diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 871 |
1 files changed, 337 insertions, 534 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c6bd28e..d5ff3ce 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -39,7 +39,6 @@ #include <linux/limits.h> #include <linux/export.h> #include <linux/mutex.h> -#include <linux/rbtree.h> #include <linux/slab.h> #include <linux/swap.h> #include <linux/swapops.h> @@ -85,26 +84,12 @@ static int really_do_swap_account __initdata = 0; #endif -/* - * Statistics for memory cgroup. - */ -enum mem_cgroup_stat_index { - /* - * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. - */ - MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ - MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */ - MEM_CGROUP_STAT_RSS_HUGE, /* # of pages charged as anon huge */ - MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ - MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */ - MEM_CGROUP_STAT_NSTATS, -}; - static const char * const mem_cgroup_stat_names[] = { "cache", "rss", "rss_huge", "mapped_file", + "writeback", "swap", }; @@ -175,10 +160,6 @@ struct mem_cgroup_per_zone { struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1]; - struct rb_node tree_node; /* RB tree node */ - unsigned long long usage_in_excess;/* Set to the value by which */ - /* the soft limit is exceeded*/ - bool on_tree; struct mem_cgroup *memcg; /* Back pointer, we cannot */ /* use container_of */ }; @@ -187,26 +168,6 @@ struct mem_cgroup_per_node { struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; }; -/* - * Cgroups above their limits are maintained in a RB-Tree, independent of - * their hierarchy representation - */ - -struct mem_cgroup_tree_per_zone { - struct rb_root rb_root; - spinlock_t lock; -}; - -struct mem_cgroup_tree_per_node { - struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; -}; - -struct mem_cgroup_tree { - struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; -}; - -static struct mem_cgroup_tree soft_limit_tree __read_mostly; - struct mem_cgroup_threshold { struct eventfd_ctx *eventfd; u64 threshold; @@ -280,6 +241,7 @@ struct mem_cgroup { bool oom_lock; atomic_t under_oom; + atomic_t oom_wakeups; int swappiness; /* OOM-Killer disable */ @@ -304,7 +266,7 @@ struct mem_cgroup { * Should we move charges of a task when a task is moved into this * mem_cgroup ? And what type of charges should we move ? */ - unsigned long move_charge_at_immigrate; + unsigned long move_charge_at_immigrate; /* * set > 0 if pages under this cgroup are moving to other cgroup. */ @@ -341,6 +303,22 @@ struct mem_cgroup { 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 */ @@ -444,7 +422,6 @@ static bool move_file(void) * limit reclaim to prevent infinite loops, if they ever occur. */ #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100 -#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2 enum charge_type { MEM_CGROUP_CHARGE_TYPE_CACHE = 0, @@ -671,164 +648,6 @@ page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page) return mem_cgroup_zoneinfo(memcg, nid, zid); } -static struct mem_cgroup_tree_per_zone * -soft_limit_tree_node_zone(int nid, int zid) -{ - return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; -} - -static struct mem_cgroup_tree_per_zone * -soft_limit_tree_from_page(struct page *page) -{ - int nid = page_to_nid(page); - int zid = page_zonenum(page); - - return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; -} - -static void -__mem_cgroup_insert_exceeded(struct mem_cgroup *memcg, - struct mem_cgroup_per_zone *mz, - struct mem_cgroup_tree_per_zone *mctz, - unsigned long long new_usage_in_excess) -{ - struct rb_node **p = &mctz->rb_root.rb_node; - struct rb_node *parent = NULL; - struct mem_cgroup_per_zone *mz_node; - - if (mz->on_tree) - return; - - mz->usage_in_excess = new_usage_in_excess; - if (!mz->usage_in_excess) - return; - while (*p) { - parent = *p; - mz_node = rb_entry(parent, struct mem_cgroup_per_zone, - tree_node); - if (mz->usage_in_excess < mz_node->usage_in_excess) - p = &(*p)->rb_left; - /* - * We can't avoid mem cgroups that are over their soft - * limit by the same amount - */ - else if (mz->usage_in_excess >= mz_node->usage_in_excess) - p = &(*p)->rb_right; - } - rb_link_node(&mz->tree_node, parent, p); - rb_insert_color(&mz->tree_node, &mctz->rb_root); - mz->on_tree = true; -} - -static void -__mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, - struct mem_cgroup_per_zone *mz, - struct mem_cgroup_tree_per_zone *mctz) -{ - if (!mz->on_tree) - return; - rb_erase(&mz->tree_node, &mctz->rb_root); - mz->on_tree = false; -} - -static void -mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, - struct mem_cgroup_per_zone *mz, - struct mem_cgroup_tree_per_zone *mctz) -{ - spin_lock(&mctz->lock); - __mem_cgroup_remove_exceeded(memcg, mz, mctz); - spin_unlock(&mctz->lock); -} - - -static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) -{ - unsigned long long excess; - struct mem_cgroup_per_zone *mz; - struct mem_cgroup_tree_per_zone *mctz; - int nid = page_to_nid(page); - int zid = page_zonenum(page); - mctz = soft_limit_tree_from_page(page); - - /* - * Necessary to update all ancestors when hierarchy is used. - * because their event counter is not touched. - */ - for (; memcg; memcg = parent_mem_cgroup(memcg)) { - mz = mem_cgroup_zoneinfo(memcg, nid, zid); - excess = res_counter_soft_limit_excess(&memcg->res); - /* - * We have to update the tree if mz is on RB-tree or - * mem is over its softlimit. - */ - if (excess || mz->on_tree) { - spin_lock(&mctz->lock); - /* if on-tree, remove it */ - if (mz->on_tree) - __mem_cgroup_remove_exceeded(memcg, mz, mctz); - /* - * Insert again. mz->usage_in_excess will be updated. - * If excess is 0, no tree ops. - */ - __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess); - spin_unlock(&mctz->lock); - } - } -} - -static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) -{ - int node, zone; - struct mem_cgroup_per_zone *mz; - struct mem_cgroup_tree_per_zone *mctz; - - for_each_node(node) { - for (zone = 0; zone < MAX_NR_ZONES; zone++) { - mz = mem_cgroup_zoneinfo(memcg, node, zone); - mctz = soft_limit_tree_node_zone(node, zone); - mem_cgroup_remove_exceeded(memcg, mz, mctz); - } - } -} - -static struct mem_cgroup_per_zone * -__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) -{ - struct rb_node *rightmost = NULL; - struct mem_cgroup_per_zone *mz; - -retry: - mz = NULL; - rightmost = rb_last(&mctz->rb_root); - if (!rightmost) - goto done; /* Nothing to reclaim from */ - - mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); - /* - * Remove the node now but someone else can add it back, - * we will to add it back at the end of reclaim to its correct - * position in the tree. - */ - __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); - if (!res_counter_soft_limit_excess(&mz->memcg->res) || - !css_tryget(&mz->memcg->css)) - goto retry; -done: - return mz; -} - -static struct mem_cgroup_per_zone * -mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) -{ - struct mem_cgroup_per_zone *mz; - - spin_lock(&mctz->lock); - mz = __mem_cgroup_largest_soft_limit_node(mctz); - spin_unlock(&mctz->lock); - return mz; -} - /* * Implementation Note: reading percpu statistics for memcg. * @@ -1003,6 +822,48 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, } /* + * 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. + * We track children even outside the hierarchy for the root + * cgroup because tree walk starting at root should visit + * all cgroups and we want to prevent from pointless tree + * walk if no children is below the limit. + */ + while (delta && (parent = parent_mem_cgroup(parent))) + atomic_add(delta, &parent->children_in_excess); + if (memcg != root_mem_cgroup && !root_mem_cgroup->use_hierarchy) + atomic_add(delta, &root_mem_cgroup->children_in_excess); + spin_unlock(&memcg->soft_lock); +} + +/* * Check events in order. * */ @@ -1025,7 +886,7 @@ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) mem_cgroup_threshold(memcg); if (unlikely(do_softlimit)) - mem_cgroup_update_tree(memcg, page); + mem_cgroup_update_soft_limit(memcg); #if MAX_NUMNODES > 1 if (unlikely(do_numainfo)) atomic_inc(&memcg->numainfo_events); @@ -1068,6 +929,15 @@ 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. @@ -1075,7 +945,7 @@ 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; @@ -1093,11 +963,31 @@ 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; } } @@ -1161,6 +1051,7 @@ 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. @@ -1173,15 +1064,18 @@ 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; @@ -1192,7 +1086,9 @@ 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(); @@ -1215,7 +1111,7 @@ 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); @@ -1226,7 +1122,11 @@ 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: @@ -1867,6 +1767,7 @@ static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg, return total; } +#if MAX_NUMNODES > 1 /** * test_mem_cgroup_node_reclaimable * @memcg: the target memcg @@ -1889,7 +1790,6 @@ static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg, return false; } -#if MAX_NUMNODES > 1 /* * Always updating the nodemask is not very good - even if we have an empty @@ -1957,115 +1857,64 @@ int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) return node; } -/* - * Check all nodes whether it contains reclaimable pages or not. - * For quick scan, we make use of scan_nodes. This will allow us to skip - * unused nodes. But scan_nodes is lazily updated and may not cotain - * enough new information. We need to do double check. - */ -static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) -{ - int nid; - - /* - * quick check...making use of scan_node. - * We can skip unused nodes. - */ - if (!nodes_empty(memcg->scan_nodes)) { - for (nid = first_node(memcg->scan_nodes); - nid < MAX_NUMNODES; - nid = next_node(nid, memcg->scan_nodes)) { - - if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) - return true; - } - } - /* - * Check rest of nodes. - */ - for_each_node_state(nid, N_MEMORY) { - if (node_isset(nid, memcg->scan_nodes)) - continue; - if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) - return true; - } - return false; -} - #else int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) { return 0; } -static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) -{ - return test_mem_cgroup_node_reclaimable(memcg, 0, noswap); -} #endif -static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg, - struct zone *zone, - gfp_t gfp_mask, - unsigned long *total_scanned) -{ - struct mem_cgroup *victim = NULL; - int total = 0; - int loop = 0; - unsigned long excess; - unsigned long nr_scanned; - struct mem_cgroup_reclaim_cookie reclaim = { - .zone = zone, - .priority = 0, - }; - - excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT; - - while (1) { - victim = mem_cgroup_iter(root_memcg, victim, &reclaim); - if (!victim) { - loop++; - if (loop >= 2) { - /* - * If we have not been able to reclaim - * anything, it might because there are - * no reclaimable pages under this hierarchy - */ - if (!total) - break; - /* - * We want to do more targeted reclaim. - * excess >> 2 is not to excessive so as to - * reclaim too much, nor too less that we keep - * coming back to reclaim from this cgroup - */ - if (total >= (excess >> 2) || - (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) - break; - } - continue; - } - if (!mem_cgroup_reclaimable(victim, false)) - continue; - total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false, - zone, &nr_scanned); - *total_scanned += nr_scanned; - if (!res_counter_soft_limit_excess(&root_memcg->res)) +/* + * A group is eligible for the soft limit reclaim under the given root + * 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, + struct mem_cgroup *root) +{ + struct mem_cgroup *parent; + + if (!memcg) + memcg = root_mem_cgroup; + parent = memcg; + + if (res_counter_soft_limit_excess(&memcg->res)) + return VISIT; + + /* + * If any parent up to the root in the hierarchy is over its soft limit + * then we have to obey and reclaim from this group as well. + */ + while ((parent = parent_mem_cgroup(parent))) { + if (res_counter_soft_limit_excess(&parent->res)) + return VISIT; + if (parent == root) break; } - mem_cgroup_iter_break(root_memcg, victim); - return total; + + if (!atomic_read(&memcg->children_in_excess)) + return SKIP_TREE; + return SKIP; } +static DEFINE_SPINLOCK(memcg_oom_lock); + /* * Check OOM-Killer is already running under our hierarchy. * If someone is running, return false. - * Has to be called with memcg_oom_lock */ -static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg) +static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg) { struct mem_cgroup *iter, *failed = NULL; + spin_lock(&memcg_oom_lock); + for_each_mem_cgroup_tree(iter, memcg) { if (iter->oom_lock) { /* @@ -2079,33 +1928,33 @@ static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg) iter->oom_lock = true; } - if (!failed) - return true; - - /* - * OK, we failed to lock the whole subtree so we have to clean up - * what we set up to the failing subtree - */ - for_each_mem_cgroup_tree(iter, memcg) { - if (iter == failed) { - mem_cgroup_iter_break(memcg, iter); - break; + if (failed) { + /* + * OK, we failed to lock the whole subtree so we have + * to clean up what we set up to the failing subtree + */ + for_each_mem_cgroup_tree(iter, memcg) { + if (iter == failed) { + mem_cgroup_iter_break(memcg, iter); + break; + } + iter->oom_lock = false; } - iter->oom_lock = false; } - return false; + + spin_unlock(&memcg_oom_lock); + + return !failed; } -/* - * Has to be called with memcg_oom_lock - */ -static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg) +static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg) { struct mem_cgroup *iter; + spin_lock(&memcg_oom_lock); for_each_mem_cgroup_tree(iter, memcg) iter->oom_lock = false; - return 0; + spin_unlock(&memcg_oom_lock); } static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg) @@ -2129,7 +1978,6 @@ static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg) atomic_add_unless(&iter->under_oom, -1, 0); } -static DEFINE_SPINLOCK(memcg_oom_lock); static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); struct oom_wait_info { @@ -2159,6 +2007,7 @@ static int memcg_oom_wake_function(wait_queue_t *wait, static void memcg_wakeup_oom(struct mem_cgroup *memcg) { + atomic_inc(&memcg->oom_wakeups); /* for filtering, pass "memcg" as argument. */ __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); } @@ -2170,56 +2019,136 @@ static void memcg_oom_recover(struct mem_cgroup *memcg) } /* - * try to call OOM killer. returns false if we should exit memory-reclaim loop. + * try to call OOM killer */ -static bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask, - int order) +static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) { - struct oom_wait_info owait; - bool locked, need_to_kill; + bool locked; + int wakeups; - owait.memcg = memcg; - owait.wait.flags = 0; - owait.wait.func = memcg_oom_wake_function; - owait.wait.private = current; - INIT_LIST_HEAD(&owait.wait.task_list); - need_to_kill = true; - mem_cgroup_mark_under_oom(memcg); + if (!current->memcg_oom.may_oom) + return; + + current->memcg_oom.in_memcg_oom = 1; - /* At first, try to OOM lock hierarchy under memcg.*/ - spin_lock(&memcg_oom_lock); - locked = mem_cgroup_oom_lock(memcg); /* - * Even if signal_pending(), we can't quit charge() loop without - * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL - * under OOM is always welcomed, use TASK_KILLABLE here. + * As with any blocking lock, a contender needs to start + * listening for wakeups before attempting the trylock, + * otherwise it can miss the wakeup from the unlock and sleep + * indefinitely. This is just open-coded because our locking + * is so particular to memcg hierarchies. */ - prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); - if (!locked || memcg->oom_kill_disable) - need_to_kill = false; + wakeups = atomic_read(&memcg->oom_wakeups); + mem_cgroup_mark_under_oom(memcg); + + locked = mem_cgroup_oom_trylock(memcg); + if (locked) mem_cgroup_oom_notify(memcg); - spin_unlock(&memcg_oom_lock); - if (need_to_kill) { - finish_wait(&memcg_oom_waitq, &owait.wait); + if (locked && !memcg->oom_kill_disable) { + mem_cgroup_unmark_under_oom(memcg); mem_cgroup_out_of_memory(memcg, mask, order); + mem_cgroup_oom_unlock(memcg); + /* + * There is no guarantee that an OOM-lock contender + * sees the wakeups triggered by the OOM kill + * uncharges. Wake any sleepers explicitely. + */ + memcg_oom_recover(memcg); } else { - schedule(); - finish_wait(&memcg_oom_waitq, &owait.wait); + /* + * A system call can just return -ENOMEM, but if this + * is a page fault and somebody else is handling the + * OOM already, we need to sleep on the OOM waitqueue + * for this memcg until the situation is resolved. + * Which can take some time because it might be + * handled by a userspace task. + * + * However, this is the charge context, which means + * that we may sit on a large call stack and hold + * various filesystem locks, the mmap_sem etc. and we + * don't want the OOM handler to deadlock on them + * while we sit here and wait. Store the current OOM + * context in the task_struct, then return -ENOMEM. + * At the end of the page fault handler, with the + * stack unwound, pagefault_out_of_memory() will check + * back with us by calling + * mem_cgroup_oom_synchronize(), possibly putting the + * task to sleep. + */ + current->memcg_oom.oom_locked = locked; + current->memcg_oom.wakeups = wakeups; + css_get(&memcg->css); + current->memcg_oom.wait_on_memcg = memcg; } - spin_lock(&memcg_oom_lock); - if (locked) - mem_cgroup_oom_unlock(memcg); - memcg_wakeup_oom(memcg); - spin_unlock(&memcg_oom_lock); +} - mem_cgroup_unmark_under_oom(memcg); +/** + * mem_cgroup_oom_synchronize - complete memcg OOM handling + * + * This has to be called at the end of a page fault if the the memcg + * OOM handler was enabled and the fault is returning %VM_FAULT_OOM. + * + * Memcg supports userspace OOM handling, so failed allocations must + * sleep on a waitqueue until the userspace task resolves the + * situation. Sleeping directly in the charge context with all kinds + * of locks held is not a good idea, instead we remember an OOM state + * in the task and mem_cgroup_oom_synchronize() has to be called at + * the end of the page fault to put the task to sleep and clean up the + * OOM state. + * + * Returns %true if an ongoing memcg OOM situation was detected and + * finalized, %false otherwise. + */ +bool mem_cgroup_oom_synchronize(void) +{ + struct oom_wait_info owait; + struct mem_cgroup *memcg; - if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) + /* OOM is global, do not handle */ + if (!current->memcg_oom.in_memcg_oom) return false; - /* Give chance to dying process */ - schedule_timeout_uninterruptible(1); + + /* + * We invoked the OOM killer but there is a chance that a kill + * did not free up any charges. Everybody else might already + * be sleeping, so restart the fault and keep the rampage + * going until some charges are released. + */ + memcg = current->memcg_oom.wait_on_memcg; + if (!memcg) + goto out; + + if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) + goto out_memcg; + + owait.memcg = memcg; + owait.wait.flags = 0; + owait.wait.func = memcg_oom_wake_function; + owait.wait.private = current; + INIT_LIST_HEAD(&owait.wait.task_list); + + prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); + /* Only sleep if we didn't miss any wakeups since OOM */ + if (atomic_read(&memcg->oom_wakeups) == current->memcg_oom.wakeups) + schedule(); + finish_wait(&memcg_oom_waitq, &owait.wait); +out_memcg: + mem_cgroup_unmark_under_oom(memcg); + if (current->memcg_oom.oom_locked) { + mem_cgroup_oom_unlock(memcg); + /* + * There is no guarantee that an OOM-lock contender + * sees the wakeups triggered by the OOM kill + * uncharges. Wake any sleepers explicitely. + */ + memcg_oom_recover(memcg); + } + css_put(&memcg->css); + current->memcg_oom.wait_on_memcg = NULL; +out: + current->memcg_oom.in_memcg_oom = 0; return true; } @@ -2288,7 +2217,7 @@ void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags) } void mem_cgroup_update_page_stat(struct page *page, - enum mem_cgroup_page_stat_item idx, int val) + enum mem_cgroup_stat_index idx, int val) { struct mem_cgroup *memcg; struct page_cgroup *pc = lookup_page_cgroup(page); @@ -2297,18 +2226,11 @@ void mem_cgroup_update_page_stat(struct page *page, if (mem_cgroup_disabled()) return; + VM_BUG_ON(!rcu_read_lock_held()); memcg = pc->mem_cgroup; if (unlikely(!memcg || !PageCgroupUsed(pc))) return; - switch (idx) { - case MEMCG_NR_FILE_MAPPED: - idx = MEM_CGROUP_STAT_FILE_MAPPED; - break; - default: - BUG(); - } - this_cpu_add(memcg->stat->count[idx], val); } @@ -2450,7 +2372,7 @@ static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync) flush_work(&stock->work); } out: - put_online_cpus(); + put_online_cpus(); } /* @@ -2532,12 +2454,11 @@ enum { CHARGE_RETRY, /* need to retry but retry is not bad */ CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ - CHARGE_OOM_DIE, /* the current is killed because of OOM */ }; static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, unsigned int nr_pages, unsigned int min_pages, - bool oom_check) + bool invoke_oom) { unsigned long csize = nr_pages * PAGE_SIZE; struct mem_cgroup *mem_over_limit; @@ -2594,14 +2515,10 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, if (mem_cgroup_wait_acct_move(mem_over_limit)) return CHARGE_RETRY; - /* If we don't need to call oom-killer at el, return immediately */ - if (!oom_check) - return CHARGE_NOMEM; - /* check OOM */ - if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize))) - return CHARGE_OOM_DIE; + if (invoke_oom) + mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(csize)); - return CHARGE_RETRY; + return CHARGE_NOMEM; } /* @@ -2704,7 +2621,7 @@ again: } do { - bool oom_check; + bool invoke_oom = oom && !nr_oom_retries; /* If killed, bypass charge */ if (fatal_signal_pending(current)) { @@ -2712,14 +2629,8 @@ again: goto bypass; } - oom_check = false; - if (oom && !nr_oom_retries) { - oom_check = true; - nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; - } - - ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, nr_pages, - oom_check); + ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, + nr_pages, invoke_oom); switch (ret) { case CHARGE_OK: break; @@ -2732,16 +2643,12 @@ again: css_put(&memcg->css); goto nomem; case CHARGE_NOMEM: /* OOM routine works */ - if (!oom) { + if (!oom || invoke_oom) { css_put(&memcg->css); goto nomem; } - /* If oom, we never return -ENOMEM */ nr_oom_retries--; break; - case CHARGE_OOM_DIE: /* Killed by OOM Killer */ - css_put(&memcg->css); - goto bypass; } } while (ret != CHARGE_OK); @@ -2882,7 +2789,7 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, * is accessed after testing USED bit. To make pc->mem_cgroup visible * before USED bit, we need memory barrier here. * See mem_cgroup_add_lru_list(), etc. - */ + */ smp_wmb(); SetPageCgroupUsed(pc); @@ -2905,9 +2812,7 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, unlock_page_cgroup(pc); /* - * "charge_statistics" updated event counter. Then, check it. - * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. - * if they exceeds softlimit. + * "charge_statistics" updated event counter. */ memcg_check_events(memcg, page); } @@ -3626,9 +3531,9 @@ __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order) * the page allocator. Therefore, the following sequence when backed by * the SLUB allocator: * - * memcg_stop_kmem_account(); - * kmalloc(<large_number>) - * memcg_resume_kmem_account(); + * memcg_stop_kmem_account(); + * kmalloc(<large_number>) + * memcg_resume_kmem_account(); * * would effectively ignore the fact that we should skip accounting, * since it will drive us directly to this function without passing @@ -3750,6 +3655,20 @@ void mem_cgroup_split_huge_fixup(struct page *head) } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ +static inline +void mem_cgroup_move_account_page_stat(struct mem_cgroup *from, + struct mem_cgroup *to, + unsigned int nr_pages, + enum mem_cgroup_stat_index idx) +{ + /* Update stat data for mem_cgroup */ + preempt_disable(); + WARN_ON_ONCE(from->stat->count[idx] < nr_pages); + __this_cpu_add(from->stat->count[idx], -nr_pages); + __this_cpu_add(to->stat->count[idx], nr_pages); + preempt_enable(); +} + /** * mem_cgroup_move_account - move account of the page * @page: the page @@ -3795,13 +3714,14 @@ static int mem_cgroup_move_account(struct page *page, move_lock_mem_cgroup(from, &flags); - if (!anon && page_mapped(page)) { - /* Update mapped_file data for mem_cgroup */ - preempt_disable(); - __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); - __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); - preempt_enable(); - } + if (!anon && page_mapped(page)) + mem_cgroup_move_account_page_stat(from, to, nr_pages, + MEM_CGROUP_STAT_FILE_MAPPED); + + if (PageWriteback(page)) + mem_cgroup_move_account_page_stat(from, to, nr_pages, + MEM_CGROUP_STAT_WRITEBACK); + mem_cgroup_charge_statistics(from, page, anon, -nr_pages); /* caller should have done css_get */ @@ -4657,7 +4577,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, MEM_CGROUP_RECLAIM_SHRINK); curusage = res_counter_read_u64(&memcg->res, RES_USAGE); /* Usage is reduced ? */ - if (curusage >= oldusage) + if (curusage >= oldusage) retry_count--; else oldusage = curusage; @@ -4678,7 +4598,7 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, int enlarge = 0; /* see mem_cgroup_resize_res_limit */ - retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; + retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); while (retry_count) { if (signal_pending(current)) { @@ -4727,98 +4647,6 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, return ret; } -unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, - gfp_t gfp_mask, - unsigned long *total_scanned) -{ - unsigned long nr_reclaimed = 0; - struct mem_cgroup_per_zone *mz, *next_mz = NULL; - unsigned long reclaimed; - int loop = 0; - struct mem_cgroup_tree_per_zone *mctz; - unsigned long long excess; - unsigned long nr_scanned; - - if (order > 0) - return 0; - - mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone)); - /* - * This loop can run a while, specially if mem_cgroup's continuously - * keep exceeding their soft limit and putting the system under - * pressure - */ - do { - if (next_mz) - mz = next_mz; - else - mz = mem_cgroup_largest_soft_limit_node(mctz); - if (!mz) - break; - - nr_scanned = 0; - reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone, - gfp_mask, &nr_scanned); - nr_reclaimed += reclaimed; - *total_scanned += nr_scanned; - spin_lock(&mctz->lock); - - /* - * If we failed to reclaim anything from this memory cgroup - * it is time to move on to the next cgroup - */ - next_mz = NULL; - if (!reclaimed) { - do { - /* - * Loop until we find yet another one. - * - * By the time we get the soft_limit lock - * again, someone might have aded the - * group back on the RB tree. Iterate to - * make sure we get a different mem. - * mem_cgroup_largest_soft_limit_node returns - * NULL if no other cgroup is present on - * the tree - */ - next_mz = - __mem_cgroup_largest_soft_limit_node(mctz); - if (next_mz == mz) - css_put(&next_mz->memcg->css); - else /* next_mz == NULL or other memcg */ - break; - } while (1); - } - __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz); - excess = res_counter_soft_limit_excess(&mz->memcg->res); - /* - * One school of thought says that we should not add - * back the node to the tree if reclaim returns 0. - * But our reclaim could return 0, simply because due - * to priority we are exposing a smaller subset of - * memory to reclaim from. Consider this as a longer - * term TODO. - */ - /* If excess == 0, no tree ops */ - __mem_cgroup_insert_exceeded(mz->memcg, mz, mctz, excess); - spin_unlock(&mctz->lock); - css_put(&mz->memcg->css); - loop++; - /* - * Could not reclaim anything and there are no more - * mem cgroups to try or we seem to be looping without - * reclaiming anything. - */ - if (!nr_reclaimed && - (next_mz == NULL || - loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) - break; - } while (!nr_reclaimed); - if (next_mz) - css_put(&next_mz->memcg->css); - return nr_reclaimed; -} - /** * mem_cgroup_force_empty_list - clears LRU of a group * @memcg: group to clear @@ -4990,18 +4818,12 @@ static int mem_cgroup_force_empty_write(struct cgroup_subsys_state *css, unsigned int event) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); - int ret; if (mem_cgroup_is_root(memcg)) return -EINVAL; - css_get(&memcg->css); - ret = mem_cgroup_force_empty(memcg); - css_put(&memcg->css); - - return ret; + return mem_cgroup_force_empty(memcg); } - static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css, struct cftype *cft) { @@ -5139,7 +4961,7 @@ static int memcg_update_kmem_limit(struct cgroup_subsys_state *css, u64 val) */ mutex_lock(&memcg_create_mutex); mutex_lock(&set_limit_mutex); - if (!memcg->kmem_account_flags && val != RESOURCE_MAX) { + if (!memcg->kmem_account_flags && val != RES_COUNTER_MAX) { if (cgroup_task_count(css->cgroup) || memcg_has_children(memcg)) { ret = -EBUSY; goto out; @@ -5149,7 +4971,7 @@ static int memcg_update_kmem_limit(struct cgroup_subsys_state *css, u64 val) ret = memcg_update_cache_sizes(memcg); if (ret) { - res_counter_set_limit(&memcg->kmem, RESOURCE_MAX); + res_counter_set_limit(&memcg->kmem, RES_COUNTER_MAX); goto out; } static_key_slow_inc(&memcg_kmem_enabled_key); @@ -6089,8 +5911,6 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) for (zone = 0; zone < MAX_NR_ZONES; zone++) { mz = &pn->zoneinfo[zone]; lruvec_init(&mz->lruvec); - mz->usage_in_excess = 0; - mz->on_tree = false; mz->memcg = memcg; } memcg->nodeinfo[node] = pn; @@ -6146,7 +5966,6 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) int node; size_t size = memcg_size(); - mem_cgroup_remove_from_trees(memcg); free_css_id(&mem_cgroup_subsys, &memcg->css); for_each_node(node) @@ -6183,29 +6002,6 @@ struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg) } EXPORT_SYMBOL(parent_mem_cgroup); -static void __init mem_cgroup_soft_limit_tree_init(void) -{ - struct mem_cgroup_tree_per_node *rtpn; - struct mem_cgroup_tree_per_zone *rtpz; - int tmp, node, zone; - - for_each_node(node) { - tmp = node; - if (!node_state(node, N_NORMAL_MEMORY)) - tmp = -1; - rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); - BUG_ON(!rtpn); - - soft_limit_tree.rb_tree_per_node[node] = rtpn; - - for (zone = 0; zone < MAX_NR_ZONES; zone++) { - rtpz = &rtpn->rb_tree_per_zone[zone]; - rtpz->rb_root = RB_ROOT; - spin_lock_init(&rtpz->lock); - } - } -} - static struct cgroup_subsys_state * __ref mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { @@ -6235,6 +6031,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) mutex_init(&memcg->thresholds_lock); spin_lock_init(&memcg->move_lock); vmpressure_init(&memcg->vmpressure); + spin_lock_init(&memcg->soft_lock); return &memcg->css; @@ -6312,6 +6109,13 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) 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); + + if (memcg != root_mem_cgroup && !root_mem_cgroup->use_hierarchy) + atomic_dec(&root_mem_cgroup->children_in_excess); + } mem_cgroup_destroy_all_caches(memcg); vmpressure_cleanup(&memcg->vmpressure); } @@ -6986,7 +6790,6 @@ static int __init mem_cgroup_init(void) { hotcpu_notifier(memcg_cpu_hotplug_callback, 0); enable_swap_cgroup(); - mem_cgroup_soft_limit_tree_init(); memcg_stock_init(); return 0; } |
