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

[Ying Han <yinghan@google.com>]

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

> On Thu, 14 Apr 2011 15:54:23 -0700
> Ying Han <yinghan@google.com> 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@google.com>
>
>
> > ---
> >  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
>
>

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