revert "memcg: track children in soft limit excess to improve soft limit"
Revert commit 7d910c054be4 ("memcg: track children in soft limit excess
to improve soft limit")
I merged this prematurely - Michal and Johannes still disagree about the
overall design direction and the future remains unclear.
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5cf7726..916892c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -124,7 +124,6 @@
*/
enum mem_cgroup_events_target {
MEM_CGROUP_TARGET_THRESH,
- MEM_CGROUP_TARGET_SOFTLIMIT,
MEM_CGROUP_TARGET_NUMAINFO,
MEM_CGROUP_NTARGETS,
};
@@ -303,22 +302,6 @@
atomic_t numainfo_events;
atomic_t numainfo_updating;
#endif
- /*
- * Protects soft_contributed transitions.
- * See mem_cgroup_update_soft_limit
- */
- spinlock_t soft_lock;
-
- /*
- * If true then this group has increased parents' children_in_excess
- * when it got over the soft limit.
- * When a group falls bellow the soft limit, parents' children_in_excess
- * is decreased and soft_contributed changed to false.
- */
- bool soft_contributed;
-
- /* Number of children that are in soft limit excess */
- atomic_t children_in_excess;
struct mem_cgroup_per_node *nodeinfo[0];
/* WARNING: nodeinfo must be the last member here */
@@ -806,9 +789,6 @@
case MEM_CGROUP_TARGET_THRESH:
next = val + THRESHOLDS_EVENTS_TARGET;
break;
- case MEM_CGROUP_TARGET_SOFTLIMIT:
- next = val + SOFTLIMIT_EVENTS_TARGET;
- break;
case MEM_CGROUP_TARGET_NUMAINFO:
next = val + NUMAINFO_EVENTS_TARGET;
break;
@@ -822,42 +802,6 @@
}
/*
- * Called from rate-limited memcg_check_events when enough
- * MEM_CGROUP_TARGET_SOFTLIMIT events are accumulated and it makes sure
- * that all the parents up the hierarchy will be notified that this group
- * is in excess or that it is not in excess anymore. mmecg->soft_contributed
- * makes the transition a single action whenever the state flips from one to
- * the other.
- */
-static void mem_cgroup_update_soft_limit(struct mem_cgroup *memcg)
-{
- unsigned long long excess = res_counter_soft_limit_excess(&memcg->res);
- struct mem_cgroup *parent = memcg;
- int delta = 0;
-
- spin_lock(&memcg->soft_lock);
- if (excess) {
- if (!memcg->soft_contributed) {
- delta = 1;
- memcg->soft_contributed = true;
- }
- } else {
- if (memcg->soft_contributed) {
- delta = -1;
- memcg->soft_contributed = false;
- }
- }
-
- /*
- * Necessary to update all ancestors when hierarchy is used
- * because their event counter is not touched.
- */
- while (delta && (parent = parent_mem_cgroup(parent)))
- atomic_add(delta, &parent->children_in_excess);
- spin_unlock(&memcg->soft_lock);
-}
-
-/*
* Check events in order.
*
*/
@@ -867,11 +811,8 @@
/* threshold event is triggered in finer grain than soft limit */
if (unlikely(mem_cgroup_event_ratelimit(memcg,
MEM_CGROUP_TARGET_THRESH))) {
- bool do_softlimit;
bool do_numainfo __maybe_unused;
- do_softlimit = mem_cgroup_event_ratelimit(memcg,
- MEM_CGROUP_TARGET_SOFTLIMIT);
#if MAX_NUMNODES > 1
do_numainfo = mem_cgroup_event_ratelimit(memcg,
MEM_CGROUP_TARGET_NUMAINFO);
@@ -879,8 +820,6 @@
preempt_enable();
mem_cgroup_threshold(memcg);
- if (unlikely(do_softlimit))
- mem_cgroup_update_soft_limit(memcg);
#if MAX_NUMNODES > 1
if (unlikely(do_numainfo))
atomic_inc(&memcg->numainfo_events);
@@ -1864,9 +1803,6 @@
* hierarchy if
* a) it is over its soft limit
* b) any parent up the hierarchy is over its soft limit
- *
- * If the given group doesn't have any children over the limit then it
- * doesn't make any sense to iterate its subtree.
*/
enum mem_cgroup_filter_t
mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
@@ -1888,8 +1824,6 @@
break;
}
- if (!atomic_read(&memcg->children_in_excess))
- return SKIP_TREE;
return SKIP;
}
@@ -6021,7 +5955,6 @@
mutex_init(&memcg->thresholds_lock);
spin_lock_init(&memcg->move_lock);
vmpressure_init(&memcg->vmpressure);
- spin_lock_init(&memcg->soft_lock);
return &memcg->css;
@@ -6099,10 +6032,6 @@
mem_cgroup_invalidate_reclaim_iterators(memcg);
mem_cgroup_reparent_charges(memcg);
- if (memcg->soft_contributed) {
- while ((memcg = parent_mem_cgroup(memcg)))
- atomic_dec(&memcg->children_in_excess);
- }
mem_cgroup_destroy_all_caches(memcg);
vmpressure_cleanup(&memcg->vmpressure);
}
