/* 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/smp.h> #include <linux/page-flags.h> #include <linux/backing-dev.h> #include <linux/bit_spinlock.h> #include <linux/rcupdate.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 <asm/uaccess.h> struct cgroup_subsys mem_cgroup_subsys __read_mostly; static struct kmem_cache *page_cgroup_cache __read_mostly; #define MEM_CGROUP_RECLAIM_RETRIES 5 /* * 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[NR_CPUS]; }; /* * For accounting under irq disable, no need for increment preempt count. */ static void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat *stat, enum mem_cgroup_stat_index idx, int val) { int cpu = smp_processor_id(); stat->cpustat[cpu].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; } /* * per-zone information in memory controller. */ enum mem_cgroup_zstat_index { MEM_CGROUP_ZSTAT_ACTIVE, MEM_CGROUP_ZSTAT_INACTIVE, NR_MEM_CGROUP_ZSTAT, }; struct mem_cgroup_per_zone { /* * spin_lock to protect the per cgroup LRU */ spinlock_t lru_lock; struct list_head active_list; struct list_head inactive_list; unsigned long count[NR_MEM_CGROUP_ZSTAT]; }; /* 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; /* * Per cgroup active and inactive list, similar to the * per zone LRU lists. */ struct mem_cgroup_lru_info info; int prev_priority; /* for recording reclaim priority */ /* * statistics. */ struct mem_cgroup_stat stat; }; static struct mem_cgroup init_mem_cgroup; /* * We use the lower bit of the page->page_cgroup pointer as a bit spin * lock. We need to ensure that page->page_cgroup is at least two * byte aligned (based on comments from Nick Piggin). But since * bit_spin_lock doesn't actually set that lock bit in a non-debug * uniprocessor kernel, we should avoid setting it here too. */ #define PAGE_CGROUP_LOCK_BIT 0x0 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) #define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT) #else #define PAGE_CGROUP_LOCK 0x0 #endif /* * A page_cgroup page is associated with every page descriptor. The * page_cgroup helps us identify information about the cgroup */ struct page_cgroup { struct list_head lru; /* per cgroup LRU list */ struct page *page; struct mem_cgroup *mem_cgroup; int flags; }; #define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */ #define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */ static int page_cgroup_nid(struct page_cgroup *pc) { return page_to_nid(pc->page); } static enum zone_type page_cgroup_zid(struct page_cgroup *pc) { return page_zonenum(pc->page); } enum charge_type { MEM_CGROUP_CHARGE_TYPE_CACHE = 0, MEM_CGROUP_CHARGE_TYPE_MAPPED, MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ }; /* * Always modified under lru lock. Then, not necessary to preempt_disable() */ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags, bool charge) { int val = (charge)? 1 : -1; struct mem_cgroup_stat *stat = &mem->stat; VM_BUG_ON(!irqs_disabled()); if (flags & PAGE_CGROUP_FLAG_CACHE) __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_CACHE, val); else __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_RSS, val); if (charge) __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_PGPGIN_COUNT, 1); else __mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_PGPGOUT_COUNT, 1); } 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); return mem_cgroup_zoneinfo(mem, nid, zid); } static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem, enum mem_cgroup_zstat_index 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) { return container_of(task_subsys_state(p, mem_cgroup_subsys_id), struct mem_cgroup, css); } static inline int page_cgroup_locked(struct page *page) { return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); } static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc) { VM_BUG_ON(!page_cgroup_locked(page)); page->page_cgroup = ((unsigned long)pc | PAGE_CGROUP_LOCK); } struct page_cgroup *page_get_page_cgroup(struct page *page) { return (struct page_cgroup *) (page->page_cgroup & ~PAGE_CGROUP_LOCK); } static void lock_page_cgroup(struct page *page) { bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); } static int try_lock_page_cgroup(struct page *page) { return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); } static void unlock_page_cgroup(struct page *page) { bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); } static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz, struct page_cgroup *pc) { int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; if (from) MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1; else MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1; mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false); list_del(&pc->lru); } static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz, struct page_cgroup *pc) { int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; if (!to) { MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1; list_add(&pc->lru, &mz->inactive_list); } else { MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1; list_add(&pc->lru, &mz->active_list); } mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true); } static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active) { int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc); if (from) MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1; else MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1; if (active) { MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1; pc->flags |= PAGE_CGROUP_FLAG_ACTIVE; list_move(&pc->lru, &mz->active_list); } else { MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1; pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE; list_move(&pc->lru, &mz->inactive_list); } } int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) { int ret; task_lock(task); ret = task->mm && mm_match_cgroup(task->mm, mem); task_unlock(task); return ret; } /* * This routine assumes that the appropriate zone's lru lock is already held */ void mem_cgroup_move_lists(struct page *page, bool active) { struct page_cgroup *pc; struct mem_cgroup_per_zone *mz; unsigned long flags; if (mem_cgroup_subsys.disabled) return; /* * We cannot lock_page_cgroup while holding zone's lru_lock, * because other holders of lock_page_cgroup can be interrupted * with an attempt to rotate_reclaimable_page. But we cannot * safely get to page_cgroup without it, so just try_lock it: * mem_cgroup_isolate_pages allows for page left on wrong list. */ if (!try_lock_page_cgroup(page)) return; pc = page_get_page_cgroup(page); if (pc) { mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); __mem_cgroup_move_lists(pc, active); spin_unlock_irqrestore(&mz->lru_lock, flags); } unlock_page_cgroup(page); } /* * Calculate mapped_ratio under memory controller. This will be used in * vmscan.c for deteremining we have to reclaim mapped pages. */ int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem) { long total, rss; /* * usage is recorded in bytes. But, here, we assume the number of * physical pages can be represented by "long" on any arch. */ total = (long) (mem->res.usage >> PAGE_SHIFT) + 1L; rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS); return (int)((rss * 100L) / total); } /* * This function is called from vmscan.c. In page reclaiming loop. balance * between active and inactive list is calculated. For memory controller * page reclaiming, we should use using mem_cgroup's imbalance rather than * zone's global lru imbalance. */ long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem) { unsigned long active, inactive; /* active and inactive are the number of pages. 'long' is ok.*/ active = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_ACTIVE); inactive = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_INACTIVE); return (long) (active / (inactive + 1)); } /* * prev_priority control...this will be used in memory reclaim path. */ int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem) { return mem->prev_priority; } void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority) { if (priority < mem->prev_priority) mem->prev_priority = priority; } void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority) { mem->prev_priority = priority; } /* * Calculate # of pages to be scanned in this priority/zone. * See also vmscan.c * * priority starts from "DEF_PRIORITY" and decremented in each loop. * (see include/linux/mmzone.h) */ long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem, struct zone *zone, int priority) { long nr_active; int nid = zone->zone_pgdat->node_id; int zid = zone_idx(zone); struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid); nr_active = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE); return (nr_active >> priority); } long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem, struct zone *zone, int priority) { long nr_inactive; int nid = zone->zone_pgdat->node_id; int zid = zone_idx(zone); struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid); nr_inactive = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE); return (nr_inactive >> priority); } 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) { 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; BUG_ON(!mem_cont); mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); if (active) src = &mz->active_list; else src = &mz->inactive_list; spin_lock(&mz->lru_lock); scan = 0; list_for_each_entry_safe_reverse(pc, tmp, src, lru) { if (scan >= nr_to_scan) break; page = pc->page; if (unlikely(!PageLRU(page))) continue; if (PageActive(page) && !active) { __mem_cgroup_move_lists(pc, true); continue; } if (!PageActive(page) && active) { __mem_cgroup_move_lists(pc, false); continue; } scan++; list_move(&pc->lru, &pc_list); if (__isolate_lru_page(page, mode) == 0) { list_move(&page->lru, dst); nr_taken++; } } list_splice(&pc_list, src); spin_unlock(&mz->lru_lock); *scanned = scan; return nr_taken; } /* * 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; unsigned long flags; unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES; struct mem_cgroup_per_zone *mz; pc = kmem_cache_alloc(page_cgroup_cache, gfp_mask); if (unlikely(pc == NULL)) goto err; /* * 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). */ if (likely(!memcg)) { rcu_read_lock(); mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); /* * For every charge from the cgroup, increment reference count */ css_get(&mem->css); rcu_read_unlock(); } else { mem = memcg; css_get(&memcg->css); } while (res_counter_charge(&mem->res, PAGE_SIZE)) { if (!(gfp_mask & __GFP_WAIT)) goto out; if (try_to_free_mem_cgroup_pages(mem, gfp_mask)) 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 (res_counter_check_under_limit(&mem->res)) continue; if (!nr_retries--) { mem_cgroup_out_of_memory(mem, gfp_mask); goto out; } } pc->mem_cgroup = mem; pc->page = page; /* * If a page is accounted as a page cache, insert to inactive list. * If anon, insert to active list. */ if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE) pc->flags = PAGE_CGROUP_FLAG_CACHE; else pc->flags = PAGE_CGROUP_FLAG_ACTIVE; lock_page_cgroup(page); if (unlikely(page_get_page_cgroup(page))) { unlock_page_cgroup(page); res_counter_uncharge(&mem->res, PAGE_SIZE); css_put(&mem->css); kmem_cache_free(page_cgroup_cache, pc); goto done; } page_assign_page_cgroup(page, pc); mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); __mem_cgroup_add_list(mz, pc); spin_unlock_irqrestore(&mz->lru_lock, flags); unlock_page_cgroup(page); done: return 0; out: css_put(&mem->css); kmem_cache_free(page_cgroup_cache, pc); err: return -ENOMEM; } int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { if (mem_cgroup_subsys.disabled) 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); } int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { if (mem_cgroup_subsys.disabled) 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.) */ if (!(gfp_mask & __GFP_WAIT)) { struct page_cgroup *pc; lock_page_cgroup(page); pc = page_get_page_cgroup(page); if (pc) { VM_BUG_ON(pc->page != page); VM_BUG_ON(!pc->mem_cgroup); unlock_page_cgroup(page); return 0; } unlock_page_cgroup(page); } if (unlikely(!mm)) mm = &init_mm; return mem_cgroup_charge_common(page, mm, gfp_mask, MEM_CGROUP_CHARGE_TYPE_CACHE, NULL); } /* * uncharge if !page_mapped(page) */ static void __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) { struct page_cgroup *pc; struct mem_cgroup *mem; struct mem_cgroup_per_zone *mz; unsigned long flags; if (mem_cgroup_subsys.disabled) return; /* * Check if our page_cgroup is valid */ lock_page_cgroup(page); pc = page_get_page_cgroup(page); if (unlikely(!pc)) goto unlock; VM_BUG_ON(pc->page != page); if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) && ((pc->flags & PAGE_CGROUP_FLAG_CACHE) || page_mapped(page))) goto unlock; mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); __mem_cgroup_remove_list(mz, pc); spin_unlock_irqrestore(&mz->lru_lock, flags); page_assign_page_cgroup(page, NULL); unlock_page_cgroup(page); mem = pc->mem_cgroup; res_counter_uncharge(&mem->res, PAGE_SIZE); css_put(&mem->css); kmem_cache_free(page_cgroup_cache, pc); return; unlock: unlock_page_cgroup(page); } void mem_cgroup_uncharge_page(struct page *page) { __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)); __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); } /* * Before starting migration, account against new page. */ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage) { struct page_cgroup *pc; struct mem_cgroup *mem = NULL; enum charge_type ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; int ret = 0; if (mem_cgroup_subsys.disabled) return 0; lock_page_cgroup(page); pc = page_get_page_cgroup(page); if (pc) { mem = pc->mem_cgroup; css_get(&mem->css); if (pc->flags & PAGE_CGROUP_FLAG_CACHE) ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; } unlock_page_cgroup(page); if (mem) { ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL, ctype, mem); css_put(&mem->css); } return ret; } /* remove redundant charge if migration failed*/ void mem_cgroup_end_migration(struct page *newpage) { /* * At success, page->mapping is not NULL. * special rollback care is necessary when * 1. at migration failure. (newpage->mapping is cleared in this case) * 2. the newpage was moved but not remapped again because the task * exits and the newpage is obsolete. In this case, the new page * may be a swapcache. So, we just call mem_cgroup_uncharge_page() * always for avoiding mess. The page_cgroup will be removed if * unnecessary. File cache pages is still on radix-tree. Don't * care it. */ if (!newpage->mapping) __mem_cgroup_uncharge_common(newpage, MEM_CGROUP_CHARGE_TYPE_FORCE); else if (PageAnon(newpage)) mem_cgroup_uncharge_page(newpage); } /* * A call to try to shrink memory usage under specified resource controller. * This is typically used for page reclaiming for shmem for reducing side * effect of page allocation from shmem, which is used by some mem_cgroup. */ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask) { struct mem_cgroup *mem; int progress = 0; int retry = MEM_CGROUP_RECLAIM_RETRIES; if (mem_cgroup_subsys.disabled) return 0; rcu_read_lock(); mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); css_get(&mem->css); rcu_read_unlock(); do { progress = try_to_free_mem_cgroup_pages(mem, gfp_mask); } while (!progress && --retry); css_put(&mem->css); if (!retry) return -ENOMEM; return 0; } int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val) { int retry_count = MEM_CGROUP_RECLAIM_RETRIES; int progress; int ret = 0; while (res_counter_set_limit(&memcg->res, val)) { if (signal_pending(current)) { ret = -EINTR; break; } if (!retry_count) { ret = -EBUSY; break; } progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL); if (!progress) retry_count--; } 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. */ #define FORCE_UNCHARGE_BATCH (128) static void mem_cgroup_force_empty_list(struct mem_cgroup *mem, struct mem_cgroup_per_zone *mz, int active) { struct page_cgroup *pc; struct page *page; int count = FORCE_UNCHARGE_BATCH; unsigned long flags; struct list_head *list; if (active) list = &mz->active_list; else list = &mz->inactive_list; spin_lock_irqsave(&mz->lru_lock, flags); while (!list_empty(list)) { pc = list_entry(list->prev, struct page_cgroup, lru); page = pc->page; get_page(page); spin_unlock_irqrestore(&mz->lru_lock, flags); /* * Check if this page is on LRU. !LRU page can be found * if it's under page migration. */ if (PageLRU(page)) { __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_FORCE); put_page(page); if (--count <= 0) { count = FORCE_UNCHARGE_BATCH; cond_resched(); } } else cond_resched(); spin_lock_irqsave(&mz->lru_lock, flags); } spin_unlock_irqrestore(&mz->lru_lock, flags); } /* * 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) { int ret = -EBUSY; int node, zid; css_get(&mem->css); /* * page reclaim code (kswapd etc..) will move pages between * active_list <-> inactive_list while we don't take a lock. * So, we have to do loop here until all lists are empty. */ while (mem->res.usage > 0) { if (atomic_read(&mem->css.cgroup->count) > 0) goto out; for_each_node_state(node, N_POSSIBLE) for (zid = 0; zid < MAX_NR_ZONES; zid++) { struct mem_cgroup_per_zone *mz; mz = mem_cgroup_zoneinfo(mem, node, zid); /* drop all page_cgroup in active_list */ mem_cgroup_force_empty_list(mem, mz, 1); /* drop all page_cgroup in inactive_list */ mem_cgroup_force_empty_list(mem, mz, 0); } } ret = 0; out: css_put(&mem->css); return ret; } static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) { return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res, cft->private); } /* * 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); unsigned long long val; int ret; switch (cft->private) { case RES_LIMIT: /* This function does all necessary parse...reuse it */ ret = res_counter_memparse_write_strategy(buffer, &val); if (!ret) ret = mem_cgroup_resize_limit(memcg, val); break; default: ret = -EINVAL; /* should be BUG() ? */ break; } return ret; } static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) { struct mem_cgroup *mem; mem = mem_cgroup_from_cont(cont); switch (event) { case RES_MAX_USAGE: res_counter_reset_max(&mem->res); break; case RES_FAILCNT: res_counter_reset_failcnt(&mem->res); break; } return 0; } static int mem_force_empty_write(struct cgroup *cont, unsigned int event) { return mem_cgroup_force_empty(mem_cgroup_from_cont(cont)); } static const struct mem_cgroup_stat_desc { const char *msg; u64 unit; } mem_cgroup_stat_desc[] = { [MEM_CGROUP_STAT_CACHE] = { "cache", PAGE_SIZE, }, [MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, }, [MEM_CGROUP_STAT_PGPGIN_COUNT] = {"pgpgin", 1, }, [MEM_CGROUP_STAT_PGPGOUT_COUNT] = {"pgpgout", 1, }, }; 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 mem_cgroup_stat *stat = &mem_cont->stat; int i; for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) { s64 val; val = mem_cgroup_read_stat(stat, i); val *= mem_cgroup_stat_desc[i].unit; cb->fill(cb, mem_cgroup_stat_desc[i].msg, val); } /* showing # of active pages */ { unsigned long active, inactive; inactive = mem_cgroup_get_all_zonestat(mem_cont, MEM_CGROUP_ZSTAT_INACTIVE); active = mem_cgroup_get_all_zonestat(mem_cont, MEM_CGROUP_ZSTAT_ACTIVE); cb->fill(cb, "active", (active) * PAGE_SIZE); cb->fill(cb, "inactive", (inactive) * PAGE_SIZE); } return 0; } static struct cftype mem_cgroup_files[] = { { .name = "usage_in_bytes", .private = RES_USAGE, .read_u64 = mem_cgroup_read, }, { .name = "max_usage_in_bytes", .private = RES_MAX_USAGE, .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, { .name = "limit_in_bytes", .private = RES_LIMIT, .write_string = mem_cgroup_write, .read_u64 = mem_cgroup_read, }, { .name = "failcnt", .private = RES_FAILCNT, .trigger = mem_cgroup_reset, .read_u64 = mem_cgroup_read, }, { .name = "force_empty", .trigger = mem_force_empty_write, }, { .name = "stat", .read_map = mem_control_stat_show, }, }; 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; 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]; INIT_LIST_HEAD(&mz->active_list); INIT_LIST_HEAD(&mz->inactive_list); spin_lock_init(&mz->lru_lock); } return 0; } static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) { kfree(mem->info.nodeinfo[node]); } static struct mem_cgroup *mem_cgroup_alloc(void) { struct mem_cgroup *mem; if (sizeof(*mem) < PAGE_SIZE) mem = kmalloc(sizeof(*mem), GFP_KERNEL); else mem = vmalloc(sizeof(*mem)); if (mem) memset(mem, 0, sizeof(*mem)); return mem; } static void mem_cgroup_free(struct mem_cgroup *mem) { if (sizeof(*mem) < PAGE_SIZE) kfree(mem); else vfree(mem); } static struct cgroup_subsys_state * mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) { struct mem_cgroup *mem; int node; if (unlikely((cont->parent) == NULL)) { mem = &init_mem_cgroup; page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC); } else { mem = mem_cgroup_alloc(); if (!mem) return ERR_PTR(-ENOMEM); } res_counter_init(&mem->res); for_each_node_state(node, N_POSSIBLE) if (alloc_mem_cgroup_per_zone_info(mem, node)) goto free_out; return &mem->css; free_out: for_each_node_state(node, N_POSSIBLE) free_mem_cgroup_per_zone_info(mem, node); if (cont->parent != NULL) mem_cgroup_free(mem); return ERR_PTR(-ENOMEM); } static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss, struct cgroup *cont) { struct mem_cgroup *mem = mem_cgroup_from_cont(cont); mem_cgroup_force_empty(mem); } static void mem_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cont) { int node; struct mem_cgroup *mem = mem_cgroup_from_cont(cont); for_each_node_state(node, N_POSSIBLE) free_mem_cgroup_per_zone_info(mem, node); mem_cgroup_free(mem_cgroup_from_cont(cont)); } static int mem_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) { return cgroup_add_files(cont, ss, mem_cgroup_files, ARRAY_SIZE(mem_cgroup_files)); } static void mem_cgroup_move_task(struct cgroup_subsys *ss, struct cgroup *cont, struct cgroup *old_cont, struct task_struct *p) { struct mm_struct *mm; struct mem_cgroup *mem, *old_mem; mm = get_task_mm(p); if (mm == NULL) return; mem = mem_cgroup_from_cont(cont); old_mem = mem_cgroup_from_cont(old_cont); if (mem == old_mem) goto out; /* * Only thread group leaders are allowed to migrate, the mm_struct is * in effect owned by the leader */ if (!thread_group_leader(p)) goto out; out: mmput(mm); } 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, };