On 03/09/2012 11:40 AM, KAMEZAWA Hiroyuki wrote:
On Tue, 6 Mar 2012 20:13:24 +0800
Sha Zhengju<handai.szj@xxxxxxxxx> wrote:
From: Sha Zhengju<handai.szj@xxxxxxxxxx>
When the last event is unregistered, there is no need to keep the spare
array anymore. So free it to avoid memory leak.
Signed-off-by: Sha Zhengju<handai.szj@xxxxxxxxxx>
---
mm/memcontrol.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 22d94f5..3c09a84 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4412,6 +4412,12 @@ static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
swap_buffers:
/* Swap primary and spare array */
thresholds->spare = thresholds->primary;
+ /* If all events are unregistered, free the spare array */
+ if (!new) {
+ kfree(thresholds->spare);
+ thresholds->spare = NULL;
+ }
+
Could you clear thresholds->primary ? I don't like a pointer points to freed memory.
Do you meaning I should set ‘thresholds->primary = NULL‘ ？
But the following rcu_assign_pointer will do this :
+ /* If all events are unregistered, free the spare array */
+ if (!new) {
+ kfree(thresholds->spare);
+ thresholds->spare = NULL;
+ }
+
rcu_assign_pointer(thresholds->primary, new);<---------*HERE*
/* To be sure that nobody uses thresholds */
--
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