#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>
#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",
};
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 */
};
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;
bool oom_lock;
atomic_t under_oom;
+ atomic_t oom_wakeups;
int swappiness;
/* OOM-Killer disable */
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 */
* 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,
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.
*
return false;
}
-/*
- * 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.
*
mem_cgroup_threshold(memcg);
if (unlikely(do_softlimit))
- mem_cgroup_update_soft_limit(memcg);
+ mem_cgroup_update_tree(memcg, page);
#if MAX_NUMNODES > 1
if (unlikely(do_numainfo))
atomic_inc(&memcg->numainfo_events);
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.
* 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;
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;
}
}
* @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.
* 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;
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();
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);
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:
return total;
}
-#if MAX_NUMNODES > 1
/**
* test_mem_cgroup_node_reclaimable
* @memcg: the target memcg
return false;
}
+#if MAX_NUMNODES > 1
/*
* Always updating the nodemask is not very good - even if we have an empty
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;
}
-#endif
-
-/*
- * 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)
+static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
{
- struct mem_cgroup *parent;
-
- if (!memcg)
- memcg = root_mem_cgroup;
- parent = memcg;
-
- if (res_counter_soft_limit_excess(&memcg->res))
- return VISIT;
+ return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
+}
+#endif
- /*
- * 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)
+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))
break;
}
-
- if (!atomic_read(&memcg->children_in_excess))
- return SKIP_TREE;
- return SKIP;
+ mem_cgroup_iter_break(root_memcg, victim);
+ return total;
}
+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) {
/*
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)
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 {
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);
}
}
/*
- * 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;
}
}
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);
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);
}
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;
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 || !current->memcg_oom.may_oom)
- 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;
}
/*
}
do {
- bool oom_check;
+ bool invoke_oom = oom && !nr_oom_retries;
/* If killed, bypass charge */
if (fatal_signal_pending(current)) {
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;
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);
unlock_page_cgroup(pc);
/*
- * "charge_statistics" updated event counter.
+ * "charge_statistics" updated event counter. Then, check it.
+ * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
+ * if they exceeds softlimit.
*/
memcg_check_events(memcg, page);
}
}
#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
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 */
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
*/
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;
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);
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;
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)
}
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)
{
mutex_init(&memcg->thresholds_lock);
spin_lock_init(&memcg->move_lock);
vmpressure_init(&memcg->vmpressure);
- spin_lock_init(&memcg->soft_lock);
return &memcg->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);
}
{
hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
enable_swap_cgroup();
+ mem_cgroup_soft_limit_tree_init();
memcg_stock_init();
return 0;
}
git.openpandora.org / pandora-kernel.git / blobdiff