On Fri, 09 Mar 2012 12:07:32 +0800
Sha Zhengju <handai.szj@xxxxxxxxx> wrote:
> 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*
>
Hm, ok.
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
BTW, can memory cgroup be destroyed while there are registered events ?
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