mm: accurately document nr_free_*_pages functions with code comments
nr_free_zone_pages(), nr_free_buffer_pages() and nr_free_pagecache_pages()
are horribly badly named, so accurately document them with code comments
in case of the misuse of them.
[akpm@linux-foundation.org: tweak comments]
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2761406..e9075fd 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2813,6 +2813,15 @@
}
EXPORT_SYMBOL(free_pages_exact);
+/**
+ * nr_free_zone_pages - count number of pages beyond high watermark
+ * @offset: The zone index of the highest zone
+ *
+ * nr_free_zone_pages() counts the number of counts pages which are beyond the
+ * high watermark within all zones at or below a given zone index. For each
+ * zone, the number of pages is calculated as:
+ * present_pages - high_pages
+ */
static unsigned long nr_free_zone_pages(int offset)
{
struct zoneref *z;
@@ -2833,8 +2842,11 @@
return sum;
}
-/*
- * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
+/**
+ * nr_free_buffer_pages - count number of pages beyond high watermark
+ *
+ * nr_free_buffer_pages() counts the number of pages which are beyond the high
+ * watermark within ZONE_DMA and ZONE_NORMAL.
*/
unsigned long nr_free_buffer_pages(void)
{
@@ -2842,8 +2854,11 @@
}
EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
-/*
- * Amount of free RAM allocatable within all zones
+/**
+ * nr_free_pagecache_pages - count number of pages beyond high watermark
+ *
+ * nr_free_pagecache_pages() counts the number of pages which are beyond the
+ * high watermark within all zones.
*/
unsigned long nr_free_pagecache_pages(void)
{