On 04/12/2012 08:20 AM, KAMEZAWA Hiroyuki wrote:
>
> This function is used for moving accounting information to its
> parent in the hierarchy of res_counter.
>
> Signed-off-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@xxxxxxxxxxxxxx>
Frederic has a patch in his fork cgroup series, that allows you to
uncharge a counter until you reach a specific ancestor.
You pass the parent as a parameter, and then only you gets uncharged.
I think that is a much better interface than this you are proposing.
We should probably merge that patch and use it.
> ---
> include/linux/res_counter.h | 3 +++
> kernel/res_counter.c | 13 +++++++++++++
> 2 files changed, 16 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
> index da81af0..8919d3c 100644
> --- a/include/linux/res_counter.h
> +++ b/include/linux/res_counter.h
> @@ -135,6 +135,9 @@ int __must_check res_counter_charge_nofail(struct res_counter *counter,
> void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
> void res_counter_uncharge(struct res_counter *counter, unsigned long val);
>
> +/* move resource to parent counter...i.e. just forget accounting in a child */
> +void res_counter_move_parent(struct res_counter *counter, unsigned long val);
> +
> /**
> * res_counter_margin - calculate chargeable space of a counter
> * @cnt: the counter
> diff --git a/kernel/res_counter.c b/kernel/res_counter.c
> index d508363..fafebf0 100644
> --- a/kernel/res_counter.c
> +++ b/kernel/res_counter.c
> @@ -113,6 +113,19 @@ void res_counter_uncharge(struct res_counter *counter, unsigned long val)
> local_irq_restore(flags);
> }
>
> +/*
> + * In hierarchical accounting, child's usage is accounted into ancestors.
> + * To move local usage to its parent, just forget current level usage.
> + */
> +void res_counter_move_parent(struct res_counter *counter, unsigned long val)
> +{
> + unsigned long flags;
> +
> + BUG_ON(!counter->parent);
> + spin_lock_irqsave(&counter->lock, flags);
> + res_counter_uncharge_locked(counter, val);
> + spin_unlock_irqrestore(&counter->lock, flags);
> +}
>
> static inline unsigned long long *
> res_counter_member(struct res_counter *counter, int member)
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