summaryrefslogtreecommitdiff
path: root/include/linux/highmem.h
diff options
context:
space:
mode:
authorArun KS <arunks@codeaurora.org>2018-12-28 00:34:29 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 12:11:47 -0800
commitca79b0c211af63fa3276f0e3fd7dd9ada2439839 (patch)
treea9198e85582744619903c85349583bb453fe36cb /include/linux/highmem.h
parent9705bea5f833f4fc21d5bef5fce7348427f76ea4 (diff)
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 <arunks@codeaurora.org> Suggested-by: Michal Hocko <mhocko@suse.com> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/highmem.h')
-rw-r--r--include/linux/highmem.h28
1 files changed, 26 insertions, 2 deletions
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)