Re: [PATCH V4 04/10] Infrastructure to support per-memcg reclaim.

[Ying Han <yinghan@xxxxxxxxxx>]

On Thu, Apr 14, 2011 at 5:34 PM, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:

On Thu, 14 Apr 2011 15:54:23 -0700
Ying Han <yinghan@xxxxxxxxxx> wrote:

> Add the kswapd_mem field in kswapd descriptor which links the kswapd
> kernel thread to a memcg. The per-memcg kswapd is sleeping in the wait
> queue headed at kswapd_wait field of the kswapd descriptor.
>
> The kswapd() function is now shared between global and per-memcg kswapd. It
> is passed in with the kswapd descriptor which contains the information of
> either node or memcg. Then the new function balance_mem_cgroup_pgdat is
> invoked if it is per-mem kswapd thread, and the implementation of the function
> is on the following patch.
>
> changelog v4..v3:
> 1. fix up the kswapd_run and kswapd_stop for online_pages() and offline_pages.
> 2. drop the PF_MEMALLOC flag for memcg kswapd for now per KAMAZAWA's request.
>
> changelog v3..v2:
> 1. split off from the initial patch which includes all changes of the following
> three patches.
>
> Signed-off-by: Ying Han <yinghan@xxxxxxxxxx>


> ---
>  include/linux/memcontrol.h |    5 ++
>  include/linux/swap.h       |    5 +-
>  mm/memcontrol.c            |   29 ++++++++
>  mm/memory_hotplug.c        |    4 +-
>  mm/vmscan.c                |  157 ++++++++++++++++++++++++++++++--------------
>  5 files changed, 147 insertions(+), 53 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 3ece36d..f7ffd1f 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -24,6 +24,7 @@ struct mem_cgroup;
>  struct page_cgroup;
>  struct page;
>  struct mm_struct;
> +struct kswapd;
>
>  /* Stats that can be updated by kernel. */
>  enum mem_cgroup_page_stat_item {
> @@ -83,6 +84,10 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
>  extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
>  extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
>  extern int mem_cgroup_watermark_ok(struct mem_cgroup *mem, int charge_flags);
> +extern int mem_cgroup_init_kswapd(struct mem_cgroup *mem,
> +                               struct kswapd *kswapd_p);
> +extern void mem_cgroup_clear_kswapd(struct mem_cgroup *mem);
> +extern wait_queue_head_t *mem_cgroup_kswapd_wait(struct mem_cgroup *mem);
>
>  static inline
>  int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index f43d406..17e0511 100644
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -30,6 +30,7 @@ struct kswapd {
>       struct task_struct *kswapd_task;
>       wait_queue_head_t kswapd_wait;
>       pg_data_t *kswapd_pgdat;
> +     struct mem_cgroup *kswapd_mem;
>  };
>
>  int kswapd(void *p);
> @@ -303,8 +304,8 @@ static inline void scan_unevictable_unregister_node(struct node *node)
>  }
>  #endif
>
> -extern int kswapd_run(int nid);
> -extern void kswapd_stop(int nid);
> +extern int kswapd_run(int nid, struct mem_cgroup *mem);
> +extern void kswapd_stop(int nid, struct mem_cgroup *mem);
>
>  #ifdef CONFIG_MMU
>  /* linux/mm/shmem.c */
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 685645c..c4e1904 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -278,6 +278,8 @@ struct mem_cgroup {
>        */
>       u64 high_wmark_distance;
>       u64 low_wmark_distance;
> +
> +     wait_queue_head_t *kswapd_wait;
>  };

I think mem_cgroup can include 'struct kswapd' itself and don't need to
alloc it dynamically.

Other parts seems ok to me.

The same for the previous post. I would like to keep the implementation for the first version if not one is strongly better than the other. Hope that works.

--Ying

Thanks,
-Kame