2020-12-14 22:49:00

by Yang Shi

[permalink] [raw]
Subject: [v2 PATCH 8/9] mm: memcontrol: reparent nr_deferred when memcg offline

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 <[email protected]>
---
include/linux/shrinker.h | 4 ++++
mm/memcontrol.c | 24 ++++++++++++++++++++++++
mm/vmscan.c | 2 +-
3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
index 1eac79ce57d4..85cfc910dde4 100644
--- a/include/linux/shrinker.h
+++ b/include/linux/shrinker.h
@@ -78,6 +78,10 @@ struct shrinker {
};
#define DEFAULT_SEEKS 2 /* A good number if you don't know better. */

+#ifdef CONFIG_MEMCG
+extern int shrinker_nr_max;
+#endif
+
/* Flags */
#define SHRINKER_REGISTERED (1 << 0)
#define SHRINKER_NUMA_AWARE (1 << 1)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 321d1818ce3d..1f191a15bee1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -59,6 +59,7 @@
#include <linux/tracehook.h>
#include <linux/psi.h>
#include <linux/seq_buf.h>
+#include <linux/shrinker.h>
#include "internal.h"
#include <net/sock.h>
#include <net/ip.h>
@@ -612,6 +613,28 @@ void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
}
}

+static void memcg_reparent_shrinker_deferred(struct mem_cgroup *memcg)
+{
+ int i, nid;
+ long nr;
+ struct mem_cgroup *parent;
+ struct memcg_shrinker_deferred *child_deferred, *parent_deferred;
+
+ parent = parent_mem_cgroup(memcg);
+ if (!parent)
+ parent = root_mem_cgroup;
+
+ for_each_node(nid) {
+ child_deferred = memcg->nodeinfo[nid]->shrinker_deferred;
+ parent_deferred = parent->nodeinfo[nid]->shrinker_deferred;
+ for (i = 0; i < shrinker_nr_max; i ++) {
+ nr = atomic_long_read(&child_deferred->nr_deferred[i]);
+ atomic_long_add(nr,
+ &parent_deferred->nr_deferred[i]);
+ }
+ }
+}
+
/**
* mem_cgroup_css_from_page - css of the memcg associated with a page
* @page: page of interest
@@ -5543,6 +5566,7 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
page_counter_set_low(&memcg->memory, 0);

memcg_offline_kmem(memcg);
+ memcg_reparent_shrinker_deferred(memcg);
wb_memcg_offline(memcg);

drain_all_stock(memcg);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8d5bfd818acd..693a41e89969 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -201,7 +201,7 @@ DECLARE_RWSEM(shrinker_rwsem);
#define SHRINKER_REGISTERING ((struct shrinker *)~0UL)

static DEFINE_IDR(shrinker_idr);
-static int shrinker_nr_max;
+int shrinker_nr_max;

static inline bool is_deferred_memcg_aware(struct shrinker *shrinker)
{
--
2.26.2


2020-12-15 03:12:15

by Dave Chinner

[permalink] [raw]
Subject: Re: [v2 PATCH 8/9] mm: memcontrol: reparent nr_deferred when memcg offline

On Mon, Dec 14, 2020 at 02:37:21PM -0800, 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 <[email protected]>
> ---
> include/linux/shrinker.h | 4 ++++
> mm/memcontrol.c | 24 ++++++++++++++++++++++++
> mm/vmscan.c | 2 +-
> 3 files changed, 29 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
> index 1eac79ce57d4..85cfc910dde4 100644
> --- a/include/linux/shrinker.h
> +++ b/include/linux/shrinker.h
> @@ -78,6 +78,10 @@ struct shrinker {
> };
> #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
>
> +#ifdef CONFIG_MEMCG
> +extern int shrinker_nr_max;
> +#endif
> +
> /* Flags */
> #define SHRINKER_REGISTERED (1 << 0)
> #define SHRINKER_NUMA_AWARE (1 << 1)
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 321d1818ce3d..1f191a15bee1 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -59,6 +59,7 @@
> #include <linux/tracehook.h>
> #include <linux/psi.h>
> #include <linux/seq_buf.h>
> +#include <linux/shrinker.h>
> #include "internal.h"
> #include <net/sock.h>
> #include <net/ip.h>
> @@ -612,6 +613,28 @@ void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
> }
> }
>
> +static void memcg_reparent_shrinker_deferred(struct mem_cgroup *memcg)
> +{
> + int i, nid;
> + long nr;
> + struct mem_cgroup *parent;
> + struct memcg_shrinker_deferred *child_deferred, *parent_deferred;
> +
> + parent = parent_mem_cgroup(memcg);
> + if (!parent)
> + parent = root_mem_cgroup;
> +
> + for_each_node(nid) {
> + child_deferred = memcg->nodeinfo[nid]->shrinker_deferred;
> + parent_deferred = parent->nodeinfo[nid]->shrinker_deferred;
> + for (i = 0; i < shrinker_nr_max; i ++) {
> + nr = atomic_long_read(&child_deferred->nr_deferred[i]);
> + atomic_long_add(nr,
> + &parent_deferred->nr_deferred[i]);
> + }
> + }
> +}

I would place this function in vmscan.c alongside the
shrink_slab_set_nr_deferred_memcg() function so that all the
accounting is in the one place.

> +
> /**
> * mem_cgroup_css_from_page - css of the memcg associated with a page
> * @page: page of interest
> @@ -5543,6 +5566,7 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
> page_counter_set_low(&memcg->memory, 0);
>
> memcg_offline_kmem(memcg);
> + memcg_reparent_shrinker_deferred(memcg);
> wb_memcg_offline(memcg);
>
> drain_all_stock(memcg);
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 8d5bfd818acd..693a41e89969 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -201,7 +201,7 @@ DECLARE_RWSEM(shrinker_rwsem);
> #define SHRINKER_REGISTERING ((struct shrinker *)~0UL)
>
> static DEFINE_IDR(shrinker_idr);
> -static int shrinker_nr_max;
> +int shrinker_nr_max;

Then we don't need to make yet another variable global...

Cheers,

Dave.
--
Dave Chinner
[email protected]

2020-12-15 23:13:56

by Yang Shi

[permalink] [raw]
Subject: Re: [v2 PATCH 8/9] mm: memcontrol: reparent nr_deferred when memcg offline

On Mon, Dec 14, 2020 at 7:08 PM Dave Chinner <[email protected]> wrote:
>
> On Mon, Dec 14, 2020 at 02:37:21PM -0800, 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 <[email protected]>
> > ---
> > include/linux/shrinker.h | 4 ++++
> > mm/memcontrol.c | 24 ++++++++++++++++++++++++
> > mm/vmscan.c | 2 +-
> > 3 files changed, 29 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
> > index 1eac79ce57d4..85cfc910dde4 100644
> > --- a/include/linux/shrinker.h
> > +++ b/include/linux/shrinker.h
> > @@ -78,6 +78,10 @@ struct shrinker {
> > };
> > #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
> >
> > +#ifdef CONFIG_MEMCG
> > +extern int shrinker_nr_max;
> > +#endif
> > +
> > /* Flags */
> > #define SHRINKER_REGISTERED (1 << 0)
> > #define SHRINKER_NUMA_AWARE (1 << 1)
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index 321d1818ce3d..1f191a15bee1 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -59,6 +59,7 @@
> > #include <linux/tracehook.h>
> > #include <linux/psi.h>
> > #include <linux/seq_buf.h>
> > +#include <linux/shrinker.h>
> > #include "internal.h"
> > #include <net/sock.h>
> > #include <net/ip.h>
> > @@ -612,6 +613,28 @@ void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
> > }
> > }
> >
> > +static void memcg_reparent_shrinker_deferred(struct mem_cgroup *memcg)
> > +{
> > + int i, nid;
> > + long nr;
> > + struct mem_cgroup *parent;
> > + struct memcg_shrinker_deferred *child_deferred, *parent_deferred;
> > +
> > + parent = parent_mem_cgroup(memcg);
> > + if (!parent)
> > + parent = root_mem_cgroup;
> > +
> > + for_each_node(nid) {
> > + child_deferred = memcg->nodeinfo[nid]->shrinker_deferred;
> > + parent_deferred = parent->nodeinfo[nid]->shrinker_deferred;
> > + for (i = 0; i < shrinker_nr_max; i ++) {
> > + nr = atomic_long_read(&child_deferred->nr_deferred[i]);
> > + atomic_long_add(nr,
> > + &parent_deferred->nr_deferred[i]);
> > + }
> > + }
> > +}
>
> I would place this function in vmscan.c alongside the
> shrink_slab_set_nr_deferred_memcg() function so that all the
> accounting is in the one place.

Fine to me. Will incorporate in v3.

>
> > +
> > /**
> > * mem_cgroup_css_from_page - css of the memcg associated with a page
> > * @page: page of interest
> > @@ -5543,6 +5566,7 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
> > page_counter_set_low(&memcg->memory, 0);
> >
> > memcg_offline_kmem(memcg);
> > + memcg_reparent_shrinker_deferred(memcg);
> > wb_memcg_offline(memcg);
> >
> > drain_all_stock(memcg);
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 8d5bfd818acd..693a41e89969 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -201,7 +201,7 @@ DECLARE_RWSEM(shrinker_rwsem);
> > #define SHRINKER_REGISTERING ((struct shrinker *)~0UL)
> >
> > static DEFINE_IDR(shrinker_idr);
> > -static int shrinker_nr_max;
> > +int shrinker_nr_max;
>
> Then we don't need to make yet another variable global...
>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> [email protected]