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Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 1192 |
1 files changed, 1192 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c new file mode 100644 index 00000000000..5c2c702af61 --- /dev/null +++ b/mm/memcontrol.c @@ -0,0 +1,1192 @@ +/* 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/swap.h> +#include <linux/spinlock.h> +#include <linux/fs.h> +#include <linux/seq_file.h> + +#include <asm/uaccess.h> + +struct cgroup_subsys mem_cgroup_subsys; +static const int 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_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; +}; + +/* + * 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 atleast two + * byte aligned (based on comments from Nick Piggin) + */ +#define PAGE_CGROUP_LOCK_BIT 0x0 +#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT) + +/* + * 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; + atomic_t ref_cnt; /* Helpful when pages move b/w */ + /* mapped and cached states */ + int flags; +}; +#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */ +#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */ + +static inline int page_cgroup_nid(struct page_cgroup *pc) +{ + return page_to_nid(pc->page); +} + +static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc) +{ + return page_zonenum(pc->page); +} + +enum { + MEM_CGROUP_TYPE_UNSPEC = 0, + MEM_CGROUP_TYPE_MAPPED, + MEM_CGROUP_TYPE_CACHED, + MEM_CGROUP_TYPE_ALL, + MEM_CGROUP_TYPE_MAX, +}; + +enum charge_type { + MEM_CGROUP_CHARGE_TYPE_CACHE = 0, + MEM_CGROUP_CHARGE_TYPE_MAPPED, +}; + + +/* + * 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); +} + +static inline struct mem_cgroup_per_zone * +mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid) +{ + BUG_ON(!mem->info.nodeinfo[nid]); + return &mem->info.nodeinfo[nid]->zoneinfo[zid]; +} + +static inline 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 init_mem_cgroup; + +static inline +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); +} + +static inline +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); +} + +void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p) +{ + struct mem_cgroup *mem; + + mem = mem_cgroup_from_task(p); + css_get(&mem->css); + mm->mem_cgroup = mem; +} + +void mm_free_cgroup(struct mm_struct *mm) +{ + css_put(&mm->mem_cgroup->css); +} + +static inline int page_cgroup_locked(struct page *page) +{ + return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, + &page->page_cgroup); +} + +void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc) +{ + int locked; + + /* + * While resetting the page_cgroup we might not hold the + * page_cgroup lock. free_hot_cold_page() is an example + * of such a scenario + */ + if (pc) + VM_BUG_ON(!page_cgroup_locked(page)); + locked = (page->page_cgroup & PAGE_CGROUP_LOCK); + page->page_cgroup = ((unsigned long)pc | locked); +} + +struct page_cgroup *page_get_page_cgroup(struct page *page) +{ + return (struct page_cgroup *) + (page->page_cgroup & ~PAGE_CGROUP_LOCK); +} + +static void __always_inline lock_page_cgroup(struct page *page) +{ + bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); + VM_BUG_ON(!page_cgroup_locked(page)); +} + +static void __always_inline unlock_page_cgroup(struct page *page) +{ + bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); +} + +/* + * Tie new page_cgroup to struct page under lock_page_cgroup() + * This can fail if the page has been tied to a page_cgroup. + * If success, returns 0. + */ +static int page_cgroup_assign_new_page_cgroup(struct page *page, + struct page_cgroup *pc) +{ + int ret = 0; + + lock_page_cgroup(page); + if (!page_get_page_cgroup(page)) + page_assign_page_cgroup(page, pc); + else /* A page is tied to other pc. */ + ret = 1; + unlock_page_cgroup(page); + return ret; +} + +/* + * Clear page->page_cgroup member under lock_page_cgroup(). + * If given "pc" value is different from one page->page_cgroup, + * page->cgroup is not cleared. + * Returns a value of page->page_cgroup at lock taken. + * A can can detect failure of clearing by following + * clear_page_cgroup(page, pc) == pc + */ + +static struct page_cgroup *clear_page_cgroup(struct page *page, + struct page_cgroup *pc) +{ + struct page_cgroup *ret; + /* lock and clear */ + lock_page_cgroup(page); + ret = page_get_page_cgroup(page); + if (likely(ret == pc)) + page_assign_page_cgroup(page, NULL); + unlock_page_cgroup(page); + return ret; +} + +static void __mem_cgroup_remove_list(struct page_cgroup *pc) +{ + 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; + + mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false); + list_del_init(&pc->lru); +} + +static void __mem_cgroup_add_list(struct page_cgroup *pc) +{ + int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; + struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc); + + 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_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_cgroup *pc, bool active) +{ + struct mem_cgroup_per_zone *mz; + unsigned long flags; + + if (!pc) + return; + + 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); +} + +/* + * 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; + + 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; + VM_BUG_ON(!pc); + + 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 *mem; + struct page_cgroup *pc; + unsigned long flags; + unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + struct mem_cgroup_per_zone *mz; + + /* + * Should page_cgroup's go to their own slab? + * One could optimize the performance of the charging routine + * by saving a bit in the page_flags and using it as a lock + * to see if the cgroup page already has a page_cgroup associated + * with it + */ +retry: + if (page) { + lock_page_cgroup(page); + pc = page_get_page_cgroup(page); + /* + * The page_cgroup exists and + * the page has already been accounted. + */ + if (pc) { + if (unlikely(!atomic_inc_not_zero(&pc->ref_cnt))) { + /* this page is under being uncharged ? */ + unlock_page_cgroup(page); + cpu_relax(); + goto retry; + } else { + unlock_page_cgroup(page); + goto done; + } + } + unlock_page_cgroup(page); + } + + pc = kzalloc(sizeof(struct page_cgroup), gfp_mask); + if (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 (!mm) + mm = &init_mm; + + rcu_read_lock(); + mem = rcu_dereference(mm->mem_cgroup); + /* + * For every charge from the cgroup, increment reference + * count + */ + css_get(&mem->css); + rcu_read_unlock(); + + /* + * If we created the page_cgroup, we should free it on exceeding + * the cgroup limit. + */ + 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; + } + congestion_wait(WRITE, HZ/10); + } + + atomic_set(&pc->ref_cnt, 1); + pc->mem_cgroup = mem; + pc->page = page; + pc->flags = PAGE_CGROUP_FLAG_ACTIVE; + if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE) + pc->flags |= PAGE_CGROUP_FLAG_CACHE; + + if (!page || page_cgroup_assign_new_page_cgroup(page, pc)) { + /* + * Another charge has been added to this page already. + * We take lock_page_cgroup(page) again and read + * page->cgroup, increment refcnt.... just retry is OK. + */ + res_counter_uncharge(&mem->res, PAGE_SIZE); + css_put(&mem->css); + kfree(pc); + if (!page) + goto done; + goto retry; + } + + mz = page_cgroup_zoneinfo(pc); + spin_lock_irqsave(&mz->lru_lock, flags); + /* Update statistics vector */ + __mem_cgroup_add_list(pc); + spin_unlock_irqrestore(&mz->lru_lock, flags); + +done: + return 0; +out: + css_put(&mem->css); + kfree(pc); +err: + return -ENOMEM; +} + +int mem_cgroup_charge(struct page *page, struct mm_struct *mm, + gfp_t gfp_mask) +{ + return mem_cgroup_charge_common(page, mm, gfp_mask, + MEM_CGROUP_CHARGE_TYPE_MAPPED); +} + +/* + * See if the cached pages should be charged at all? + */ +int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, + gfp_t gfp_mask) +{ + int ret = 0; + if (!mm) + mm = &init_mm; + + ret = mem_cgroup_charge_common(page, mm, gfp_mask, + MEM_CGROUP_CHARGE_TYPE_CACHE); + return ret; +} + +/* + * Uncharging is always a welcome operation, we never complain, simply + * uncharge. This routine should be called with lock_page_cgroup held + */ +void mem_cgroup_uncharge(struct page_cgroup *pc) +{ + struct mem_cgroup *mem; + struct mem_cgroup_per_zone *mz; + struct page *page; + unsigned long flags; + + /* + * Check if our page_cgroup is valid + */ + if (!pc) + return; + + if (atomic_dec_and_test(&pc->ref_cnt)) { + page = pc->page; + mz = page_cgroup_zoneinfo(pc); + /* + * get page->cgroup and clear it under lock. + * force_empty can drop page->cgroup without checking refcnt. + */ + unlock_page_cgroup(page); + if (clear_page_cgroup(page, pc) == pc) { + mem = pc->mem_cgroup; + css_put(&mem->css); + res_counter_uncharge(&mem->res, PAGE_SIZE); + spin_lock_irqsave(&mz->lru_lock, flags); + __mem_cgroup_remove_list(pc); + spin_unlock_irqrestore(&mz->lru_lock, flags); + kfree(pc); + } + lock_page_cgroup(page); + } +} + +void mem_cgroup_uncharge_page(struct page *page) +{ + lock_page_cgroup(page); + mem_cgroup_uncharge(page_get_page_cgroup(page)); + unlock_page_cgroup(page); +} + +/* + * Returns non-zero if a page (under migration) has valid page_cgroup member. + * Refcnt of page_cgroup is incremented. + */ + +int mem_cgroup_prepare_migration(struct page *page) +{ + struct page_cgroup *pc; + int ret = 0; + lock_page_cgroup(page); + pc = page_get_page_cgroup(page); + if (pc && atomic_inc_not_zero(&pc->ref_cnt)) + ret = 1; + unlock_page_cgroup(page); + return ret; +} + +void mem_cgroup_end_migration(struct page *page) +{ + struct page_cgroup *pc; + + lock_page_cgroup(page); + pc = page_get_page_cgroup(page); + mem_cgroup_uncharge(pc); + unlock_page_cgroup(page); +} +/* + * We know both *page* and *newpage* are now not-on-LRU and Pg_locked. + * And no race with uncharge() routines because page_cgroup for *page* + * has extra one reference by mem_cgroup_prepare_migration. + */ + +void mem_cgroup_page_migration(struct page *page, struct page *newpage) +{ + struct page_cgroup *pc; + struct mem_cgroup *mem; + unsigned long flags; + struct mem_cgroup_per_zone *mz; +retry: + pc = page_get_page_cgroup(page); + if (!pc) + return; + mem = pc->mem_cgroup; + mz = page_cgroup_zoneinfo(pc); + if (clear_page_cgroup(page, pc) != pc) + goto retry; + spin_lock_irqsave(&mz->lru_lock, flags); + + __mem_cgroup_remove_list(pc); + spin_unlock_irqrestore(&mz->lru_lock, flags); + + pc->page = newpage; + lock_page_cgroup(newpage); + page_assign_page_cgroup(newpage, pc); + unlock_page_cgroup(newpage); + + mz = page_cgroup_zoneinfo(pc); + spin_lock_irqsave(&mz->lru_lock, flags); + __mem_cgroup_add_list(pc); + spin_unlock_irqrestore(&mz->lru_lock, flags); + return; +} + +/* + * This routine traverse page_cgroup in given list and drop them all. + * This routine ignores page_cgroup->ref_cnt. + * *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; + unsigned long flags; + struct list_head *list; + + if (active) + list = &mz->active_list; + else + list = &mz->inactive_list; + + if (list_empty(list)) + return; +retry: + count = FORCE_UNCHARGE_BATCH; + spin_lock_irqsave(&mz->lru_lock, flags); + + while (--count && !list_empty(list)) { + pc = list_entry(list->prev, struct page_cgroup, lru); + page = pc->page; + /* Avoid race with charge */ + atomic_set(&pc->ref_cnt, 0); + if (clear_page_cgroup(page, pc) == pc) { + css_put(&mem->css); + res_counter_uncharge(&mem->res, PAGE_SIZE); + __mem_cgroup_remove_list(pc); + kfree(pc); + } else /* being uncharged ? ...do relax */ + break; + } + spin_unlock_irqrestore(&mz->lru_lock, flags); + if (!list_empty(list)) { + cond_resched(); + goto retry; + } + return; +} + +/* + * make mem_cgroup's charge to be 0 if there is no task. + * This enables deleting this mem_cgroup. + */ + +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; +} + + + +int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp) +{ + *tmp = memparse(buf, &buf); + if (*buf != '\0') + return -EINVAL; + + /* + * Round up the value to the closest page size + */ + *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT; + return 0; +} + +static ssize_t mem_cgroup_read(struct cgroup *cont, + struct cftype *cft, struct file *file, + char __user *userbuf, size_t nbytes, loff_t *ppos) +{ + return res_counter_read(&mem_cgroup_from_cont(cont)->res, + cft->private, userbuf, nbytes, ppos, + NULL); +} + +static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft, + struct file *file, const char __user *userbuf, + size_t nbytes, loff_t *ppos) +{ + return res_counter_write(&mem_cgroup_from_cont(cont)->res, + cft->private, userbuf, nbytes, ppos, + mem_cgroup_write_strategy); +} + +static ssize_t mem_force_empty_write(struct cgroup *cont, + struct cftype *cft, struct file *file, + const char __user *userbuf, + size_t nbytes, loff_t *ppos) +{ + struct mem_cgroup *mem = mem_cgroup_from_cont(cont); + int ret; + ret = mem_cgroup_force_empty(mem); + if (!ret) + ret = nbytes; + return ret; +} + +/* + * Note: This should be removed if cgroup supports write-only file. + */ + +static ssize_t mem_force_empty_read(struct cgroup *cont, + struct cftype *cft, + struct file *file, char __user *userbuf, + size_t nbytes, loff_t *ppos) +{ + return -EINVAL; +} + + +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, }, +}; + +static int mem_control_stat_show(struct seq_file *m, void *arg) +{ + struct cgroup *cont = m->private; + 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; + seq_printf(m, "%s %lld\n", mem_cgroup_stat_desc[i].msg, + (long long)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); + seq_printf(m, "active %ld\n", (active) * PAGE_SIZE); + seq_printf(m, "inactive %ld\n", (inactive) * PAGE_SIZE); + } + return 0; +} + +static const struct file_operations mem_control_stat_file_operations = { + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int mem_control_stat_open(struct inode *unused, struct file *file) +{ + /* XXX __d_cont */ + struct cgroup *cont = file->f_dentry->d_parent->d_fsdata; + + file->f_op = &mem_control_stat_file_operations; + return single_open(file, mem_control_stat_show, cont); +} + + + +static struct cftype mem_cgroup_files[] = { + { + .name = "usage_in_bytes", + .private = RES_USAGE, + .read = mem_cgroup_read, + }, + { + .name = "limit_in_bytes", + .private = RES_LIMIT, + .write = mem_cgroup_write, + .read = mem_cgroup_read, + }, + { + .name = "failcnt", + .private = RES_FAILCNT, + .read = mem_cgroup_read, + }, + { + .name = "force_empty", + .write = mem_force_empty_write, + .read = mem_force_empty_read, + }, + { + .name = "stat", + .open = mem_control_stat_open, + }, +}; + +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; + /* + * 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_HIGH_MEMORY)) + pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, node); + else + pn = kmalloc(sizeof(*pn), GFP_KERNEL); + 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 init_mem_cgroup; + +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; + init_mm.mem_cgroup = mem; + } else + mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL); + + if (mem == NULL) + return NULL; + + res_counter_init(&mem->res); + + memset(&mem->info, 0, sizeof(mem->info)); + + 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) + kfree(mem); + return NULL; +} + +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); + + kfree(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 (p->tgid != p->pid) + goto out; + + css_get(&mem->css); + rcu_assign_pointer(mm->mem_cgroup, mem); + css_put(&old_mem->css); + +out: + mmput(mm); + return; +} + +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, +}; |