On Mon 28-01-13 18:54:30, Jeff Liu wrote:
> Refector swap_cgroup_swapon() to setup the number of pages only, and
> move the rest to swap_cgroup_prepare(), so that the later can be used
> for allocating buffers when creating the first non-root memcg.
>
> Signed-off-by: Jie Liu <jeff.liu@xxxxxxxxxx>
> CC: Glauber Costa <glommer@xxxxxxxxxxxxx>
> CC: Michal Hocko <mhocko@xxxxxxx>
> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> CC: Johannes Weiner <hannes@xxxxxxxxxxx>
> CC: Mel Gorman <mgorman@xxxxxxx>
> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> CC: Sha Zhengju <handai.szj@xxxxxxxxxx>
Makes sense and it even saves some lines.
Acked-by: Michal Hocko <mhocko@xxxxxxx>
>
> ---
> mm/page_cgroup.c | 17 ++++++-----------
> 1 file changed, 6 insertions(+), 11 deletions(-)
>
> diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
> index 6d757e3..c945254 100644
> --- a/mm/page_cgroup.c
> +++ b/mm/page_cgroup.c
> @@ -360,6 +360,9 @@ static int swap_cgroup_prepare(int type)
> unsigned long idx, max;
>
> ctrl = &swap_cgroup_ctrl[type];
> + ctrl->map = vzalloc(ctrl->length * sizeof(void *));
> + if (!ctrl->map)
> + goto nomem;
>
> for (idx = 0; idx < ctrl->length; idx++) {
> page = alloc_page(GFP_KERNEL | __GFP_ZERO);
> @@ -368,11 +371,13 @@ static int swap_cgroup_prepare(int type)
> ctrl->map[idx] = page;
> }
> return 0;
> +
> not_enough_page:
> max = idx;
> for (idx = 0; idx < max; idx++)
> __free_page(ctrl->map[idx]);
> -
> + ctrl->map = NULL;
> +nomem:
> return -ENOMEM;
> }
>
> @@ -460,8 +465,6 @@ unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
>
> int swap_cgroup_swapon(int type, unsigned long max_pages)
> {
> - void *array;
> - unsigned long array_size;
> unsigned long length;
> struct swap_cgroup_ctrl *ctrl;
>
> @@ -469,23 +472,15 @@ int swap_cgroup_swapon(int type, unsigned long max_pages)
> return 0;
>
> length = DIV_ROUND_UP(max_pages, SC_PER_PAGE);
> - array_size = length * sizeof(void *);
> -
> - array = vzalloc(array_size);
> - if (!array)
> - goto nomem;
>
> ctrl = &swap_cgroup_ctrl[type];
> mutex_lock(&swap_cgroup_mutex);
> ctrl->length = length;
> - ctrl->map = array;
> spin_lock_init(&ctrl->lock);
> if (swap_cgroup_prepare(type)) {
> /* memory shortage */
> - ctrl->map = NULL;
> ctrl->length = 0;
> mutex_unlock(&swap_cgroup_mutex);
> - vfree(array);
> goto nomem;
> }
> mutex_unlock(&swap_cgroup_mutex);
> --
> 1.7.9.5
>
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--
Michal Hocko
SUSE Labs
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