mm: cma: add functions to get region pages counters

Here are two functions that provide interface to compute/get used size and
size of biggest free chunk in cma region.  Add that information to
debugfs.

[akpm@linux-foundation.org: move debug code from cma.c into cma_debug.c]
[stefan.strogin@gmail.com: move code from cma_get_used() and cma_get_maxchunk() to cma_used_get() and cma_maxchunk_get()]
Signed-off-by: Dmitry Safonov <d.safonov@partner.samsung.com>
Signed-off-by: Stefan Strogin <stefan.strogin@gmail.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pintu Kumar <pintu.k@samsung.com>
Cc: Weijie Yang <weijie.yang@samsung.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Vyacheslav Tyrtov <v.tyrtov@samsung.com>
Cc: Aleksei Mateosian <a.mateosian@samsung.com>
Signed-off-by: Stefan Strogin <stefan.strogin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/mm/cma_debug.c b/mm/cma_debug.c
index 0b377536ccde..a040bfb132c3 100644
--- a/mm/cma_debug.c
+++ b/mm/cma_debug.c
@@ -33,6 +33,44 @@ static int cma_debugfs_get(void *data, u64 *val)
 
 DEFINE_SIMPLE_ATTRIBUTE(cma_debugfs_fops, cma_debugfs_get, NULL, "%llu\n");
 
+static int cma_used_get(void *data, u64 *val)
+{
+        struct cma *cma = data;
+        unsigned long used;
+
+        mutex_lock(&cma->lock);
+        /* pages counter is smaller than sizeof(int) */
+        used = bitmap_weight(cma->bitmap, (int)cma->count);
+        mutex_unlock(&cma->lock);
+        *val = (u64)used << cma->order_per_bit;
+
+        return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(cma_used_fops, cma_used_get, NULL, "%llu\n");
+
+static int cma_maxchunk_get(void *data, u64 *val)
+{
+        struct cma *cma = data;
+        unsigned long maxchunk = 0;
+        unsigned long start, end = 0;
+
+        mutex_lock(&cma->lock);
+        for (;;) {
+                start = find_next_zero_bit(cma->bitmap, cma->count, end);
+                if (start >= cma->count)
+                        break;
+                end = find_next_bit(cma->bitmap, cma->count, start);
+                maxchunk = max(end - start, maxchunk);
+        }
+        mutex_unlock(&cma->lock);
+        *val = (u64)maxchunk << cma->order_per_bit;
+
+        return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(cma_maxchunk_fops, cma_maxchunk_get, NULL, "%llu\n");
+
 static void cma_add_to_cma_mem_list(struct cma *cma, struct cma_mem *mem)
 {
         spin_lock(&cma->mem_head_lock);
@@ -149,6 +187,8 @@ static void cma_debugfs_add_one(struct cma *cma, int idx)
                                 &cma->count, &cma_debugfs_fops);
         debugfs_create_file("order_per_bit", S_IRUGO, tmp,
                                 &cma->order_per_bit, &cma_debugfs_fops);
+        debugfs_create_file("used", S_IRUGO, tmp, cma, &cma_used_fops);
+        debugfs_create_file("maxchunk", S_IRUGO, tmp, cma, &cma_maxchunk_fops);
 
         u32s = DIV_ROUND_UP(cma_bitmap_maxno(cma), BITS_PER_BYTE * sizeof(u32));
         debugfs_create_u32_array("bitmap", S_IRUGO, tmp, (u32*)cma->bitmap, u32s);