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>

7 files changed, 7 insertions, 7 deletions

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 79a265ba9200..dfb64a5211b6 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -810,7 +810,7 @@ static inline int default_congestion_kb(void)
          * This allows larger machines to have larger/more transfers.
          * Limit the default to 256M
          */
-        congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
+        congestion_kb = (16*int_sqrt(totalram_pages())) << (PAGE_SHIFT-10);
         if (congestion_kb > 256*1024)
                 congestion_kb = 256*1024;
 
diff --git a/fs/file_table.c b/fs/file_table.c
index b6e9587f05c7..5679e7fcb6b0 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -380,7 +380,7 @@ void __init files_init(void)
 void __init files_maxfiles_init(void)
 {
         unsigned long n;
-        unsigned long nr_pages = totalram_pages;
+        unsigned long nr_pages = totalram_pages();
         unsigned long memreserve = (nr_pages - nr_free_pages()) * 3/2;
 
         memreserve = min(memreserve, nr_pages - 1);
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 568abed20eb2..76baaa6be393 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -824,7 +824,7 @@ static const struct super_operations fuse_super_operations = {
 static void sanitize_global_limit(unsigned *limit)
 {
         if (*limit == 0)
-                *limit = ((totalram_pages << PAGE_SHIFT) >> 13) /
+                *limit = ((totalram_pages() << PAGE_SHIFT) >> 13) /
                          sizeof(struct fuse_req);
 
         if (*limit >= 1 << 16)
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 586726a590d8..4f15665f0ad1 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -2121,7 +2121,7 @@ int __init nfs_init_writepagecache(void)
          * This allows larger machines to have larger/more transfers.
          * Limit the default to 256M
          */
-        nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
+        nfs_congestion_kb = (16*int_sqrt(totalram_pages())) << (PAGE_SHIFT-10);
         if (nfs_congestion_kb > 256*1024)
                 nfs_congestion_kb = 256*1024;
 
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index e2fe0e9ce0df..da52b594362a 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -99,7 +99,7 @@ static unsigned int
 nfsd_cache_size_limit(void)
 {
         unsigned int limit;
-        unsigned long low_pages = totalram_pages - totalhigh_pages;
+        unsigned long low_pages = totalram_pages() - totalhigh_pages();
 
         limit = (16 * int_sqrt(low_pages)) << (PAGE_SHIFT-10);
         return min_t(unsigned int, limit, 256*1024);
diff --git a/fs/ntfs/malloc.h b/fs/ntfs/malloc.h
index ab172e5f51d9..5becc8acc8f4 100644
--- a/fs/ntfs/malloc.h
+++ b/fs/ntfs/malloc.h
@@ -47,7 +47,7 @@ static inline void *__ntfs_malloc(unsigned long size, gfp_t gfp_mask)
                 return kmalloc(PAGE_SIZE, gfp_mask & ~__GFP_HIGHMEM);
                 /* return (void *)__get_free_page(gfp_mask); */
         }
-        if (likely((size >> PAGE_SHIFT) < totalram_pages))
+        if (likely((size >> PAGE_SHIFT) < totalram_pages()))
                 return __vmalloc(size, gfp_mask, PAGE_KERNEL);
         return NULL;
 }
diff --git a/fs/proc/base.c b/fs/proc/base.c
index ce3465479447..d7fd1ca807d2 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -530,7 +530,7 @@ static const struct file_operations proc_lstats_operations = {
 static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
                           struct pid *pid, struct task_struct *task)
 {
-        unsigned long totalpages = totalram_pages + total_swap_pages;
+        unsigned long totalpages = totalram_pages() + total_swap_pages;
         unsigned long points = 0;
 
         points = oom_badness(task, NULL, NULL, totalpages) *