/* memcontrol.c - Memory Controller * * Copyright IBM Corporation, 2007 * Author Balbir Singh <balbir@linux.vnet.ibm.com> * * Copyright 2007 OpenVZ SWsoft Inc * Author: Pavel Emelianov <xemul@openvz.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/res_counter.h> #include <linux/memcontrol.h> #include <linux/cgroup.h> #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/smp.h> #include <linux/page-flags.h> #include <linux/backing-dev.h> #include <linux/bit_spinlock.h> #include <linux/rcupdate.h> #include <linux/limits.h> #include <linux/mutex.h> #include <linux/slab.h> #include <linux/swap.h> #include <linux/spinlock.h> #include <linux/fs.h> #include <linux/seq_file.h> #include <linux/vmalloc.h> #include <linux/mm_inline.h> #include <linux/page_cgroup.h> #include "internal.h" #include <asm/uaccess.h> struct cgroup_subsys mem_cgroup_subsys __read_mostly; #define MEM_CGROUP_RECLAIM_RETRIES 5 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP /* Turned on only when memory cgroup is enabled && really_do_swap_account = 0 */ int do_swap_account __read_mostly; static int really_do_swap_account __initdata = 1; /* for remember boot option*/ #else #define do_swap_account (0) #endif static DEFINE_MUTEX(memcg_tasklist); /* can be hold under cgroup_mutex */ /* * 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 rss */ MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */ MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */ MEM_CGROUP_STAT_NSTATS, }; struct mem_cgroup_stat_cpu { s64 count[MEM_CGROUP_STAT_NSTATS]; } ____cacheline_aligned_in_smp; struct mem_cgroup_stat { struct mem_cgroup_stat_cpu cpustat[0]; }; /* * For accounting under irq disable, no need for increment preempt count. */ static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat, enum mem_cgroup_stat_index idx, int val) { stat->count[idx] += val; } static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat, enum mem_cgroup_stat_index idx) { int cpu; s64 ret = 0; for_each_possible_cpu(cpu) ret += stat->cpustat[cpu].count[idx]; return ret; } static s64 mem_cgroup_local_usage(struct mem_cgroup_stat *stat) { s64 ret; ret = mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_CACHE); ret += mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_RSS); return ret; } /* * per-zone information in memory controller. */ struct mem_cgroup_per_zone { /* * spin_lock to protect the per cgroup LRU */ struct list_head lists[NR_LRU_LISTS]; unsigned long count[NR_LRU_LISTS]; struct zone_reclaim_stat reclaim_stat; }; /* Macro for accessing counter */ #define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)]) struct mem_cgroup_per_node { struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; }; struct mem_cgroup_lru_info { struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES]; }; /* * The memory controller data structure. The memory controller controls both * page cache and RSS per cgroup. We would eventually like to provide * statistics based on the statistics developed by Rik Van Riel for clock-pro, * to help the administrator determine what knobs to tune. * * TODO: Add a water mark for the memory controller. Reclaim will begin when * we hit the water mark. May be even add a low water mark, such that * no reclaim occurs from a cgroup at it's low water mark, this is * a feature that will be implemented much later in the future. */ struct mem_cgroup { struct cgroup_subsys_state css; /* * the counter to account for memory usage */ struct res_counter res; /* * the counter to account for mem+swap usage. */ struct res_counter memsw; /* * Per cgroup active and inactive list, similar to the * per zone LRU lists. */ struct mem_cgroup_lru_info info; /* protect against reclaim related member. */ spinlock_t reclaim_param_lock; int prev_priority; /* for recording reclaim priority */ /* * While reclaiming in a hiearchy, we cache the last child we * reclaimed from. */ int last_scanned_child; /* * Should the accounting and control be hierarchical, per subtree? */ bool use_hierarchy; unsigned long last_oom_jiffies; atomic_t refcnt; unsigned int swappiness; /* * statistics. This must be placed at the end of memcg. */ struct mem_cgroup_stat stat; }; enum charge_type { MEM_CGROUP_CHARGE_TYPE_CACHE = 0, MEM_CGROUP_CHARGE_TYPE_MAPPED, MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ NR_CHARGE_TYPE, }; /* only for here (for easy reading.) */ #define PCGF_CACHE (1UL << PCG_CACHE) #define PCGF_USED (1UL << PCG_USED) #define PCGF_LOCK (1UL << PCG_LOCK) static const unsigned long pcg_default_flags[NR_CHARGE_TYPE] = { PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */ PCGF_USED | PCGF_LOCK, /* Anon */ PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */ 0, /* FORCE */ }; /* for encoding cft->private value on file */ #define _MEM (0) #define _MEMSWAP (1) #define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) #define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) #define MEMFILE_ATTR(val) ((val) & 0xffff) static void mem_cgroup_get(struct mem_cgroup *mem); static void mem_cgroup_put(struct mem_cgroup *mem); static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem); static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, struct page_cgroup *pc, bool charge) { int val = (charge)? 1 : -1; struct mem_cgroup_stat *stat = &mem->stat; struct mem_cgroup_stat_cpu *cpustat; int cpu = get_cpu(); cpustat = &stat->cpustat[cpu]; if (PageCgroupCache(pc)) __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val); else __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val); if (charge) __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_PGPGIN_COUNT, 1); else __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_PGPGOUT_COUNT, 1); put_cpu(); } static struct mem_cgroup_per_zone * mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid) { return &mem->info.nodeinfo[nid]->zoneinfo[zid]; } static struct mem_cgroup_per_zone * page_cgroup_zoneinfo(struct page_cgroup *pc) { struct mem_cgroup *mem = pc->mem_cgroup; int nid = page_cgroup_nid(pc); int zid = page_cgroup_zid(pc); if (!mem) return NULL; return mem_cgroup_zoneinfo(mem, nid, zid); } static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem, enum lru_list idx) { int nid, zid; struct mem_cgroup_per_zone *mz; u64 total = 0; for_each_online_node(nid) for (zid = 0; zid < MAX_NR_ZONES; zid++) { mz = mem_cgroup_zoneinfo(mem, nid, zid); total += MEM_CGROUP_ZSTAT(mz, idx); } return total; } static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) { return container_of(cgroup_subsys_state(cont, mem_cgroup_subsys_id), struct mem_cgroup, css); } struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) { /* * mm_update_next_owner() may clear mm->owner to NULL * if it races with swapoff, page migration, etc. * So this can be called with p == NULL. */ if (unlikely(!p)) return NULL; return container_of(task_subsys_state(p, mem_cgroup_subsys_id), struct mem_cgroup, css); } static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) { struct mem_cgroup *mem = NULL; if (!mm) return NULL; /* * Because we have no locks, mm->owner's may be being moved to other * cgroup. We use css_tryget() here even if this looks * pessimistic (rather than adding locks here). */ rcu_read_lock(); do { mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); if (unlikely(!mem)) break; } while (!css_tryget(&mem->css)); rcu_read_unlock(); return mem; } /* * Call callback function against all cgroup under hierarchy tree. */ static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data, int (*func)(struct mem_cgroup *, void *)) { int found, ret, nextid; struct cgroup_subsys_state *css; struct mem_cgroup *mem; if (!root->use_hierarchy) return (*func)(root, data); nextid = 1; do { ret = 0; mem = NULL; rcu_read_lock(); css = css_get_next(&mem_cgroup_subsys, nextid, &root->css, &found); if (css && css_tryget(css)) mem = container_of(css, struct mem_cgroup, css); rcu_read_unlock(); if (mem) { ret = (*func)(mem, data); css_put(&mem->css); } nextid = found + 1; } while (!ret && css); return ret; } /* * Following LRU functions are allowed to be used without PCG_LOCK. * Operations are called by routine of global LRU independently from memcg. * What we have to take care of here is validness of pc->mem_cgroup. * * Changes to pc->mem_cgroup happens when * 1. charge * 2. moving account * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. * It is added to LRU before charge. * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. * When moving account, the page is not on LRU. It's isolated. */ void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru) { struct page_cgroup *pc; struct mem_cgroup *mem; struct mem_cgroup_per_zone *mz; if (mem_cgroup_disabled()) return; pc = lookup_page_cgroup(page); /* can happen while we handle swapcache. */ if (list_empty(&pc->lru) || !pc->mem_cgroup) return; /* * We don't check PCG_USED bit. It's cleared when the "page" is finally * removed from global LRU. */ mz = page_cgroup_zoneinfo(pc); mem = pc->mem_cgroup; MEM_CGROUP_ZSTAT(mz, lru) -= 1; list_del_init(&pc->lru); return; } void mem_cgroup_del_lru(struct page *page) { mem_cgroup_del_lru_list(page, page_lru(page)); } void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) { struct mem_cgroup_per_zone *mz; struct page_cgroup *pc; if (mem_cgroup_disabled()) return; pc = lookup_page_cgroup(page); /* * Used bit is set without atomic ops but after smp_wmb(). * For making pc->mem_cgroup visible, insert smp_rmb() here. */ smp_rmb(); /* unused page is not rotated. */ if (!PageCgroupUsed(pc)) return; mz = page_cgroup_zoneinfo(pc); list_move(&pc->lru, &mz->lists[lru]); } void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru) { struct page_cgroup *pc; struct mem_cgroup_per_zone *mz; if (mem_cgroup_disabled()) return; pc = lookup_page_cgroup(page); /* * Used bit is set without atomic ops but after smp_wmb(). * For making pc->mem_cgroup visible, insert smp_rmb() here. */ smp_rmb(); if (!PageCgroupUsed(pc)) return; mz = page_cgroup_zoneinfo(pc); MEM_CGROUP_ZSTAT(mz, lru) += 1; list_add(&pc->lru, &mz->lists[lru]); } /* * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to * lru because the page may.be reused after it's fully uncharged (because of * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge * it again. This function is only used to charge SwapCache. It's done under * lock_page and expected that zone->lru_lock is never held. */ static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page) { unsigned long flags; struct zone *zone = page_zone(page); struct page_cgroup *pc = lookup_page_cgroup(page); spin_lock_irqsave(&zone->lru_lock, flags); /* * Forget old LRU when this page_cgroup is *not* used. This Used bit * is guarded by lock_page() because the page is SwapCache. */ if (!PageCgroupUsed(pc)) mem_cgroup_del_lru_list(page, page_lru(page)); spin_unlock_irqrestore(&zone->lru_lock, flags); } static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page) { unsigned long flags; struct zone *zone = page_zone(page); struct page_cgroup *pc = lookup_page_cgroup(page); spin_lock_irqsave(&zone->lru_lock, flags); /* link when the page is linked to LRU but page_cgroup isn't */ if (PageLRU(page) && list_empty(&pc->lru)) mem_cgroup_add_lru_list(page, page_lru(page)); spin_unlock_irqrestore(&zone->lru_lock, flags); } void mem_cgroup_move_lists(struct page *page, enum lru_list from, enum lru_list to) { if (mem_cgroup_disabled()) return; mem_cgroup_del_lru_list(page, from); mem_cgroup_add_lru_list(page, to); } int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) { int ret; struct mem_cgroup *curr = NULL; task_lock(task); rcu_read_lock(); curr = try_get_mem_cgroup_from_mm(task->mm); rcu_read_unlock(); task_unlock(task); if (!curr) return 0; if (curr->use_hierarchy) ret = css_is_ancestor(&curr->css, &mem->css); else ret = (curr == mem); css_put(&curr->css); return ret; } /* * prev_priority control...this will be used in memory reclaim path. */ int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem) { int prev_priority; spin_lock(&mem->reclaim_param_lock); prev_priority = mem->prev_priority; spin_unlock(&mem->reclaim_param_lock); return prev_priority; } void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority) { spin_lock(&mem->reclaim_param_lock); if (priority < mem->prev_priority) mem->prev_priority = priority; spin_unlock(&mem->reclaim_param_lock); } void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority) { spin_lock(&mem->reclaim_param_lock); mem->prev_priority = priority; spin_unlock(&mem->reclaim_param_lock); } static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages) { unsigned long active; unsigned long inactive; unsigned long gb; unsigned long inactive_ratio; inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON); active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON); gb = (inactive + active) >> (30 - PAGE_SHIFT); if (gb) inactive_ratio = int_sqrt(10 * gb); else inactive_ratio = 1; if (present_pages) { present_pages[0] = inactive; present_pages[1] = active; } return inactive_ratio; } int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg) { unsigned long active; unsigned long inactive; unsigned long present_pages[2]; unsigned long inactive_ratio; inactive_ratio = calc_inactive_ratio(memcg, present_pages); inactive = present_pages[0]; active = present_pages[1]; if (inactive * inactive_ratio < active) return 1; return 0; } int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg) { unsigned long active; unsigned long inactive; inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE); active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE); return (active > inactive); } unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg, struct zone *zone, enum lru_list lru) { int nid = zone->zone_pgdat->node_id; int zid = zone_idx(zone); struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); return MEM_CGROUP_ZSTAT(mz, lru); } struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, struct zone *zone) { int nid = zone->zone_pgdat->node_id; int zid = zone_idx(zone); struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); return &mz->reclaim_stat; } struct zone_reclaim_stat * mem_cgroup_get_reclaim_stat_from_page(struct page *page) { struct page_cgroup *pc; struct mem_cgroup_per_zone *mz; if (mem_cgroup_disabled()) return NULL; pc = lookup_page_cgroup(page); /* * Used bit is set without atomic ops but after smp_wmb(). * For making pc->mem_cgroup visible, insert smp_rmb() here. */ smp_rmb(); if (!PageCgroupUsed(pc)) return NULL; mz = page_cgroup_zoneinfo(pc); if (!mz) return NULL; return &mz->reclaim_stat; } unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, struct list_head *dst, unsigned long *scanned, int order, int mode, struct zone *z, struct mem_cgroup *mem_cont, int active, int file) { unsigned long nr_taken = 0; struct page *page; unsigned long scan; LIST_HEAD(pc_list); struct list_head *src; struct page_cgroup *pc, *tmp; int nid = z->zone_pgdat->node_id; int zid = zone_idx(z); struct mem_cgroup_per_zone *mz; int lru = LRU_FILE * !!file + !!active; BUG_ON(!mem_cont); mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); src = &mz->lists[lru]; scan = 0; list_for_each_entry_safe_reverse(pc, tmp, src, lru) { if (scan >= nr_to_scan) break; page = pc->page; if (unlikely(!PageCgroupUsed(pc))) continue; if (unlikely(!PageLRU(page))) continue; scan++; if (__isolate_lru_page(page, mode, file) == 0) { list_move(&page->lru, dst); nr_taken++; } } *scanned = scan; return nr_taken; } #define mem_cgroup_from_res_counter(counter, member) \ container_of(counter, struct mem_cgroup, member) static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem) { if (do_swap_account) { if (res_counter_check_under_limit(&mem->res) && res_counter_check_under_limit(&mem->memsw)) return true; } else if (res_counter_check_under_limit(&mem->res)) return true; return false; } static unsigned int get_swappiness(struct mem_cgroup *memcg) { struct cgroup *cgrp = memcg->css.cgroup; unsigned int swappiness; /* root ? */ if (cgrp->parent == NULL) return vm_swappiness; spin_lock(&memcg->reclaim_param_lock); swappiness = memcg->swappiness; spin_unlock(&memcg->reclaim_param_lock); return swappiness; } static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data) { int *val = data; (*val)++; return 0; } /** * mem_cgroup_print_mem_info: Called from OOM with tasklist_lock held in read mode. * @memcg: The memory cgroup that went over limit * @p: Task that is going to be killed * * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is * enabled */ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) { struct cgroup *task_cgrp; struct cgroup *mem_cgrp; /* * Need a buffer in BSS, can't rely on allocations. The code relies * on the assumption that OOM is serialized for memory controller. * If this assumption is broken, revisit this code. */ static char memcg_name[PATH_MAX]; int ret; if (!memcg) return; rcu_read_lock(); mem_cgrp = memcg->css.cgroup; task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); if (ret < 0) { /* * Unfortunately, we are unable to convert to a useful name * But we'll still print out the usage information */ rcu_read_unlock(); goto done; } rcu_read_unlock(); printk(KERN_INFO "Task in %s killed", memcg_name); rcu_read_lock(); ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); if (ret < 0) { rcu_read_unlock(); goto done; } rcu_read_unlock(); /* * Continues from above, so we don't need an KERN_ level */ printk(KERN_CONT " as a result of limit of %s\n", memcg_name); done: printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, res_counter_read_u64(&memcg->res, RES_FAILCNT)); printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " "failcnt %llu\n", res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); } /* * This function returns the number of memcg under hierarchy tree. Returns * 1(self count) if no children. */ static int mem_cgroup_count_children(struct mem_cgroup *mem) { int num = 0; mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb); return num; } /* * 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_select_victim(struct mem_cgroup *root_mem) { struct mem_cgroup *ret = NULL; struct cgroup_subsys_state *css; int nextid, found; if (!root_mem->use_hierarchy) { css_get(&root_mem->css); ret = root_mem; } while (!ret) { rcu_read_lock(); nextid = root_mem->last_scanned_child + 1; css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css, &found); if (css && css_tryget(css)) ret = container_of(css, struct mem_cgroup, css); rcu_read_unlock(); /* Updates scanning parameter */ spin_lock(&root_mem->reclaim_param_lock); if (!css) { /* this means start scan from ID:1 */ root_mem->last_scanned_child = 0; } else root_mem->last_scanned_child = found; spin_unlock(&root_mem->reclaim_param_lock); } return ret; } /* * Scan 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. * * We give up and return to the caller when we visit root_mem twice. * (other groups can be removed while we're walking....) * * If shrink==true, for avoiding to free too much, this returns immedieately. */ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, gfp_t gfp_mask, bool noswap, bool shrink) { struct mem_cgroup *victim; int ret, total = 0; int loop = 0; while (loop < 2) { victim = mem_cgroup_select_victim(root_mem); if (victim == root_mem) loop++; if (!mem_cgroup_local_usage(&victim->stat)) { /* this cgroup's local usage == 0 */ css_put(&victim->css); continue; } /* we use swappiness of local cgroup */ ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, noswap, get_swappiness(victim)); css_put(&victim->css); /* * At shrinking usage, we can't check we should stop here or * reclaim more. It's depends on callers. last_scanned_child * will work enough for keeping fairness under tree. */ if (shrink) return ret; total += ret; if (mem_cgroup_check_under_limit(root_mem)) return 1 + total; } return total; } bool mem_cgroup_oom_called(struct task_struct *task) { bool ret = false; struct mem_cgroup *mem; struct mm_struct *mm; rcu_read_lock(); mm = task->mm; if (!mm) mm = &init_mm; mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10)) ret = true; rcu_read_unlock(); return ret; } static int record_last_oom_cb(struct mem_cgroup *mem, void *data) { mem->last_oom_jiffies = jiffies; return 0; } static void record_last_oom(struct mem_cgroup *mem) { mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb); } /* * Unlike exported interface, "oom" parameter is added. if oom==true, * oom-killer can be invoked. */ static int __mem_cgroup_try_charge(struct mm_struct *mm, gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom) { struct mem_cgroup *mem, *mem_over_limit; int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; struct res_counter *fail_res; if (unlikely(test_thread_flag(TIF_MEMDIE))) { /* Don't account this! */ *memcg = NULL; return 0; } /* * We always charge the cgroup the mm_struct belongs to. * The mm_struct's mem_cgroup changes on task migration if the * thread group leader migrates. It's possible that mm is not * set, if so charge the init_mm (happens for pagecache usage). */ mem = *memcg; if (likely(!mem)) { mem = try_get_mem_cgroup_from_mm(mm); *memcg = mem; } else { css_get(&mem->css); } if (unlikely(!mem)) return 0; VM_BUG_ON(css_is_removed(&mem->css)); while (1) { int ret; bool noswap = false; ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res); if (likely(!ret)) { if (!do_swap_account) break; ret = res_counter_charge(&mem->memsw, PAGE_SIZE, &fail_res); if (likely(!ret)) break; /* 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; ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask, noswap, false); if (ret) continue; /* * try_to_free_mem_cgroup_pages() might not give us a full * picture of reclaim. Some pages are reclaimed and might be * moved to swap cache or just unmapped from the cgroup. * Check the limit again to see if the reclaim reduced the * current usage of the cgroup before giving up * */ if (mem_cgroup_check_under_limit(mem_over_limit)) continue; if (!nr_retries--) { if (oom) { mutex_lock(&memcg_tasklist); mem_cgroup_out_of_memory(mem_over_limit, gfp_mask); mutex_unlock(&memcg_tasklist); record_last_oom(mem_over_limit); } goto nomem; } } return 0; nomem: css_put(&mem->css); return -ENOMEM; } /* * A helper function to get mem_cgroup from ID. must be called under * rcu_read_lock(). The caller must check css_is_removed() or some if * it's concern. (dropping refcnt from swap can be called against removed * memcg.) */ static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) { struct cgroup_subsys_state *css; /* ID 0 is unused ID */ if (!id) return NULL; css = css_lookup(&mem_cgroup_subsys, id); if (!css) return NULL; return container_of(css, struct mem_cgroup, css); } static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page) { struct mem_cgroup *mem; struct page_cgroup *pc; unsigned short id; swp_entry_t ent; VM_BUG_ON(!PageLocked(page)); if (!PageSwapCache(page)) return NULL; pc = lookup_page_cgroup(page); lock_page_cgroup(pc); if (PageCgroupUsed(pc)) { mem = pc->mem_cgroup; if (mem && !css_tryget(&mem->css)) mem = NULL; } else { ent.val = page_private(page); id = lookup_swap_cgroup(ent); rcu_read_lock(); mem = mem_cgroup_lookup(id); if (mem && !css_tryget(&mem->css)) mem = NULL; rcu_read_unlock(); } unlock_page_cgroup(pc); return mem; } /* * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be * USED state. If already USED, uncharge and return. */ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem, struct page_cgroup *pc, enum charge_type ctype) { /* try_charge() can return NULL to *memcg, taking care of it. */ if (!mem) return; lock_page_cgroup(pc); if (unlikely(PageCgroupUsed(pc))) { unlock_page_cgroup(pc); res_counter_uncharge(&mem->res, PAGE_SIZE); if (do_swap_account) res_counter_uncharge(&mem->memsw, PAGE_SIZE); css_put(&mem->css); return; } pc->mem_cgroup = mem; smp_wmb(); pc->flags = pcg_default_flags[ctype]; mem_cgroup_charge_statistics(mem, pc, true); unlock_page_cgroup(pc); } /** * mem_cgroup_move_account - move account of the page * @pc: page_cgroup of the page. * @from: mem_cgroup which the page is moved from. * @to: mem_cgroup which the page is moved to. @from != @to. * * The caller must confirm following. * - page is not on LRU (isolate_page() is useful.) * * returns 0 at success, * returns -EBUSY when lock is busy or "pc" is unstable. * * This function does "uncharge" from old cgroup but doesn't do "charge" to * new cgroup. It should be done by a caller. */ static int mem_cgroup_move_account(struct page_cgroup *pc, struct mem_cgroup *from, struct mem_cgroup *to) { struct mem_cgroup_per_zone *from_mz, *to_mz; int nid, zid; int ret = -EBUSY; VM_BUG_ON(from == to); VM_BUG_ON(PageLRU(pc->page)); nid = page_cgroup_nid(pc); zid = page_cgroup_zid(pc); from_mz = mem_cgroup_zoneinfo(from, nid, zid); to_mz = mem_cgroup_zoneinfo(to, nid, zid); if (!trylock_page_cgroup(pc)) return ret; if (!PageCgroupUsed(pc)) goto out; if (pc->mem_cgroup != from) goto out; res_counter_uncharge(&from->res, PAGE_SIZE); mem_cgroup_charge_statistics(from, pc, false); if (do_swap_account) res_counter_uncharge(&from->memsw, PAGE_SIZE); css_put(&from->css); css_get(&to->css); pc->mem_cgroup = to; mem_cgroup_charge_statistics(to, pc, true); ret = 0; out: unlock_page_cgroup(pc); return ret; } /* * move charges to its parent. */ static int mem_cgroup_move_parent(struct page_cgroup *pc, struct mem_cgroup *child, gfp_t gfp_mask) { struct page *page = pc->page; struct cgroup *cg = child->css.cgroup; struct cgroup *pcg = cg->parent; struct mem_cgroup *parent; int ret; /* Is ROOT ? */ if (!pcg) return -EINVAL; parent = mem_cgroup_from_cont(pcg); ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false); if (ret || !parent) return ret; if (!get_page_unless_zero(page)) { ret = -EBUSY; goto uncharge; } ret = isolate_lru_page(page); if (ret) goto cancel; ret = mem_cgroup_move_account(pc, child, parent); putback_lru_page(page); if (!ret) { put_page(page); /* drop extra refcnt by try_charge() */ css_put(&parent->css); return 0; } cancel: put_page(page); uncharge: /* drop extra refcnt by try_charge() */ css_put(&parent->css); /* uncharge if move fails */ res_counter_uncharge(&parent->res, PAGE_SIZE); if (do_swap_account) res_counter_uncharge(&parent->memsw, PAGE_SIZE); return ret; } /* * Charge the memory controller for page usage. * Return * 0 if the charge was successful * < 0 if the cgroup is over its limit */ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, gfp_t gfp_mask, enum charge_type ctype, struct mem_cgroup *memcg) { struct mem_cgroup *mem; struct page_cgroup *pc; int ret; pc = lookup_page_cgroup(page); /* can happen at boot */ if (unlikely(!pc)) return 0; prefetchw(pc); mem = memcg; ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true); if (ret || !mem) return ret; __mem_cgroup_commit_charge(mem, pc, ctype); return 0; } int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { if (mem_cgroup_disabled()) return 0; if (PageCompound(page)) return 0; /* * If already mapped, we don't have to account. * If page cache, page->mapping has address_space. * But page->mapping may have out-of-use anon_vma pointer, * detecit it by PageAnon() check. newly-mapped-anon's page->mapping * is NULL. */ if (page_mapped(page) || (page->mapping && !PageAnon(page))) return 0; if (unlikely(!mm)) mm = &init_mm; return mem_cgroup_charge_common(page, mm, gfp_mask, MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL); } static void __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, enum charge_type ctype); int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { struct mem_cgroup *mem = NULL; int ret; if (mem_cgroup_disabled()) return 0; if (PageCompound(page)) return 0; /* * Corner case handling. This is called from add_to_page_cache() * in usual. But some FS (shmem) precharges this page before calling it * and call add_to_page_cache() with GFP_NOWAIT. * * For GFP_NOWAIT case, the page may be pre-charged before calling * add_to_page_cache(). (See shmem.c) check it here and avoid to call * charge twice. (It works but has to pay a bit larger cost.) * And when the page is SwapCache, it should take swap information * into account. This is under lock_page() now. */ if (!(gfp_mask & __GFP_WAIT)) { struct page_cgroup *pc; pc = lookup_page_cgroup(page); if (!pc) return 0; lock_page_cgroup(pc); if (PageCgroupUsed(pc)) { unlock_page_cgroup(pc); return 0; } unlock_page_cgroup(pc); } if (unlikely(!mm && !mem)) mm = &init_mm; if (page_is_file_cache(page)) return mem_cgroup_charge_common(page, mm, gfp_mask, MEM_CGROUP_CHARGE_TYPE_CACHE, NULL); /* shmem */ if (PageSwapCache(page)) { ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); if (!ret) __mem_cgroup_commit_charge_swapin(page, mem, MEM_CGROUP_CHARGE_TYPE_SHMEM); } else ret = mem_cgroup_charge_common(page, mm, gfp_mask, MEM_CGROUP_CHARGE_TYPE_SHMEM, mem); return ret; } /* * While swap-in, try_charge -> commit or cancel, the page is locked. * And when try_charge() successfully returns, one refcnt to memcg without * struct page_cgroup is aquired. This refcnt will be cumsumed by * "commit()" or removed by "cancel()" */ int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page, gfp_t mask, struct mem_cgroup **ptr) { struct mem_cgroup *mem; int ret; if (mem_cgroup_disabled()) return 0; if (!do_swap_account) goto charge_cur_mm; /* * A racing thread's fault, or swapoff, may have already updated * the pte, and even removed page from swap cache: return success * to go on to do_swap_page()'s pte_same() test, which should fail. */ if (!PageSwapCache(page)) return 0; mem = try_get_mem_cgroup_from_swapcache(page); if (!mem) goto charge_cur_mm; *ptr = mem; ret = __mem_cgroup_try_charge(NULL, mask, ptr, true); /* drop extra refcnt from tryget */ css_put(&mem->css); return ret; charge_cur_mm: if (unlikely(!mm)) mm = &init_mm; return __mem_cgroup_try_charge(mm, mask, ptr, true); } static void __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, enum charge_type ctype) { struct page_cgroup *pc; if (mem_cgroup_disabled()) return; if (!ptr) return; pc = lookup_page_cgroup(page); mem_cgroup_lru_del_before_commit_swapcache(page); __mem_cgroup_commit_charge(ptr, pc, ctype); mem_cgroup_lru_add_after_commit_swapcache(page); /* * Now swap is on-memory. This means this page may be * counted both as mem and swap....double count. * Fix it by uncharging from memsw. Basically, this SwapCache is stable * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() * may call delete_from_swap_cache() before reach here. */ if (do_swap_account && PageSwapCache(page)) { swp_entry_t ent = {.val = page_private(page)}; unsigned short id; struct mem_cgroup *memcg; id = swap_cgroup_record(ent, 0); rcu_read_lock(); memcg = mem_cgroup_lookup(id); if (memcg) { /* * This recorded memcg can be obsolete one. So, avoid * calling css_tryget */ res_counter_uncharge(&memcg->memsw, PAGE_SIZE); mem_cgroup_put(memcg); } rcu_read_unlock(); } /* add this page(page_cgroup) to the LRU we want. */ } void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) { __mem_cgroup_commit_charge_swapin(page, ptr, MEM_CGROUP_CHARGE_TYPE_MAPPED); } void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem) { if (mem_cgroup_disabled()) return; if (!mem) return; res_counter_uncharge(&mem->res, PAGE_SIZE); if (do_swap_account) res_counter_uncharge(&mem->memsw, PAGE_SIZE); css_put(&mem->css); } /* * uncharge if !page_mapped(page) */ static struct mem_cgroup * __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) { struct page_cgroup *pc; struct mem_cgroup *mem = NULL; struct mem_cgroup_per_zone *mz; if (mem_cgroup_disabled()) return NULL; if (PageSwapCache(page)) return NULL; /* * Check if our page_cgroup is valid */ pc = lookup_page_cgroup(page); if (unlikely(!pc || !PageCgroupUsed(pc))) return NULL; lock_page_cgroup(pc); mem = pc->mem_cgroup; if (!PageCgroupUsed(pc)) goto unlock_out; switch (ctype) { case MEM_CGROUP_CHARGE_TYPE_MAPPED: if (page_mapped(page)) goto unlock_out; break; case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: if (!PageAnon(page)) { /* Shared memory */ if (page->mapping && !page_is_file_cache(page)) goto unlock_out; } else if (page_mapped(page)) /* Anon */ goto unlock_out; break; default: break; } res_counter_uncharge(&mem->res, PAGE_SIZE); if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)) res_counter_uncharge(&mem->memsw, PAGE_SIZE); mem_cgroup_charge_statistics(mem, pc, false); ClearPageCgroupUsed(pc); /* * pc->mem_cgroup is not cleared here. It will be accessed when it's * freed from LRU. This is safe because uncharged page is expected not * to be reused (freed soon). Exception is SwapCache, it's handled by * special functions. */ mz = page_cgroup_zoneinfo(pc); unlock_page_cgroup(pc); /* at swapout, this memcg will be accessed to record to swap */ if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT) css_put(&mem->css); return mem; unlock_out: unlock_page_cgroup(pc); return NULL; } void mem_cgroup_uncharge_page(struct page *page) { /* early check. */ if (page_mapped(page)) return; if (page->mapping && !PageAnon(page)) return; __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); } void mem_cgroup_uncharge_cache_page(struct page *page) { VM_BUG_ON(page_mapped(page)); VM_BUG_ON(page->mapping); __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); } #ifdef CONFIG_SWAP /* * called after __delete_from_swap_cache() and drop "page" account. * memcg information is recorded to swap_cgroup of "ent" */ void mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent) { struct mem_cgroup *memcg; memcg = __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_SWAPOUT); /* record memcg information */ if (do_swap_account && memcg) { swap_cgroup_record(ent, css_id(&memcg->css)); mem_cgroup_get(memcg); } if (memcg) css_put(&memcg->css); } #endif #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP /* * called from swap_entry_free(). remove record in swap_cgroup and * uncharge "memsw" account. */ void mem_cgroup_uncharge_swap(swp_entry_t ent) { struct mem_cgroup *memcg; unsigned short id; if (!do_swap_account) return; id = swap_cgroup_record(ent, 0); rcu_read_lock(); memcg = mem_cgroup_lookup(id); if (memcg) { /* * We uncharge this because swap is freed. * This memcg can be obsolete one. We avoid calling css_tryget */ res_counter_uncharge(&memcg->memsw, PAGE_SIZE); mem_cgroup_put(memcg); } rcu_read_unlock(); } #endif /* * Before starting migration, account PAGE_SIZE to mem_cgroup that the old * page belongs to. */ int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr) { struct page_cgroup *pc; struct mem_cgroup *mem = NULL; int ret = 0; if (mem_cgroup_disabled()) return 0; pc = lookup_page_cgroup(page); lock_page_cgroup(pc); if (PageCgroupUsed(pc)) { mem = pc->mem_cgroup; css_get(&mem->css); } unlock_page_cgroup(pc); if (mem) { ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false); css_put(&mem->css); } *ptr = mem; return ret; } /* remove redundant charge if migration failed*/ void mem_cgroup_end_migration(struct mem_cgroup *mem, struct page *oldpage, struct page *newpage) { struct page *target, *unused; struct page_cgroup *pc; enum charge_type ctype; if (!mem) return; /* at migration success, oldpage->mapping is NULL. */ if (oldpage->mapping) { target = oldpage; unused = NULL; } else { target = newpage; unused = oldpage; } if (PageAnon(target)) ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; else if (page_is_file_cache(target)) ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; else ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; /* unused page is not on radix-tree now. */ if (unused) __mem_cgroup_uncharge_common(unused, ctype); pc = lookup_page_cgroup(target); /* * __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup. * So, double-counting is effectively avoided. */ __mem_cgroup_commit_charge(mem, pc, ctype); /* * Both of oldpage and newpage are still under lock_page(). * Then, we don't have to care about race in radix-tree. * But we have to be careful that this page is unmapped or not. * * There is a case for !page_mapped(). At the start of * migration, oldpage was mapped. But now, it's zapped. * But we know *target* page is not freed/reused under us. * mem_cgroup_uncharge_page() does all necessary checks. */ if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) mem_cgroup_uncharge_page(target); } /* * A call to try to shrink memory usage on charge failure at shmem's swapin. * Calling hierarchical_reclaim is not enough because we should update * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM. * Moreover considering hierarchy, we should reclaim from the mem_over_limit, * not from the memcg which this page would be charged to. * try_charge_swapin does all of these works properly. */ int mem_cgroup_shmem_charge_fallback(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { struct mem_cgroup *mem = NULL; int ret; if (mem_cgroup_disabled()) return 0; ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); if (!ret) mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */ return ret; } static DEFINE_MUTEX(set_limit_mutex); static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val) { int retry_count; int progress; u64 memswlimit; int ret = 0; int children = mem_cgroup_count_children(memcg); u64 curusage, oldusage; /* * For keeping hierarchical_reclaim simple, how long we should retry * is depends on callers. We set our retry-count to be function * of # of children which we should visit in this loop. */ retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); while (retry_count) { if (signal_pending(current)) { ret = -EINTR; break; } /* * Rather than hide all in some function, I do this in * open coded manner. You see what this really does. * We have to guarantee mem->res.limit < mem->memsw.limit. */ mutex_lock(&set_limit_mutex); memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); if (memswlimit < val) { ret = -EINVAL; mutex_unlock(&set_limit_mutex); break; } ret = res_counter_set_limit(&memcg->res, val); mutex_unlock(&set_limit_mutex); if (!ret) break; progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, false, true); curusage = res_counter_read_u64(&memcg->res, RES_USAGE); /* Usage is reduced ? */ if (curusage >= oldusage) retry_count--; else oldusage = curusage; } return ret; } int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, unsigned long long val) { int retry_count; u64 memlimit, oldusage, curusage; int children = mem_cgroup_count_children(memcg); int ret = -EBUSY; if (!do_swap_account) return -EINVAL; /* see mem_cgroup_resize_res_limit */ retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); while (retry_count) { if (signal_pending(current)) { ret = -EINTR; break; } /* * Rather than hide all in some function, I do this in * open coded manner. You see what this really does. * We have to guarantee mem->res.limit < mem->memsw.limit. */ mutex_lock(&set_limit_mutex); memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); if (memlimit > val) { ret = -EINVAL; mutex_unlock(&set_limit_mutex); break; } ret = res_counter_set_limit(&memcg->memsw, val); mutex_unlock(&set_limit_mutex); if (!ret) break; mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true, true); curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); /* Usage is reduced ? */ if (curusage >= oldusage) retry_count--; else oldusage = curusage; } return ret; } /* * This routine traverse page_cgroup in given list and drop them all. * *And* this routine doesn't reclaim page itself, just removes page_cgroup. */ static int mem_cgroup_force_empty_list(struct mem_cgroup *mem, int node, int zid, enum lru_list lru) { struct zone *zone; struct mem_cgroup_per_zone *mz; struct page_cgroup *pc, *busy; unsigned long flags, loop; struct list_head *list; int ret = 0; zone = &NODE_DATA(node)->node_zones[zid]; mz = mem_cgroup_zoneinfo(mem, node, zid); list = &mz->lists[lru]; loop = MEM_CGROUP_ZSTAT(mz, lru); /* give some margin against EBUSY etc...*/ loop += 256; busy = NULL; while (loop--) { ret = 0; spin_lock_irqsave(&zone->lru_lock, flags); if (list_empty(list)) { spin_unlock_irqrestore(&zone->lru_lock, flags); break; } pc = list_entry(list->prev, struct page_cgroup, lru); if (busy == pc) { list_move(&pc->lru, list); busy = 0; spin_unlock_irqrestore(&zone->lru_lock, flags); continue; } spin_unlock_irqrestore(&zone->lru_lock, flags); ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL); if (ret == -ENOMEM) break; if (ret == -EBUSY || ret == -EINVAL) { /* found lock contention or "pc" is obsolete. */ busy = pc; cond_resched(); } else busy = NULL; } if (!ret && !list_empty(list)) return -EBUSY; return ret; } /* * make mem_cgroup's charge to be 0 if there is no task. * This enables deleting this mem_cgroup. */ static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all) { int ret; int node, zid, shrink; int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; struct cgroup *cgrp = mem->css.cgroup; css_get(&mem->css); shrink = 0; /* should free all ? */ if (free_all) goto try_to_free; move_account: while (mem->res.usage > 0) { ret = -EBUSY; if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) goto out; ret = -EINTR; if (signal_pending(current)) goto out; /* This is for making all *used* pages to be on LRU. */ lru_add_drain_all(); ret = 0; for_each_node_state(node, N_HIGH_MEMORY) { for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) { enum lru_list l; for_each_lru(l) { ret = mem_cgroup_force_empty_list(mem, node, zid, l); if (ret) break; } } if (ret) break; } /* it seems parent cgroup doesn't have enough mem */ if (ret == -ENOMEM) goto try_to_free; cond_resched(); } ret = 0; out: css_put(&mem->css); return ret; try_to_free: /* returns EBUSY if there is a task or if we come here twice. */ if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) { ret = -EBUSY; goto out; } /* we call try-to-free pages for make this cgroup empty */ lru_add_drain_all(); /* try to free all pages in this cgroup */ shrink = 1; while (nr_retries && mem->res.usage > 0) { int progress; if (signal_pending(current)) { ret = -EINTR; goto out; } progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL, false, get_swappiness(mem)); if (!progress) { nr_retries--; /* maybe some writeback is necessary */ congestion_wait(WRITE, HZ/10); } } lru_add_drain(); /* try move_account...there may be some *locked* pages. */ if (mem->res.usage) goto move_account; ret = 0; goto out; } int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) { return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); } static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) { return mem_cgroup_from_cont(cont)->use_hierarchy; } static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, u64 val) { int retval = 0; struct mem_cgroup *mem = mem_cgroup_from_cont(cont); struct cgroup *parent = cont->parent; struct mem_cgroup *parent_mem = NULL; if (parent) parent_mem = mem_cgroup_from_cont(parent); cgroup_lock(); /* * If parent's use_hiearchy is set, we can't make any modifications * in the child subtrees. If it is unset, then the change can * occur, provided the current cgroup has no children. * * For the root cgroup, parent_mem is NULL, we allow value to be * set if there are no children. */ if ((!parent_mem || !parent_mem->use_hierarchy) && (val == 1 || val == 0)) { if (list_empty(&cont->children)) mem->use_hierarchy = val; else retval = -EBUSY; } else retval = -EINVAL; cgroup_unlock(); return retval; } static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) { struct mem_cgroup *mem = mem_cgroup_from_cont(cont); u64 val = 0; int type, name; type = MEMFILE_TYPE(cft->private); name = MEMFILE_ATTR(cft->private); switch (type) { case _MEM: val = res_counter_read_u64(&mem->res, name); break; case _MEMSWAP: if (do_swap_account) val = res_counter_read_u64(&mem->memsw, name); break; default: BUG(); break; } return val; } /* * The user of this function is... * RES_LIMIT. */ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, const char *buffer) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); int type, name; unsigned long long val; int ret; type = MEMFILE_TYPE(cft->private); name = MEMFILE_ATTR(cft->private); switch (name) { case RES_LIMIT: /* This function does all necessary parse...reuse it */ ret = res_counter_memparse_write_strategy(buffer, &val); if (ret) break; if (type == _MEM) ret = mem_cgroup_resize_limit(memcg, val); else ret = mem_cgroup_resize_memsw_limit(memcg, val); break; default: ret = -EINVAL; /* should be BUG() ? */ break; } return ret; } static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, unsigned long long *mem_limit, unsigned long long *memsw_limit) { struct cgroup *cgroup; unsigned long long min_limit, min_memsw_limit, tmp; min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); cgroup = memcg->css.cgroup; if (!memcg->use_hierarchy) goto out; while (cgroup->parent) { cgroup = cgroup->parent; memcg = mem_cgroup_from_cont(cgroup); if (!memcg->use_hierarchy) break; tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); min_limit = min(min_limit, tmp); tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); min_memsw_limit = min(min_memsw_limit, tmp); } out: *mem_limit = min_limit; *memsw_limit = min_memsw_limit; return; } static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) { struct mem_cgroup *mem; int type, name; mem = mem_cgroup_from_cont(cont); type = MEMFILE_TYPE(event); name = MEMFILE_ATTR(event); switch (name) { case RES_MAX_USAGE: if (type == _MEM) res_counter_reset_max(&mem->res); else res_counter_reset_max(&mem->memsw); break; case RES_FAILCNT: if (type == _MEM) res_counter_reset_failcnt(&mem->res); else res_counter_reset_failcnt(&mem->memsw); break; } return 0; } /* For read statistics */ enum { MCS_CACHE, MCS_RSS, MCS_PGPGIN, MCS_PGPGOUT, MCS_INACTIVE_ANON, MCS_ACTIVE_ANON, MCS_INACTIVE_FILE, MCS_ACTIVE_FILE, MCS_UNEVICTABLE, NR_MCS_STAT, }; struct mcs_total_stat { s64 stat[NR_MCS_STAT]; }; struct { char *local_name; char *total_name; } memcg_stat_strings[NR_MCS_STAT] = { {"cache", "total_cache"}, {"rss", "total_rss"}, {"pgpgin", "total_pgpgin"}, {"pgpgout", "total_pgpgout"}, {"inactive_anon", "total_inactive_anon"}, {"active_anon", "total_active_anon"}, {"inactive_file", "total_inactive_file"}, {"active_file", "total_active_file"}, {"unevictable", "total_unevictable"} }; static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data) { struct mcs_total_stat *s = data; s64 val; /* per cpu stat */ val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_CACHE); s->stat[MCS_CACHE] += val * PAGE_SIZE; val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS); s->stat[MCS_RSS] += val * PAGE_SIZE; val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGIN_COUNT); s->stat[MCS_PGPGIN] += val; val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGOUT_COUNT); s->stat[MCS_PGPGOUT] += val; /* per zone stat */ val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON); s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE; val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON); s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE; val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE); s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE; val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE); s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE; val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE); s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE; return 0; } static void mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) { mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat); } static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, struct cgroup_map_cb *cb) { struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); struct mcs_total_stat mystat; int i; memset(&mystat, 0, sizeof(mystat)); mem_cgroup_get_local_stat(mem_cont, &mystat); for (i = 0; i < NR_MCS_STAT; i++) cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]); /* Hierarchical information */ { unsigned long long limit, memsw_limit; memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit); cb->fill(cb, "hierarchical_memory_limit", limit); if (do_swap_account) cb->fill(cb, "hierarchical_memsw_limit", memsw_limit); } memset(&mystat, 0, sizeof(mystat)); mem_cgroup_get_total_stat(mem_cont, &mystat); for (i = 0; i < NR_MCS_STAT; i++) cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]); #ifdef CONFIG_DEBUG_VM cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL)); { int nid, zid; struct mem_cgroup_per_zone *mz; unsigned long recent_rotated[2] = {0, 0}; unsigned long recent_scanned[2] = {0, 0}; for_each_online_node(nid) for (zid = 0; zid < MAX_NR_ZONES; zid++) { mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); recent_rotated[0] += mz->reclaim_stat.recent_rotated[0]; recent_rotated[1] += mz->reclaim_stat.recent_rotated[1]; recent_scanned[0] += mz->reclaim_stat.recent_scanned[0]; recent_scanned[1] += mz->reclaim_stat.recent_scanned[1]; } cb->fill(cb, "recent_rotated_anon", recent_rotated[0]); cb->fill(cb, "recent_rotated_file", recent_rotated[1]); cb->fill(cb, "recent_scanned_anon", recent_scanned[0]); cb->fill(cb, "recent_scanned_file", recent_scanned[1]); } #endif return 0; } static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); return get_swappiness(memcg); } static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, u64 val) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); struct mem_cgroup *parent; if (val > 100) return -EINVAL; if (cgrp->parent == NULL) return -EINVAL; parent = mem_cgroup_from_cont(cgrp->parent); cgroup_lock(); /* If under hierarchy, only empty-root can set this value */ if ((parent->use_hierarchy) || (memcg->use_hierarchy && !list_empty(&cgrp->children))) { cgroup_unlock(); return -EINVAL; } spin_lock(&memcg->reclaim_param_lock); memcg->swappiness = val; spin_unlock(&memcg->reclaim_param_lock); cgroup_unlock(); return 0; } static struct cftype mem_cgroup_files[] = { { .name = "usage_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), .read_u64 = mem_cgroup_read, }, { .name = "max_usage_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, { .name = "limit_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), .write_string = mem_cgroup_write, .read_u64 = mem_cgroup_read, }, { .name = "failcnt", .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, { .name = "stat", .read_map = mem_control_stat_show, }, { .name = "force_empty", .trigger = mem_cgroup_force_empty_write, }, { .name = "use_hierarchy", .write_u64 = mem_cgroup_hierarchy_write, .read_u64 = mem_cgroup_hierarchy_read, }, { .name = "swappiness", .read_u64 = mem_cgroup_swappiness_read, .write_u64 = mem_cgroup_swappiness_write, }, }; #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP static struct cftype memsw_cgroup_files[] = { { .name = "memsw.usage_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), .read_u64 = mem_cgroup_read, }, { .name = "memsw.max_usage_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, { .name = "memsw.limit_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), .write_string = mem_cgroup_write, .read_u64 = mem_cgroup_read, }, { .name = "memsw.failcnt", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, }; static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) { if (!do_swap_account) return 0; return cgroup_add_files(cont, ss, memsw_cgroup_files, ARRAY_SIZE(memsw_cgroup_files)); }; #else static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) { return 0; } #endif static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) { struct mem_cgroup_per_node *pn; struct mem_cgroup_per_zone *mz; enum lru_list l; int zone, tmp = node; /* * This routine is called against possible nodes. * But it's BUG to call kmalloc() against offline node. * * TODO: this routine can waste much memory for nodes which will * never be onlined. It's better to use memory hotplug callback * function. */ if (!node_state(node, N_NORMAL_MEMORY)) tmp = -1; pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp); if (!pn) return 1; mem->info.nodeinfo[node] = pn; memset(pn, 0, sizeof(*pn)); for (zone = 0; zone < MAX_NR_ZONES; zone++) { mz = &pn->zoneinfo[zone]; for_each_lru(l) INIT_LIST_HEAD(&mz->lists[l]); } return 0; } static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) { kfree(mem->info.nodeinfo[node]); } static int mem_cgroup_size(void) { int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu); return sizeof(struct mem_cgroup) + cpustat_size; } static struct mem_cgroup *mem_cgroup_alloc(void) { struct mem_cgroup *mem; int size = mem_cgroup_size(); if (size < PAGE_SIZE) mem = kmalloc(size, GFP_KERNEL); else mem = vmalloc(size); if (mem) memset(mem, 0, size); return mem; } /* * At destroying mem_cgroup, references from swap_cgroup can remain. * (scanning all at force_empty is too costly...) * * Instead of clearing all references at force_empty, we remember * the number of reference from swap_cgroup and free mem_cgroup when * it goes down to 0. * * Removal of cgroup itself succeeds regardless of refs from swap. */ static void __mem_cgroup_free(struct mem_cgroup *mem) { int node; free_css_id(&mem_cgroup_subsys, &mem->css); for_each_node_state(node, N_POSSIBLE) free_mem_cgroup_per_zone_info(mem, node); if (mem_cgroup_size() < PAGE_SIZE) kfree(mem); else vfree(mem); } static void mem_cgroup_get(struct mem_cgroup *mem) { atomic_inc(&mem->refcnt); } static void mem_cgroup_put(struct mem_cgroup *mem) { if (atomic_dec_and_test(&mem->refcnt)) { struct mem_cgroup *parent = parent_mem_cgroup(mem); __mem_cgroup_free(mem); if (parent) mem_cgroup_put(parent); } } /* * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. */ static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) { if (!mem->res.parent) return NULL; return mem_cgroup_from_res_counter(mem->res.parent, res); } #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP static void __init enable_swap_cgroup(void) { if (!mem_cgroup_disabled() && really_do_swap_account) do_swap_account = 1; } #else static void __init enable_swap_cgroup(void) { } #endif static struct cgroup_subsys_state * __ref mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) { struct mem_cgroup *mem, *parent; long error = -ENOMEM; int node; mem = mem_cgroup_alloc(); if (!mem) return ERR_PTR(error); for_each_node_state(node, N_POSSIBLE) if (alloc_mem_cgroup_per_zone_info(mem, node)) goto free_out; /* root ? */ if (cont->parent == NULL) { enable_swap_cgroup(); parent = NULL; } else { parent = mem_cgroup_from_cont(cont->parent); mem->use_hierarchy = parent->use_hierarchy; } if (parent && parent->use_hierarchy) { res_counter_init(&mem->res, &parent->res); res_counter_init(&mem->memsw, &parent->memsw); /* * We increment refcnt of the parent to ensure that we can * safely access it on res_counter_charge/uncharge. * This refcnt will be decremented when freeing this * mem_cgroup(see mem_cgroup_put). */ mem_cgroup_get(parent); } else { res_counter_init(&mem->res, NULL); res_counter_init(&mem->memsw, NULL); } mem->last_scanned_child = 0; spin_lock_init(&mem->reclaim_param_lock); if (parent) mem->swappiness = get_swappiness(parent); atomic_set(&mem->refcnt, 1); return &mem->css; free_out: __mem_cgroup_free(mem); return ERR_PTR(error); } static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss, struct cgroup *cont) { struct mem_cgroup *mem = mem_cgroup_from_cont(cont); return mem_cgroup_force_empty(mem, false); } static void mem_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cont) { struct mem_cgroup *mem = mem_cgroup_from_cont(cont); mem_cgroup_put(mem); } static int mem_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) { int ret; ret = cgroup_add_files(cont, ss, mem_cgroup_files, ARRAY_SIZE(mem_cgroup_files)); if (!ret) ret = register_memsw_files(cont, ss); return ret; } static void mem_cgroup_move_task(struct cgroup_subsys *ss, struct cgroup *cont, struct cgroup *old_cont, struct task_struct *p) { mutex_lock(&memcg_tasklist); /* * FIXME: It's better to move charges of this process from old * memcg to new memcg. But it's just on TODO-List now. */ mutex_unlock(&memcg_tasklist); } struct cgroup_subsys mem_cgroup_subsys = { .name = "memory", .subsys_id = mem_cgroup_subsys_id, .create = mem_cgroup_create, .pre_destroy = mem_cgroup_pre_destroy, .destroy = mem_cgroup_destroy, .populate = mem_cgroup_populate, .attach = mem_cgroup_move_task, .early_init = 0, .use_id = 1, }; #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP static int __init disable_swap_account(char *s) { really_do_swap_account = 0; return 1; } __setup("noswapaccount", disable_swap_account); #endif