diff mbox series

[v5,10/11] mm: memcontrol: reparent nr_deferred when memcg offline

Message ID 20210127233345.339910-11-shy828301@gmail.com (mailing list archive)
State New
Headers show
Series Make shrinker's nr_deferred memcg aware | expand

Commit Message

Yang Shi Jan. 27, 2021, 11:33 p.m. UTC
Now shrinker's nr_deferred is per memcg for memcg aware shrinkers, add to parent's
corresponding nr_deferred when memcg offline.

Signed-off-by: Yang Shi <shy828301@gmail.com>
---
 include/linux/memcontrol.h |  1 +
 mm/memcontrol.c            |  1 +
 mm/vmscan.c                | 31 +++++++++++++++++++++++++++++++
 3 files changed, 33 insertions(+)

Comments

Vlastimil Babka Jan. 29, 2021, 3:52 p.m. UTC | #1
On 1/28/21 12:33 AM, Yang Shi wrote:
> Now shrinker's nr_deferred is per memcg for memcg aware shrinkers, add to parent's
> corresponding nr_deferred when memcg offline.
> 
> Signed-off-by: Yang Shi <shy828301@gmail.com>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

A question somewhat outside of the scope of the series. Should we shrink before
reparenting on memcg offline? Would it make more sense than assume the kmemcg
objects that are still cached are used also by others?

> ---
>  include/linux/memcontrol.h |  1 +
>  mm/memcontrol.c            |  1 +
>  mm/vmscan.c                | 31 +++++++++++++++++++++++++++++++
>  3 files changed, 33 insertions(+)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index e0384367e07d..fe1375f08881 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -1586,6 +1586,7 @@ extern int alloc_shrinker_info(struct mem_cgroup *memcg);
>  extern void free_shrinker_info(struct mem_cgroup *memcg);
>  extern void set_shrinker_bit(struct mem_cgroup *memcg,
>  			     int nid, int shrinker_id);
> +extern void reparent_shrinker_deferred(struct mem_cgroup *memcg);
>  #else
>  #define mem_cgroup_sockets_enabled 0
>  static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index f64ad0d044d9..21f36b73f36a 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -5282,6 +5282,7 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
>  	page_counter_set_low(&memcg->memory, 0);
>  
>  	memcg_offline_kmem(memcg);
> +	reparent_shrinker_deferred(memcg);
>  	wb_memcg_offline(memcg);
>  
>  	drain_all_stock(memcg);
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 0373d7619d7b..55ad91a26ba3 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -386,6 +386,37 @@ static long set_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
>  	return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]);
>  }
>  
> +static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
> +						     int nid)
> +{
> +	return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
> +					 lockdep_is_held(&shrinker_rwsem));
> +}
> +
> +void reparent_shrinker_deferred(struct mem_cgroup *memcg)
> +{
> +	int i, nid;
> +	long nr;
> +	struct mem_cgroup *parent;
> +	struct shrinker_info *child_info, *parent_info;
> +
> +	parent = parent_mem_cgroup(memcg);
> +	if (!parent)
> +		parent = root_mem_cgroup;
> +
> +	/* Prevent from concurrent shrinker_info expand */
> +	down_read(&shrinker_rwsem);
> +	for_each_node(nid) {
> +		child_info = shrinker_info_protected(memcg, nid);
> +		parent_info = shrinker_info_protected(parent, nid);
> +		for (i = 0; i < shrinker_nr_max; i++) {
> +			nr = atomic_long_read(&child_info->nr_deferred[i]);
> +			atomic_long_add(nr, &parent_info->nr_deferred[i]);
> +		}
> +	}
> +	up_read(&shrinker_rwsem);
> +}
> +
>  static bool cgroup_reclaim(struct scan_control *sc)
>  {
>  	return sc->target_mem_cgroup;
>
Yang Shi Jan. 29, 2021, 5:38 p.m. UTC | #2
On Fri, Jan 29, 2021 at 7:52 AM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> On 1/28/21 12:33 AM, Yang Shi wrote:
> > Now shrinker's nr_deferred is per memcg for memcg aware shrinkers, add to parent's
> > corresponding nr_deferred when memcg offline.
> >
> > Signed-off-by: Yang Shi <shy828301@gmail.com>
>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
>
> A question somewhat outside of the scope of the series. Should we shrink before
> reparenting on memcg offline? Would it make more sense than assume the kmemcg
> objects that are still cached are used also by others?

TBH, I'm not sure. I think it depends on workload. For example, the
build server may prefer to keep the objects cached since the samce
objects may be reused by multiple build jobs.

>
> > ---
> >  include/linux/memcontrol.h |  1 +
> >  mm/memcontrol.c            |  1 +
> >  mm/vmscan.c                | 31 +++++++++++++++++++++++++++++++
> >  3 files changed, 33 insertions(+)
> >
> > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> > index e0384367e07d..fe1375f08881 100644
> > --- a/include/linux/memcontrol.h
> > +++ b/include/linux/memcontrol.h
> > @@ -1586,6 +1586,7 @@ extern int alloc_shrinker_info(struct mem_cgroup *memcg);
> >  extern void free_shrinker_info(struct mem_cgroup *memcg);
> >  extern void set_shrinker_bit(struct mem_cgroup *memcg,
> >                            int nid, int shrinker_id);
> > +extern void reparent_shrinker_deferred(struct mem_cgroup *memcg);
> >  #else
> >  #define mem_cgroup_sockets_enabled 0
> >  static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index f64ad0d044d9..21f36b73f36a 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -5282,6 +5282,7 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
> >       page_counter_set_low(&memcg->memory, 0);
> >
> >       memcg_offline_kmem(memcg);
> > +     reparent_shrinker_deferred(memcg);
> >       wb_memcg_offline(memcg);
> >
> >       drain_all_stock(memcg);
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 0373d7619d7b..55ad91a26ba3 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -386,6 +386,37 @@ static long set_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
> >       return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]);
> >  }
> >
> > +static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
> > +                                                  int nid)
> > +{
> > +     return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
> > +                                      lockdep_is_held(&shrinker_rwsem));
> > +}
> > +
> > +void reparent_shrinker_deferred(struct mem_cgroup *memcg)
> > +{
> > +     int i, nid;
> > +     long nr;
> > +     struct mem_cgroup *parent;
> > +     struct shrinker_info *child_info, *parent_info;
> > +
> > +     parent = parent_mem_cgroup(memcg);
> > +     if (!parent)
> > +             parent = root_mem_cgroup;
> > +
> > +     /* Prevent from concurrent shrinker_info expand */
> > +     down_read(&shrinker_rwsem);
> > +     for_each_node(nid) {
> > +             child_info = shrinker_info_protected(memcg, nid);
> > +             parent_info = shrinker_info_protected(parent, nid);
> > +             for (i = 0; i < shrinker_nr_max; i++) {
> > +                     nr = atomic_long_read(&child_info->nr_deferred[i]);
> > +                     atomic_long_add(nr, &parent_info->nr_deferred[i]);
> > +             }
> > +     }
> > +     up_read(&shrinker_rwsem);
> > +}
> > +
> >  static bool cgroup_reclaim(struct scan_control *sc)
> >  {
> >       return sc->target_mem_cgroup;
> >
>
diff mbox series

Patch

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e0384367e07d..fe1375f08881 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1586,6 +1586,7 @@  extern int alloc_shrinker_info(struct mem_cgroup *memcg);
 extern void free_shrinker_info(struct mem_cgroup *memcg);
 extern void set_shrinker_bit(struct mem_cgroup *memcg,
 			     int nid, int shrinker_id);
+extern void reparent_shrinker_deferred(struct mem_cgroup *memcg);
 #else
 #define mem_cgroup_sockets_enabled 0
 static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f64ad0d044d9..21f36b73f36a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5282,6 +5282,7 @@  static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
 	page_counter_set_low(&memcg->memory, 0);
 
 	memcg_offline_kmem(memcg);
+	reparent_shrinker_deferred(memcg);
 	wb_memcg_offline(memcg);
 
 	drain_all_stock(memcg);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 0373d7619d7b..55ad91a26ba3 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -386,6 +386,37 @@  static long set_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
 	return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]);
 }
 
+static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
+						     int nid)
+{
+	return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
+					 lockdep_is_held(&shrinker_rwsem));
+}
+
+void reparent_shrinker_deferred(struct mem_cgroup *memcg)
+{
+	int i, nid;
+	long nr;
+	struct mem_cgroup *parent;
+	struct shrinker_info *child_info, *parent_info;
+
+	parent = parent_mem_cgroup(memcg);
+	if (!parent)
+		parent = root_mem_cgroup;
+
+	/* Prevent from concurrent shrinker_info expand */
+	down_read(&shrinker_rwsem);
+	for_each_node(nid) {
+		child_info = shrinker_info_protected(memcg, nid);
+		parent_info = shrinker_info_protected(parent, nid);
+		for (i = 0; i < shrinker_nr_max; i++) {
+			nr = atomic_long_read(&child_info->nr_deferred[i]);
+			atomic_long_add(nr, &parent_info->nr_deferred[i]);
+		}
+	}
+	up_read(&shrinker_rwsem);
+}
+
 static bool cgroup_reclaim(struct scan_control *sc)
 {
 	return sc->target_mem_cgroup;