diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 70 |
1 files changed, 55 insertions, 15 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c016e001c5b..a4bb857d902 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -875,6 +875,15 @@ struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) 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. @@ -882,7 +891,7 @@ struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) * 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) + struct mem_cgroup *last_visited, mem_cgroup_iter_filter cond) { struct cgroup_subsys_state *prev_css, *next_css; @@ -900,11 +909,31 @@ skip_node: if (next_css) { struct mem_cgroup *mem = mem_cgroup_from_css(next_css); - if (css_tryget(&mem->css)) - return mem; - else { + switch (mem_cgroup_filter(mem, root, cond)) { + case SKIP: 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; } } @@ -968,6 +997,7 @@ static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, * @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. @@ -980,15 +1010,18 @@ static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter, * divide up the memcgs in the hierarchy among all concurrent * reclaimers operating on the same zone and priority. */ -struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, +struct mem_cgroup *mem_cgroup_iter_cond(struct mem_cgroup *root, struct mem_cgroup *prev, - struct mem_cgroup_reclaim_cookie *reclaim) + struct mem_cgroup_reclaim_cookie *reclaim, + mem_cgroup_iter_filter cond) { struct mem_cgroup *memcg = NULL; struct mem_cgroup *last_visited = NULL; - if (mem_cgroup_disabled()) - return NULL; + if (mem_cgroup_disabled()) { + /* first call must return non-NULL, second return NULL */ + return (struct mem_cgroup *)(unsigned long)!prev; + } if (!root) root = root_mem_cgroup; @@ -999,7 +1032,9 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, if (!root->use_hierarchy && root != root_mem_cgroup) { if (prev) goto out_css_put; - return root; + if (mem_cgroup_filter(root, root, cond) == VISIT) + return root; + return NULL; } rcu_read_lock(); @@ -1022,7 +1057,7 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, last_visited = mem_cgroup_iter_load(iter, root, &seq); } - memcg = __mem_cgroup_iter_next(root, last_visited); + memcg = __mem_cgroup_iter_next(root, last_visited, cond); if (reclaim) { mem_cgroup_iter_update(iter, last_visited, memcg, seq); @@ -1033,7 +1068,11 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, reclaim->generation = iter->generation; } - if (prev && !memcg) + /* + * 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))) goto out_unlock; } out_unlock: @@ -1778,13 +1817,14 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) * a) it is over its soft limit * b) any parent up the hierarchy is over its soft limit */ -bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg, +enum mem_cgroup_filter_t +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 true; + return VISIT; /* * If any parent up to the root in the hierarchy is over its soft limit @@ -1792,12 +1832,12 @@ bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg, */ while((parent = parent_mem_cgroup(parent))) { if (res_counter_soft_limit_excess(&parent->res)) - return true; + return VISIT; if (parent == root) break; } - return false; + return SKIP; } /* |