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