linux-kernel - Re: [v7 PATCH 05/12] mm: memcontrol: rename shrinker_map to shrinker

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Message-ID: <CAHbLzkpX2YCj_cotb7_DpWxQ_cUGAs_iOHxwDSmS1cBxZFR9=A@mail.gmail.com>
Date:   Thu, 11 Feb 2021 09:29:52 -0800
From:   Yang Shi <shy828301@...il.com>
To:     Kirill Tkhai <ktkhai@...tuozzo.com>
Cc:     Roman Gushchin <guro@...com>, Vlastimil Babka <vbabka@...e.cz>,
        Shakeel Butt <shakeelb@...gle.com>,
        Dave Chinner <david@...morbit.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Michal Hocko <mhocko@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linux MM <linux-mm@...ck.org>,
        Linux FS-devel Mailing List <linux-fsdevel@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [v7 PATCH 05/12] mm: memcontrol: rename shrinker_map to shrinker_info

On Thu, Feb 11, 2021 at 8:47 AM Kirill Tkhai <ktkhai@...tuozzo.com> wrote:
>
> On 10.02.2021 02:33, Yang Shi wrote:
> > On Tue, Feb 9, 2021 at 12:50 PM Roman Gushchin <guro@...com> wrote:
> >>
> >> On Tue, Feb 09, 2021 at 09:46:39AM -0800, Yang Shi wrote:
> >>> The following patch is going to add nr_deferred into shrinker_map, the change will
> >>> make shrinker_map not only include map anymore, so rename it to "memcg_shrinker_info".
> >>> And this should make the patch adding nr_deferred cleaner and readable and make
> >>> review easier.  Also remove the "memcg_" prefix.
> >>>
> >>> Acked-by: Vlastimil Babka <vbabka@...e.cz>
> >>> Acked-by: Kirill Tkhai <ktkhai@...tuozzo.com>
> >>> Signed-off-by: Yang Shi <shy828301@...il.com>
> >>> ---
> >>>  include/linux/memcontrol.h |  8 ++---
> >>>  mm/memcontrol.c            |  6 ++--
> >>>  mm/vmscan.c                | 62 +++++++++++++++++++-------------------
> >>>  3 files changed, 38 insertions(+), 38 deletions(-)
> >>>
> >>> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> >>> index 1739f17e0939..4c9253896e25 100644
> >>> --- a/include/linux/memcontrol.h
> >>> +++ b/include/linux/memcontrol.h
> >>> @@ -96,7 +96,7 @@ struct lruvec_stat {
> >>>   * Bitmap of shrinker::id corresponding to memcg-aware shrinkers,
> >>>   * which have elements charged to this memcg.
> >>>   */
> >>> -struct memcg_shrinker_map {
> >>> +struct shrinker_info {
> >>>       struct rcu_head rcu;
> >>>       unsigned long map[];
> >>>  };
> >>> @@ -118,7 +118,7 @@ struct mem_cgroup_per_node {
> >>>
> >>>       struct mem_cgroup_reclaim_iter  iter;
> >>>
> >>> -     struct memcg_shrinker_map __rcu *shrinker_map;
> >>> +     struct shrinker_info __rcu      *shrinker_info;
> >>
> >> Nice!
> >>
> >> I really like how it looks now in comparison to the v1. Thank you for
> >> working on it!
> >
> > Thanks a lot for all the great comments from all of you.
> >
> >>
> >>>
> >>>       struct rb_node          tree_node;      /* RB tree node */
> >>>       unsigned long           usage_in_excess;/* Set to the value by which */
> >>> @@ -1581,8 +1581,8 @@ static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
> >>>       return false;
> >>>  }
> >>>
> >>> -int alloc_shrinker_maps(struct mem_cgroup *memcg);
> >>> -void free_shrinker_maps(struct mem_cgroup *memcg);
> >>> +int alloc_shrinker_info(struct mem_cgroup *memcg);
> >>> +void free_shrinker_info(struct mem_cgroup *memcg);
> >>>  void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id);
> >>>  #else
> >>>  #define mem_cgroup_sockets_enabled 0
> >>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> >>> index f5c9a0d2160b..f64ad0d044d9 100644
> >>> --- a/mm/memcontrol.c
> >>> +++ b/mm/memcontrol.c
> >>> @@ -5246,11 +5246,11 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
> >>>       struct mem_cgroup *memcg = mem_cgroup_from_css(css);
> >>>
> >>>       /*
> >>> -      * A memcg must be visible for expand_shrinker_maps()
> >>> +      * A memcg must be visible for expand_shrinker_info()
> >>>        * by the time the maps are allocated. So, we allocate maps
> >>>        * here, when for_each_mem_cgroup() can't skip it.
> >>>        */
> >>> -     if (alloc_shrinker_maps(memcg)) {
> >>> +     if (alloc_shrinker_info(memcg)) {
> >>>               mem_cgroup_id_remove(memcg);
> >>>               return -ENOMEM;
> >>>       }
> >>> @@ -5314,7 +5314,7 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
> >>>       vmpressure_cleanup(&memcg->vmpressure);
> >>>       cancel_work_sync(&memcg->high_work);
> >>>       mem_cgroup_remove_from_trees(memcg);
> >>> -     free_shrinker_maps(memcg);
> >>> +     free_shrinker_info(memcg);
> >>>       memcg_free_kmem(memcg);
> >>>       mem_cgroup_free(memcg);
> >>>  }
> >>> diff --git a/mm/vmscan.c b/mm/vmscan.c
> >>> index 641077b09e5d..9436f9246d32 100644
> >>> --- a/mm/vmscan.c
> >>> +++ b/mm/vmscan.c
> >>> @@ -190,20 +190,20 @@ static int shrinker_nr_max;
> >>>  #define NR_MAX_TO_SHR_MAP_SIZE(nr_max) \
> >>>       (DIV_ROUND_UP(nr_max, BITS_PER_LONG) * sizeof(unsigned long))
> >>>
> >>> -static void free_shrinker_map_rcu(struct rcu_head *head)
> >>> +static void free_shrinker_info_rcu(struct rcu_head *head)
> >>>  {
> >>> -     kvfree(container_of(head, struct memcg_shrinker_map, rcu));
> >>> +     kvfree(container_of(head, struct shrinker_info, rcu));
> >>>  }
> >>>
> >>> -static int expand_one_shrinker_map(struct mem_cgroup *memcg,
> >>> +static int expand_one_shrinker_info(struct mem_cgroup *memcg,
> >>>                                  int size, int old_size)
> >>>  {
> >>> -     struct memcg_shrinker_map *new, *old;
> >>> +     struct shrinker_info *new, *old;
> >>>       int nid;
> >>>
> >>>       for_each_node(nid) {
> >>>               old = rcu_dereference_protected(
> >>> -                     mem_cgroup_nodeinfo(memcg, nid)->shrinker_map, true);
> >>> +                     mem_cgroup_nodeinfo(memcg, nid)->shrinker_info, true);
> >>>               /* Not yet online memcg */
> >>>               if (!old)
> >>>                       return 0;
> >>> @@ -216,17 +216,17 @@ static int expand_one_shrinker_map(struct mem_cgroup *memcg,
> >>>               memset(new->map, (int)0xff, old_size);
> >>>               memset((void *)new->map + old_size, 0, size - old_size);
> >>>
> >>> -             rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, new);
> >>> -             call_rcu(&old->rcu, free_shrinker_map_rcu);
> >>> +             rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, new);
> >>> +             call_rcu(&old->rcu, free_shrinker_info_rcu);
> >>
> >> Why not use kvfree_rcu() and get rid of free_shrinker_info_rcu() callback?
> >
> > Just because this patch is aimed to rename the structure. I think it
> > may be more preferred to have the cleanup in a separate patch?
>
> I'd voted for a separate patch

Yes, I do agree. Will add a new patch in v8.

>