From 61350951095522c425510739a96aec105922f37e Mon Sep 17 00:00:00 2001
From: Prakash Gupta <guptap@codeaurora.org>
Date: Wed, 2 Aug 2017 12:30:55 +0530
Subject: [PATCH] mm: cma: Register with show_mem notification framework

Register with the show_mem notification framework
to let cma dump out data for debugging.

This is an example output with this patch.

 cma: cma-0 pages: => 0 used of 2048 total pages
 cma: cma-1 pages: => 0 used of 23552 total pages
 cma: cma-2 pages: => 1696 used of 3072 total pages
 cma: cma-3 pages: => 8277 used of 9216 total pages
 cma: cma-4 pages: => 186 used of 5120 total pages
 cma: cma-5 pages: => 3792 used of 8192 total pages.

Change-Id: I80d9291444fd9361f5586bdf60373ed8b5b41705
Signed-off-by: Prakash Gupta <guptap@codeaurora.org>
[<swatsrid@codeaurora.org: Fix trivial errors in commit text]
Signed-off-by: Swathi Sridhar <swatsrid@codeaurora.org>
[isaacm@codeaurora.org: Fix trivial merge conflicts]
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
---
 mm/cma.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/mm/cma.c b/mm/cma.c
index e7a6f4e511eb..6fdd2fd00bb8 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -34,6 +34,7 @@
 #include <linux/io.h>
 #include <linux/kmemleak.h>
 #include <linux/delay.h>
+#include <linux/show_mem_notifier.h>
 #include <trace/events/cma.h>
 
 #include "cma.h"
@@ -96,6 +97,29 @@ static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
 	mutex_unlock(&cma->lock);
 }
 
+static int cma_showmem_notifier(struct notifier_block *nb,
+				   unsigned long action, void *data)
+{
+	int i;
+	unsigned long used;
+	struct cma *cma;
+
+	for (i = 0; i < cma_area_count; i++) {
+		cma = &cma_areas[i];
+		used = bitmap_weight(cma->bitmap,
+				     (int)cma_bitmap_maxno(cma));
+		used <<= cma->order_per_bit;
+		pr_info("cma-%d pages: => %lu used of %lu total pages\n",
+			i, used, cma->count);
+	}
+
+	return 0;
+}
+
+static struct notifier_block cma_nb = {
+	.notifier_call = cma_showmem_notifier,
+};
+
 static int __init cma_activate_area(struct cma *cma)
 {
 	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
@@ -158,6 +182,8 @@ static int __init cma_init_reserved_areas(void)
 			return ret;
 	}
 
+	show_mem_notifier_register(&cma_nb);
+
 	return 0;
 }
 core_initcall(cma_init_reserved_areas);