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>

14 files changed, 20 insertions, 20 deletions

diff --git a/drivers/char/agp/backend.c b/drivers/char/agp/backend.c
index 38ffb281df97..004a3ce8ba72 100644
--- a/drivers/char/agp/backend.c
+++ b/drivers/char/agp/backend.c
@@ -115,9 +115,9 @@ static int agp_find_max(void)
 	long memory, index, result;
 
 #if PAGE_SHIFT < 20
-	memory = totalram_pages >> (20 - PAGE_SHIFT);
+	memory = totalram_pages() >> (20 - PAGE_SHIFT);
 #else
-	memory = totalram_pages << (PAGE_SHIFT - 20);
+	memory = totalram_pages() << (PAGE_SHIFT - 20);
 #endif
 	index = 1;
 
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d36a9755ad91..a9de07bb72c8 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2559,7 +2559,7 @@ static int i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
 	 * If there's no chance of allocating enough pages for the whole
 	 * object, bail early.
 	 */
-	if (page_count > totalram_pages)
+	if (page_count > totalram_pages())
 		return -ENOMEM;
 
 	st = kmalloc(sizeof(*st), GFP_KERNEL);
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index 69fe86b30fbb..a9ed0ecc94e2 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -170,7 +170,7 @@ static int igt_ppgtt_alloc(void *arg)
 	 * This should ensure that we do not run into the oomkiller during
 	 * the test and take down the machine wilfully.
 	 */
-	limit = totalram_pages << PAGE_SHIFT;
+	limit = totalram_pages() << PAGE_SHIFT;
 	limit = min(ppgtt->vm.total, limit);
 
 	/* Check we can allocate the entire range */
@@ -1244,7 +1244,7 @@ static int exercise_mock(struct drm_i915_private *i915,
 				     u64 hole_start, u64 hole_end,
 				     unsigned long end_time))
 {
-	const u64 limit = totalram_pages << PAGE_SHIFT;
+	const u64 limit = totalram_pages() << PAGE_SHIFT;
 	struct i915_gem_context *ctx;
 	struct i915_hw_ppgtt *ppgtt;
 	IGT_TIMEOUT(end_time);
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index f3e7da981610..5301fef16c31 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -1090,7 +1090,7 @@ static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg)
 static unsigned long compute_balloon_floor(void)
 {
 	unsigned long min_pages;
-	unsigned long nr_pages = totalram_pages;
+	unsigned long nr_pages = totalram_pages();
 #define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT))
 	/* Simple continuous piecewiese linear function:
 	 *  max MiB -> min MiB  gradient
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index dc385b70e4c3..8b0b628e5d1c 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -1887,7 +1887,7 @@ static int __init dm_bufio_init(void)
 	dm_bufio_allocated_vmalloc = 0;
 	dm_bufio_current_allocated = 0;
 
-	mem = (__u64)mult_frac(totalram_pages - totalhigh_pages,
+	mem = (__u64)mult_frac(totalram_pages() - totalhigh_pages(),
 			       DM_BUFIO_MEMORY_PERCENT, 100) << PAGE_SHIFT;
 
 	if (mem > ULONG_MAX)
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index a7195eb5b8d8..a8c32de29e3f 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2158,7 +2158,7 @@ static int crypt_wipe_key(struct crypt_config *cc)
 
 static void crypt_calculate_pages_per_client(void)
 {
-	unsigned long pages = (totalram_pages - totalhigh_pages) * DM_CRYPT_MEMORY_PERCENT / 100;
+	unsigned long pages = (totalram_pages() - totalhigh_pages()) * DM_CRYPT_MEMORY_PERCENT / 100;
 
 	if (!dm_crypt_clients_n)
 		return;
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index d4ad0bfee251..62baa3214cc7 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -2843,7 +2843,7 @@ static int create_journal(struct dm_integrity_c *ic, char **error)
 	journal_pages = roundup((__u64)ic->journal_sections * ic->journal_section_sectors,
 				PAGE_SIZE >> SECTOR_SHIFT) >> (PAGE_SHIFT - SECTOR_SHIFT);
 	journal_desc_size = journal_pages * sizeof(struct page_list);
-	if (journal_pages >= totalram_pages - totalhigh_pages || journal_desc_size > ULONG_MAX) {
+	if (journal_pages >= totalram_pages() - totalhigh_pages() || journal_desc_size > ULONG_MAX) {
 		*error = "Journal doesn't fit into memory";
 		r = -ENOMEM;
 		goto bad;
diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c
index 21de30b4e2a1..45b92a3d9d8e 100644
--- a/drivers/md/dm-stats.c
+++ b/drivers/md/dm-stats.c
@@ -85,7 +85,7 @@ static bool __check_shared_memory(size_t alloc_size)
 	a = shared_memory_amount + alloc_size;
 	if (a < shared_memory_amount)
 		return false;
-	if (a >> PAGE_SHIFT > totalram_pages / DM_STATS_MEMORY_FACTOR)
+	if (a >> PAGE_SHIFT > totalram_pages() / DM_STATS_MEMORY_FACTOR)
 		return false;
 #ifdef CONFIG_MMU
 	if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR)
diff --git a/drivers/media/platform/mtk-vpu/mtk_vpu.c b/drivers/media/platform/mtk-vpu/mtk_vpu.c
index 616f78b24a79..b6602490a247 100644
--- a/drivers/media/platform/mtk-vpu/mtk_vpu.c
+++ b/drivers/media/platform/mtk-vpu/mtk_vpu.c
@@ -855,7 +855,7 @@ static int mtk_vpu_probe(struct platform_device *pdev)
 	/* Set PTCM to 96K and DTCM to 32K */
 	vpu_cfg_writel(vpu, 0x2, VPU_TCM_CFG);
 
-	vpu->enable_4GB = !!(totalram_pages > (SZ_2G >> PAGE_SHIFT));
+	vpu->enable_4GB = !!(totalram_pages() > (SZ_2G >> PAGE_SHIFT));
 	dev_info(dev, "4GB mode %u\n", vpu->enable_4GB);
 
 	if (vpu->enable_4GB) {
diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index 9b0b3fa4f836..e6126a4b95d3 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -570,7 +570,7 @@ static int vmballoon_send_get_target(struct vmballoon *b)
 	unsigned long status;
 	unsigned long limit;
 
-	limit = totalram_pages;
+	limit = totalram_pages();
 
 	/* Ensure limit fits in 32-bits */
 	if (limit != (u32)limit)
diff --git a/drivers/parisc/ccio-dma.c b/drivers/parisc/ccio-dma.c
index 701a7d6a74d5..358e380eb7fa 100644
--- a/drivers/parisc/ccio-dma.c
+++ b/drivers/parisc/ccio-dma.c
@@ -1251,7 +1251,7 @@ ccio_ioc_init(struct ioc *ioc)
 	** Hot-Plug/Removal of PCI cards. (aka PCI OLARD).
 	*/
 
-	iova_space_size = (u32) (totalram_pages / count_parisc_driver(&ccio_driver));
+	iova_space_size = (u32) (totalram_pages() / count_parisc_driver(&ccio_driver));
 
 	/* limit IOVA space size to 1MB-1GB */
 
@@ -1290,7 +1290,7 @@ ccio_ioc_init(struct ioc *ioc)
 
 	DBG_INIT("%s() hpa 0x%p mem %luMB IOV %dMB (%d bits)\n",
 			__func__, ioc->ioc_regs,
-			(unsigned long) totalram_pages >> (20 - PAGE_SHIFT),
+			(unsigned long) totalram_pages() >> (20 - PAGE_SHIFT),
 			iova_space_size>>20,
 			iov_order + PAGE_SHIFT);
 
diff --git a/drivers/parisc/sba_iommu.c b/drivers/parisc/sba_iommu.c
index c1e599a429af..e0655949480a 100644
--- a/drivers/parisc/sba_iommu.c
+++ b/drivers/parisc/sba_iommu.c
@@ -1414,7 +1414,7 @@ sba_ioc_init(struct parisc_device *sba, struct ioc *ioc, int ioc_num)
 	** for DMA hints - ergo only 30 bits max.
 	*/
 
-	iova_space_size = (u32) (totalram_pages/global_ioc_cnt);
+	iova_space_size = (u32) (totalram_pages()/global_ioc_cnt);
 
 	/* limit IOVA space size to 1MB-1GB */
 	if (iova_space_size < (1 << (20 - PAGE_SHIFT))) {
@@ -1439,7 +1439,7 @@ sba_ioc_init(struct parisc_device *sba, struct ioc *ioc, int ioc_num)
 	DBG_INIT("%s() hpa 0x%lx mem %ldMB IOV %dMB (%d bits)\n",
 			__func__,
 			ioc->ioc_hpa,
-			(unsigned long) totalram_pages >> (20 - PAGE_SHIFT),
+			(unsigned long) totalram_pages() >> (20 - PAGE_SHIFT),
 			iova_space_size>>20,
 			iov_order + PAGE_SHIFT);
 
diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
index 548bb02c0ca6..6cb0eebdff89 100644
--- a/drivers/staging/android/ion/ion_system_heap.c
+++ b/drivers/staging/android/ion/ion_system_heap.c
@@ -110,7 +110,7 @@ static int ion_system_heap_allocate(struct ion_heap *heap,
 	unsigned long size_remaining = PAGE_ALIGN(size);
 	unsigned int max_order = orders[0];
 
-	if (size / PAGE_SIZE > totalram_pages / 2)
+	if (size / PAGE_SIZE > totalram_pages() / 2)
 		return -ENOMEM;
 
 	INIT_LIST_HEAD(&pages);
diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c
index 5165aa82bf7d..246f6122c9ee 100644
--- a/drivers/xen/xen-selfballoon.c
+++ b/drivers/xen/xen-selfballoon.c
@@ -189,7 +189,7 @@ static void selfballoon_process(struct work_struct *work)
 	bool reset_timer = false;
 
 	if (xen_selfballooning_enabled) {
-		cur_pages = totalram_pages;
+		cur_pages = totalram_pages();
 		tgt_pages = cur_pages; /* default is no change */
 		goal_pages = vm_memory_committed() +
 				totalreserve_pages +
@@ -227,7 +227,7 @@ static void selfballoon_process(struct work_struct *work)
 		if (tgt_pages < floor_pages)
 			tgt_pages = floor_pages;
 		balloon_set_new_target(tgt_pages +
-			balloon_stats.current_pages - totalram_pages);
+			balloon_stats.current_pages - totalram_pages());
 		reset_timer = true;
 	}
 #ifdef CONFIG_FRONTSWAP
@@ -569,7 +569,7 @@ int xen_selfballoon_init(bool use_selfballooning, bool use_frontswap_selfshrink)
 	 * much more reliably and response faster in some cases.
 	 */
 	if (!selfballoon_reserved_mb) {
-		reserve_pages = totalram_pages / 10;
+		reserve_pages = totalram_pages() / 10;
 		selfballoon_reserved_mb = PAGES2MB(reserve_pages);
 	}
 	schedule_delayed_work(&selfballoon_worker, selfballoon_interval * HZ);