diff options
| -rw-r--r-- | mm/memcontrol.c | 166 |
1 files changed, 162 insertions, 4 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e72fb2b4a7d..20e1d90b336 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -143,6 +143,13 @@ struct mem_cgroup { struct mem_cgroup_lru_info info; int prev_priority; /* for recording reclaim priority */ + + /* + * While reclaiming in a hiearchy, we cache the last child we + * reclaimed from. Protected by cgroup_lock() + */ + struct mem_cgroup *last_scanned_child; + int obsolete; atomic_t refcnt; /* @@ -461,6 +468,149 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, return nr_taken; } +#define mem_cgroup_from_res_counter(counter, member) \ + container_of(counter, struct mem_cgroup, member) + +/* + * This routine finds the DFS walk successor. This routine should be + * called with cgroup_mutex held + */ +static struct mem_cgroup * +mem_cgroup_get_next_node(struct mem_cgroup *curr, struct mem_cgroup *root_mem) +{ + struct cgroup *cgroup, *curr_cgroup, *root_cgroup; + + curr_cgroup = curr->css.cgroup; + root_cgroup = root_mem->css.cgroup; + + if (!list_empty(&curr_cgroup->children)) { + /* + * Walk down to children + */ + mem_cgroup_put(curr); + cgroup = list_entry(curr_cgroup->children.next, + struct cgroup, sibling); + curr = mem_cgroup_from_cont(cgroup); + mem_cgroup_get(curr); + goto done; + } + +visit_parent: + if (curr_cgroup == root_cgroup) { + mem_cgroup_put(curr); + curr = root_mem; + mem_cgroup_get(curr); + goto done; + } + + /* + * Goto next sibling + */ + if (curr_cgroup->sibling.next != &curr_cgroup->parent->children) { + mem_cgroup_put(curr); + cgroup = list_entry(curr_cgroup->sibling.next, struct cgroup, + sibling); + curr = mem_cgroup_from_cont(cgroup); + mem_cgroup_get(curr); + goto done; + } + + /* + * Go up to next parent and next parent's sibling if need be + */ + curr_cgroup = curr_cgroup->parent; + goto visit_parent; + +done: + root_mem->last_scanned_child = curr; + return curr; +} + +/* + * Visit the first child (need not be the first child as per the ordering + * of the cgroup list, since we track last_scanned_child) of @mem and use + * that to reclaim free pages from. + */ +static struct mem_cgroup * +mem_cgroup_get_first_node(struct mem_cgroup *root_mem) +{ + struct cgroup *cgroup; + struct mem_cgroup *ret; + bool obsolete = (root_mem->last_scanned_child && + root_mem->last_scanned_child->obsolete); + + /* + * Scan all children under the mem_cgroup mem + */ + cgroup_lock(); + if (list_empty(&root_mem->css.cgroup->children)) { + ret = root_mem; + goto done; + } + + if (!root_mem->last_scanned_child || obsolete) { + + if (obsolete) + mem_cgroup_put(root_mem->last_scanned_child); + + cgroup = list_first_entry(&root_mem->css.cgroup->children, + struct cgroup, sibling); + ret = mem_cgroup_from_cont(cgroup); + mem_cgroup_get(ret); + } else + ret = mem_cgroup_get_next_node(root_mem->last_scanned_child, + root_mem); + +done: + root_mem->last_scanned_child = ret; + cgroup_unlock(); + return ret; +} + +/* + * Dance down the hierarchy if needed to reclaim memory. We remember the + * last child we reclaimed from, so that we don't end up penalizing + * one child extensively based on its position in the children list. + * + * root_mem is the original ancestor that we've been reclaim from. + */ +static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, + gfp_t gfp_mask, bool noswap) +{ + struct mem_cgroup *next_mem; + int ret = 0; + + /* + * Reclaim unconditionally and don't check for return value. + * We need to reclaim in the current group and down the tree. + * One might think about checking for children before reclaiming, + * but there might be left over accounting, even after children + * have left. + */ + ret = try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap); + if (res_counter_check_under_limit(&root_mem->res)) + return 0; + + next_mem = mem_cgroup_get_first_node(root_mem); + + while (next_mem != root_mem) { + if (next_mem->obsolete) { + mem_cgroup_put(next_mem); + cgroup_lock(); + next_mem = mem_cgroup_get_first_node(root_mem); + cgroup_unlock(); + continue; + } + ret = try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap); + if (res_counter_check_under_limit(&root_mem->res)) + return 0; + cgroup_lock(); + next_mem = mem_cgroup_get_next_node(next_mem, root_mem); + cgroup_unlock(); + } + return ret; +} + /* * Unlike exported interface, "oom" parameter is added. if oom==true, * oom-killer can be invoked. @@ -469,7 +619,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom) { - struct mem_cgroup *mem; + struct mem_cgroup *mem, *mem_over_limit; int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; struct res_counter *fail_res; /* @@ -511,12 +661,18 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, /* mem+swap counter fails */ res_counter_uncharge(&mem->res, PAGE_SIZE); noswap = true; - } + mem_over_limit = mem_cgroup_from_res_counter(fail_res, + memsw); + } else + /* mem counter fails */ + mem_over_limit = mem_cgroup_from_res_counter(fail_res, + res); + if (!(gfp_mask & __GFP_WAIT)) goto nomem; - if (try_to_free_mem_cgroup_pages(mem, gfp_mask, noswap)) - continue; + ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask, + noswap); /* * try_to_free_mem_cgroup_pages() might not give us a full @@ -1732,6 +1888,8 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) res_counter_init(&mem->memsw, parent ? &parent->memsw : NULL); + mem->last_scanned_child = NULL; + return &mem->css; free_out: for_each_node_state(node, N_POSSIBLE) |