revert "memcg: enhance memcg iterator to support predicates"
Revert commit de57780dc659 ("memcg: enhance memcg iterator to support
predicates")
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 916892c..65e7bec 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -862,15 +862,6 @@
return memcg;
}
-static enum mem_cgroup_filter_t
-mem_cgroup_filter(struct mem_cgroup *memcg, struct mem_cgroup *root,
- mem_cgroup_iter_filter cond)
-{
- if (!cond)
- return VISIT;
- return cond(memcg, root);
-}
-
/*
* Returns a next (in a pre-order walk) alive memcg (with elevated css
* ref. count) or NULL if the whole root's subtree has been visited.
@@ -878,7 +869,7 @@
* helper function to be used by mem_cgroup_iter
*/
static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root,
- struct mem_cgroup *last_visited, mem_cgroup_iter_filter cond)
+ struct mem_cgroup *last_visited)
{
struct cgroup_subsys_state *prev_css, *next_css;
@@ -896,31 +887,11 @@
if (next_css) {
struct mem_cgroup *mem = mem_cgroup_from_css(next_css);
- switch (mem_cgroup_filter(mem, root, cond)) {
- case SKIP:
+ if (css_tryget(&mem->css))
+ return mem;
+ else {
prev_css = next_css;
goto skip_node;
- case SKIP_TREE:
- if (mem == root)
- return NULL;
- /*
- * css_rightmost_descendant is not an optimal way to
- * skip through a subtree (especially for imbalanced
- * trees leaning to right) but that's what we have right
- * now. More effective solution would be traversing
- * right-up for first non-NULL without calling
- * css_next_descendant_pre afterwards.
- */
- prev_css = css_rightmost_descendant(next_css);
- goto skip_node;
- case VISIT:
- if (css_tryget(&mem->css))
- return mem;
- else {
- prev_css = next_css;
- goto skip_node;
- }
- break;
}
}
@@ -984,7 +955,6 @@
* @root: hierarchy root
* @prev: previously returned memcg, NULL on first invocation
* @reclaim: cookie for shared reclaim walks, NULL for full walks
- * @cond: filter for visited nodes, NULL for no filter
*
* Returns references to children of the hierarchy below @root, or
* @root itself, or %NULL after a full round-trip.
@@ -997,18 +967,15 @@
* divide up the memcgs in the hierarchy among all concurrent
* reclaimers operating on the same zone and priority.
*/
-struct mem_cgroup *mem_cgroup_iter_cond(struct mem_cgroup *root,
+struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
struct mem_cgroup *prev,
- struct mem_cgroup_reclaim_cookie *reclaim,
- mem_cgroup_iter_filter cond)
+ struct mem_cgroup_reclaim_cookie *reclaim)
{
struct mem_cgroup *memcg = NULL;
struct mem_cgroup *last_visited = NULL;
- if (mem_cgroup_disabled()) {
- /* first call must return non-NULL, second return NULL */
- return (struct mem_cgroup *)(unsigned long)!prev;
- }
+ if (mem_cgroup_disabled())
+ return NULL;
if (!root)
root = root_mem_cgroup;
@@ -1019,9 +986,7 @@
if (!root->use_hierarchy && root != root_mem_cgroup) {
if (prev)
goto out_css_put;
- if (mem_cgroup_filter(root, root, cond) == VISIT)
- return root;
- return NULL;
+ return root;
}
rcu_read_lock();
@@ -1044,7 +1009,7 @@
last_visited = mem_cgroup_iter_load(iter, root, &seq);
}
- memcg = __mem_cgroup_iter_next(root, last_visited, cond);
+ memcg = __mem_cgroup_iter_next(root, last_visited);
if (reclaim) {
mem_cgroup_iter_update(iter, last_visited, memcg, seq);
@@ -1055,11 +1020,7 @@
reclaim->generation = iter->generation;
}
- /*
- * We have finished the whole tree walk or no group has been
- * visited because filter told us to skip the root node.
- */
- if (!memcg && (prev || (cond && !last_visited)))
+ if (prev && !memcg)
goto out_unlock;
}
out_unlock:
@@ -1804,14 +1765,13 @@
* a) it is over its soft limit
* b) any parent up the hierarchy is over its soft limit
*/
-enum mem_cgroup_filter_t
-mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
+bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
struct mem_cgroup *root)
{
struct mem_cgroup *parent = memcg;
if (res_counter_soft_limit_excess(&memcg->res))
- return VISIT;
+ return true;
/*
* If any parent up to the root in the hierarchy is over its soft limit
@@ -1819,12 +1779,12 @@
*/
while ((parent = parent_mem_cgroup(parent))) {
if (res_counter_soft_limit_excess(&parent->res))
- return VISIT;
+ return true;
if (parent == root)
break;
}
- return SKIP;
+ return false;
}
static DEFINE_SPINLOCK(memcg_oom_lock);