_disabled) return; - page_owner_inited = true; + static_branch_enable(&page_owner_inited); init_early_allocated_pages(); } @@ -147,7 +148,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) struct page *page; struct page_ext *page_ext; - if (!page_owner_inited) + if (!static_branch_unlikely(&page_owner_inited)) return -EINVAL; page = NULL; @@ -295,7 +296,7 @@ static int __init pageowner_init(void) { struct dentry *dentry; - if (!page_owner_inited) { + if (!static_branch_unlikely(&page_owner_inited)) { pr_info("page_owner is disabled\n"); return 0; } -- cgit v1.2.3