[PATCH v2 6/6] mm/cma: remove per zone CMA stat

[js1304]

From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

Now, all reserved pages for CMA region are belong to the ZONE_CMA
so we don't need to maintain CMA stat in other zones. Remove it.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
---
 fs/proc/meminfo.c      |  2 +-
 include/linux/cma.h    |  6 ++++++
 include/linux/mmzone.h |  1 -
 mm/cma.c               | 15 +++++++++++++++
 mm/page_alloc.c        |  5 ++---
 mm/vmstat.c            |  1 -
 6 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index ae5cc52..51449d0 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -172,7 +172,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
 #endif
 #ifdef CONFIG_CMA
 		, K(totalcma_pages)
-		, K(global_page_state(NR_FREE_CMA_PAGES))
+		, K(cma_get_free())
 #endif
 		);
 
diff --git a/include/linux/cma.h b/include/linux/cma.h
index 29f9e77..816290c 100644
--- a/include/linux/cma.h
+++ b/include/linux/cma.h
@@ -28,4 +28,10 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 					struct cma **res_cma);
 extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align);
 extern bool cma_release(struct cma *cma, const struct page *pages, unsigned int count);
+
+#ifdef CONFIG_CMA
+extern unsigned long cma_get_free(void);
+#else
+static inline unsigned long cma_get_free(void) { return 0; }
+#endif
 #endif
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 75b41c5..3996a7c 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -140,7 +140,6 @@ enum zone_stat_item {
 	NR_SHMEM_HUGEPAGES,	/* transparent shmem huge pages */
 	NR_SHMEM_PMDMAPPED,	/* shmem huge pages currently mapped hugely */
 	NR_SHMEM_FREEHOLES,	/* unused memory of high-order allocations */
-	NR_FREE_CMA_PAGES,
 	NR_VM_ZONE_STAT_ITEMS };
 
 /*
diff --git a/mm/cma.c b/mm/cma.c
index bd436e4..6dbddf2 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -54,6 +54,21 @@ unsigned long cma_get_size(const struct cma *cma)
 	return cma->count << PAGE_SHIFT;
 }
 
+unsigned long cma_get_free(void)
+{
+	struct zone *zone;
+	unsigned long freecma = 0;
+
+	for_each_populated_zone(zone) {
+		if (!is_zone_cma(zone))
+			continue;
+
+		freecma += zone_page_state(zone, NR_FREE_PAGES);
+	}
+
+	return freecma;
+}
+
 static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
 					     int align_order)
 {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 51b2b0c..570edad 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -63,6 +63,7 @@
 #include <linux/sched/rt.h>
 #include <linux/page_owner.h>
 #include <linux/kthread.h>
+#include <linux/cma.h>
 
 #include <asm/sections.h>
 #include <asm/tlbflush.h>
@@ -4107,7 +4108,7 @@ void show_free_areas(unsigned int filter)
 		global_page_state(NR_SHMEM_FREEHOLES),
 		global_page_state(NR_FREE_PAGES),
 		free_pcp,
-		global_page_state(NR_FREE_CMA_PAGES));
+		cma_get_free());
 
 	for_each_populated_zone(zone) {
 		int i;
@@ -4150,7 +4151,6 @@ void show_free_areas(unsigned int filter)
 			" bounce:%lukB"
 			" free_pcp:%lukB"
 			" local_pcp:%ukB"
-			" free_cma:%lukB"
 			" writeback_tmp:%lukB"
 			" pages_scanned:%lu"
 			" all_unreclaimable? %s"
@@ -4188,7 +4188,6 @@ void show_free_areas(unsigned int filter)
 			K(zone_page_state(zone, NR_BOUNCE)),
 			K(free_pcp),
 			K(this_cpu_read(zone->pageset->pcp.count)),
-			K(zone_page_state(zone, NR_FREE_CMA_PAGES)),
 			K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
 			K(zone_page_state(zone, NR_PAGES_SCANNED)),
 			(!zone_reclaimable(zone) ? "yes" : "no")
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 39a0c3c..81acdae 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -766,7 +766,6 @@ const char * const vmstat_text[] = {
 	"nr_shmem_hugepages",
 	"nr_shmem_pmdmapped",
 	"nr_shmem_freeholes",
-	"nr_free_cma",
 
 	/* enum writeback_stat_item counters */
 	"nr_dirty_threshold",
-- 
1.9.1