From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
Private is vacant for most of Non-LRU pages while the user has explicitly
operation on page->private via set_page_private, I would like introduce
stackdepot information on page->private for a simplified tracking mechanism
which could be help for kernel driver's memory leak.
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
---
mm/page_alloc.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e5486d4..b79a503 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -75,6 +75,7 @@
#include <linux/khugepaged.h>
#include <linux/buffer_head.h>
#include <linux/delayacct.h>
+#include <linux/stackdepot.h>
#include <asm/sections.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -2464,6 +2465,25 @@ static inline bool should_skip_init(gfp_t flags)
return (flags & __GFP_SKIP_ZERO);
}
+#ifdef CONFIG_STACKDEPOT
+static noinline depot_stack_handle_t set_track_prepare(void)
+{
+ depot_stack_handle_t trace_handle;
+ unsigned long entries[16];
+ unsigned int nr_entries;
+
+ nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
+ trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
+
+ return trace_handle;
+}
+#else
+static inline depot_stack_handle_t set_track_prepare(void)
+{
+ return 0;
+}
+#endif
+
inline void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags)
{
@@ -2471,8 +2491,14 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
!should_skip_init(gfp_flags);
bool init_tags = init && (gfp_flags & __GFP_ZEROTAGS);
int i;
+ depot_stack_handle_t stack_handle = set_track_prepare();
- set_page_private(page, 0);
+ /*
+ * Don't worry, user will cover private directly without checking
+ * this field and has ability to trace the page. This also will not
+ * affect expected state when freeing
+ */
+ set_page_private(page, stack_handle);
set_page_refcounted(page);
arch_alloc_page(page, order);
--
1.9.1
