From ca79b0c211af63fa3276f0e3fd7dd9ada2439839 Mon Sep 17 00:00:00 2001 From: Arun KS Date: Fri, 28 Dec 2018 00:34:29 -0800 Subject: mm: convert totalram_pages and totalhigh_pages variables to atomic totalram_pages and totalhigh_pages are made static inline function. Main motivation was that managed_page_count_lock handling was complicating things. It was discussed in length here, https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes better to remove the lock and convert variables to atomic, with preventing poteintial store-to-read tearing as a bonus. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS Suggested-by: Michal Hocko Suggested-by: Vlastimil Babka Reviewed-by: Konstantin Khlebnikov Reviewed-by: Pavel Tatashin Acked-by: Michal Hocko Acked-by: Vlastimil Babka Cc: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/highmem.h | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-) (limited to 'include/linux/highmem.h') diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 0690679832d4..ea5cdbd8c2c3 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -36,7 +36,31 @@ static inline void invalidate_kernel_vmap_range(void *vaddr, int size) /* declarations for linux/mm/highmem.c */ unsigned int nr_free_highpages(void); -extern unsigned long totalhigh_pages; +extern atomic_long_t _totalhigh_pages; +static inline unsigned long totalhigh_pages(void) +{ + return (unsigned long)atomic_long_read(&_totalhigh_pages); +} + +static inline void totalhigh_pages_inc(void) +{ + atomic_long_inc(&_totalhigh_pages); +} + +static inline void totalhigh_pages_dec(void) +{ + atomic_long_dec(&_totalhigh_pages); +} + +static inline void totalhigh_pages_add(long count) +{ + atomic_long_add(count, &_totalhigh_pages); +} + +static inline void totalhigh_pages_set(long val) +{ + atomic_long_set(&_totalhigh_pages, val); +} void kmap_flush_unused(void); @@ -51,7 +75,7 @@ static inline struct page *kmap_to_page(void *addr) return virt_to_page(addr); } -#define totalhigh_pages 0UL +static inline unsigned long totalhigh_pages(void) { return 0UL; } #ifndef ARCH_HAS_KMAP static inline void *kmap(struct page *page) -- cgit v1.2.3