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-rw-r--r--include/linux/memcontrol.h7
-rw-r--r--kernel/cgroup/cgroup.c5
-rw-r--r--mm/memcontrol.c90
3 files changed, 13 insertions, 89 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 1f0f64fa3ccd..dd992b81bcb7 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -235,11 +235,6 @@ struct mem_cgroup {
struct vmpressure vmpressure;
/*
- * Should the accounting and control be hierarchical, per subtree?
- */
- bool use_hierarchy;
-
- /*
* Should the OOM killer kill all belonging tasks, had it kill one?
*/
bool oom_group;
@@ -588,8 +583,6 @@ static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg,
{
if (root == memcg)
return true;
- if (!root->use_hierarchy)
- return false;
return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
}
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index e41c21819ba0..80c5c34416e8 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -281,9 +281,6 @@ bool cgroup_ssid_enabled(int ssid)
* - cpuset: a task can be moved into an empty cpuset, and again it takes
* masks of ancestors.
*
- * - memcg: use_hierarchy is on by default and the cgroup file for the flag
- * is not created.
- *
* - blkcg: blk-throttle becomes properly hierarchical.
*
* - debug: disallowed on the default hierarchy.
@@ -5156,8 +5153,6 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
cgroup_parent(parent)) {
pr_warn("%s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n",
current->comm, current->pid, ss->name);
- if (!strcmp(ss->name, "memory"))
- pr_warn("\"memory\" requires setting use_hierarchy to 1 on the root\n");
ss->warned_broken_hierarchy = true;
}
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 466d9aed6cc8..fc18a2b7d25a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1141,12 +1141,6 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
if (prev && !reclaim)
pos = prev;
- if (!root->use_hierarchy && root != root_mem_cgroup) {
- if (prev)
- goto out;
- return root;
- }
-
rcu_read_lock();
if (reclaim) {
@@ -1226,7 +1220,6 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
out_unlock:
rcu_read_unlock();
-out:
if (prev && prev != root)
css_put(&prev->css);
@@ -3461,10 +3454,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
}
/*
- * Test whether @memcg has children, dead or alive. Note that this
- * function doesn't care whether @memcg has use_hierarchy enabled and
- * returns %true if there are child csses according to the cgroup
- * hierarchy. Testing use_hierarchy is the caller's responsibility.
+ * Test whether @memcg has children, dead or alive.
*/
static inline bool memcg_has_children(struct mem_cgroup *memcg)
{
@@ -3524,37 +3514,20 @@ static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
- return mem_cgroup_from_css(css)->use_hierarchy;
+ return 1;
}
static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
struct cftype *cft, u64 val)
{
- int retval = 0;
- struct mem_cgroup *memcg = mem_cgroup_from_css(css);
- struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
-
- if (memcg->use_hierarchy == val)
+ if (val == 1)
return 0;
- /*
- * If parent's use_hierarchy is set, we can't make any modifications
- * in the child subtrees. If it is unset, then the change can
- * occur, provided the current cgroup has no children.
- *
- * For the root cgroup, parent_mem is NULL, we allow value to be
- * set if there are no children.
- */
- if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
- (val == 1 || val == 0)) {
- if (!memcg_has_children(memcg))
- memcg->use_hierarchy = val;
- else
- retval = -EBUSY;
- } else
- retval = -EINVAL;
+ pr_warn_once("Non-hierarchical mode is deprecated. "
+ "Please report your usecase to linux-mm@kvack.org if you "
+ "depend on this functionality.\n");
- return retval;
+ return -EINVAL;
}
static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
@@ -3742,8 +3715,6 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
child = mem_cgroup_from_css(css);
BUG_ON(child->kmemcg_id != kmemcg_id);
child->kmemcg_id = parent->kmemcg_id;
- if (!memcg->use_hierarchy)
- break;
}
rcu_read_unlock();
@@ -5334,38 +5305,22 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
if (parent) {
memcg->swappiness = mem_cgroup_swappiness(parent);
memcg->oom_kill_disable = parent->oom_kill_disable;
- }
- if (!parent) {
- page_counter_init(&memcg->memory, NULL);
- page_counter_init(&memcg->swap, NULL);
- page_counter_init(&memcg->kmem, NULL);
- page_counter_init(&memcg->tcpmem, NULL);
- } else if (parent->use_hierarchy) {
- memcg->use_hierarchy = true;
+
page_counter_init(&memcg->memory, &parent->memory);
page_counter_init(&memcg->swap, &parent->swap);
page_counter_init(&memcg->kmem, &parent->kmem);
page_counter_init(&memcg->tcpmem, &parent->tcpmem);
} else {
- page_counter_init(&memcg->memory, &root_mem_cgroup->memory);
- page_counter_init(&memcg->swap, &root_mem_cgroup->swap);
- page_counter_init(&memcg->kmem, &root_mem_cgroup->kmem);
- page_counter_init(&memcg->tcpmem, &root_mem_cgroup->tcpmem);
- /*
- * Deeper hierachy with use_hierarchy == false doesn't make
- * much sense so let cgroup subsystem know about this
- * unfortunate state in our controller.
- */
- if (parent != root_mem_cgroup)
- memory_cgrp_subsys.broken_hierarchy = true;
- }
+ page_counter_init(&memcg->memory, NULL);
+ page_counter_init(&memcg->swap, NULL);
+ page_counter_init(&memcg->kmem, NULL);
+ page_counter_init(&memcg->tcpmem, NULL);
- /* The following stuff does not apply to the root */
- if (!parent) {
root_mem_cgroup = memcg;
return &memcg->css;
}
+ /* The following stuff does not apply to the root */
error = memcg_online_kmem(memcg);
if (error)
goto fail;
@@ -6202,24 +6157,6 @@ static void mem_cgroup_move_task(void)
}
#endif
-/*
- * Cgroup retains root cgroups across [un]mount cycles making it necessary
- * to verify whether we're attached to the default hierarchy on each mount
- * attempt.
- */
-static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
-{
- /*
- * use_hierarchy is forced on the default hierarchy. cgroup core
- * guarantees that @root doesn't have any children, so turning it
- * on for the root memcg is enough.
- */
- if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
- root_mem_cgroup->use_hierarchy = true;
- else
- root_mem_cgroup->use_hierarchy = false;
-}
-
static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value)
{
if (value == PAGE_COUNTER_MAX)
@@ -6557,7 +6494,6 @@ struct cgroup_subsys memory_cgrp_subsys = {
.can_attach = mem_cgroup_can_attach,
.cancel_attach = mem_cgroup_cancel_attach,
.post_attach = mem_cgroup_move_task,
- .bind = mem_cgroup_bind,
.dfl_cftypes = memory_files,
.legacy_cftypes = mem_cgroup_legacy_files,
.early_init = 0,