X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Fmemcontrol.c;h=964a70035e8f9ef24a8777e0db9c1c1d854a4273;hb=a7fe942e94b2f66aa0f11d37699c0ec8155d3ad1;hp=ac8774426fec37095f6868abd715cfd191698d01;hpb=e1a1cd590e3fcb0d2e230128daf2337ea55387dc;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ac87744..964a700 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -21,18 +21,99 @@ #include #include #include +#include +#include #include #include #include #include +#include +#include #include #include #include +#include +#include +#include +#include +#include "internal.h" #include -struct cgroup_subsys mem_cgroup_subsys; -static const int MEM_CGROUP_RECLAIM_RETRIES = 5; +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 + + +/* + * 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; +} + +/* + * 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]; +}; +/* 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 @@ -52,143 +133,299 @@ struct mem_cgroup { */ 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. - * TODO: Consider making these lists per zone */ - struct list_head active_list; - struct list_head inactive_list; + struct mem_cgroup_lru_info info; + + int prev_priority; /* for recording reclaim priority */ + + /* + * While reclaiming in a hiearchy, we cache the last child we + * reclaimed from. Protected by cgroup_lock() + */ + struct mem_cgroup *last_scanned_child; /* - * spin_lock to protect the per cgroup LRU + * Should the accounting and control be hierarchical, per subtree? + */ + bool use_hierarchy; + unsigned long last_oom_jiffies; + int obsolete; + atomic_t refcnt; + /* + * statistics. This must be placed at the end of memcg. */ - spinlock_t lru_lock; - unsigned long control_type; /* control RSS or RSS+Pagecache */ + 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 */ +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, }; -enum { - MEM_CGROUP_TYPE_UNSPEC = 0, - MEM_CGROUP_TYPE_MAPPED, - MEM_CGROUP_TYPE_CACHED, - MEM_CGROUP_TYPE_ALL, - MEM_CGROUP_TYPE_MAX, +/* 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 */ }; -static struct mem_cgroup init_mem_cgroup; -static inline -struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) +/* 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 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); + + return mem_cgroup_zoneinfo(mem, nid, zid); +} + +static unsigned long mem_cgroup_get_all_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); } -static inline 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); } -inline struct mem_cgroup *mm_cgroup(struct mm_struct *mm) +/* + * 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)) + return; + 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) { - return rcu_dereference(mm->mem_cgroup); + mem_cgroup_del_lru_list(page, page_lru(page)); } -void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p) +void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) { - struct mem_cgroup *mem; + struct mem_cgroup_per_zone *mz; + struct page_cgroup *pc; - mem = mem_cgroup_from_task(p); - css_get(&mem->css); - mm->mem_cgroup = mem; + if (mem_cgroup_disabled()) + return; + + pc = lookup_page_cgroup(page); + smp_rmb(); + /* unused page is not rotated. */ + if (!PageCgroupUsed(pc)) + return; + mz = page_cgroup_zoneinfo(pc); + list_move(&pc->lru, &mz->lists[lru]); } -void mm_free_cgroup(struct mm_struct *mm) +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); + /* barrier to sync with "charge" */ + smp_rmb(); + if (!PageCgroupUsed(pc)) + return; + + mz = page_cgroup_zoneinfo(pc); + MEM_CGROUP_ZSTAT(mz, lru) += 1; + list_add(&pc->lru, &mz->lists[lru]); +} +/* + * To add swapcache into LRU. Be careful to all this function. + * zone->lru_lock shouldn't be held and irq must not be disabled. + */ +static void mem_cgroup_lru_fixup(struct page *page) { - css_put(&mm->mem_cgroup->css); + if (!isolate_lru_page(page)) + putback_lru_page(page); } -static inline int page_cgroup_locked(struct page *page) +void mem_cgroup_move_lists(struct page *page, + enum lru_list from, enum lru_list to) { - return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, - &page->page_cgroup); + if (mem_cgroup_disabled()) + return; + mem_cgroup_del_lru_list(page, from); + mem_cgroup_add_lru_list(page, to); } -void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc) +int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) { - int locked; + int ret; - /* - * 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); + task_lock(task); + ret = task->mm && mm_match_cgroup(task->mm, mem); + task_unlock(task); + return ret; } -struct page_cgroup *page_get_page_cgroup(struct page *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) { - return (struct page_cgroup *) - (page->page_cgroup & ~PAGE_CGROUP_LOCK); + 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); } -static void __always_inline lock_page_cgroup(struct page *page) +/* + * prev_priority control...this will be used in memory reclaim path. + */ +int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem) { - bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); - VM_BUG_ON(!page_cgroup_locked(page)); + return mem->prev_priority; } -static void __always_inline unlock_page_cgroup(struct page *page) +void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority) { - bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); + if (priority < mem->prev_priority) + mem->prev_priority = priority; } -static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active) +void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority) { - if (active) - list_move(&pc->lru, &pc->mem_cgroup->active_list); - else - list_move(&pc->lru, &pc->mem_cgroup->inactive_list); + mem->prev_priority = priority; } /* - * This routine assumes that the appropriate zone's lru lock is already held + * 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) */ -void mem_cgroup_move_lists(struct page_cgroup *pc, bool active) + +long mem_cgroup_calc_reclaim(struct mem_cgroup *mem, struct zone *zone, + int priority, enum lru_list lru) { - struct mem_cgroup *mem; - if (!pc) - return; + long nr_pages; + int nid = zone->zone_pgdat->node_id; + int zid = zone_idx(zone); + struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid); - mem = pc->mem_cgroup; + nr_pages = MEM_CGROUP_ZSTAT(mz, lru); - spin_lock(&mem->lru_lock); - __mem_cgroup_move_lists(pc, active); - spin_unlock(&mem->lru_lock); + return (nr_pages >> priority); } unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, @@ -196,395 +433,1586 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, unsigned long *scanned, int order, int mode, struct zone *z, struct mem_cgroup *mem_cont, - int active) + 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; - - if (active) - src = &mem_cont->active_list; - else - src = &mem_cont->inactive_list; + 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; - spin_lock(&mem_cont->lru_lock); - for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { - pc = list_entry(src->prev, struct page_cgroup, lru); - page = pc->page; - VM_BUG_ON(!pc); + BUG_ON(!mem_cont); + mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); + src = &mz->lists[lru]; - if (PageActive(page) && !active) { - __mem_cgroup_move_lists(pc, true); - scan--; - continue; - } - if (!PageActive(page) && active) { - __mem_cgroup_move_lists(pc, false); - scan--; - continue; - } + scan = 0; + list_for_each_entry_safe_reverse(pc, tmp, src, lru) { + if (scan >= nr_to_scan) + break; - /* - * Reclaim, per zone - * TODO: make the active/inactive lists per zone - */ - if (page_zone(page) != z) + page = pc->page; + if (unlikely(!PageCgroupUsed(pc))) continue; - - /* - * Check if the meta page went away from under us - */ - if (!list_empty(&pc->lru)) - list_move(&pc->lru, &pc_list); - else + if (unlikely(!PageLRU(page))) continue; - if (__isolate_lru_page(page, mode) == 0) { + scan++; + if (__isolate_lru_page(page, mode, file) == 0) { list_move(&page->lru, dst); nr_taken++; } } - list_splice(&pc_list, src); - spin_unlock(&mem_cont->lru_lock); - *scanned = scan; return nr_taken; } +#define mem_cgroup_from_res_counter(counter, member) \ + container_of(counter, struct mem_cgroup, member) + /* - * Charge the memory controller for page usage. - * Return - * 0 if the charge was successful - * < 0 if the cgroup is over its limit + * This routine finds the DFS walk successor. This routine should be + * called with cgroup_mutex held */ -int mem_cgroup_charge(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask) +static struct mem_cgroup * +mem_cgroup_get_next_node(struct mem_cgroup *curr, struct mem_cgroup *root_mem) { - struct mem_cgroup *mem; - struct page_cgroup *pc, *race_pc; - unsigned long flags; - unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES; - - /* - * 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: - 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 - goto done; - } + struct cgroup *cgroup, *curr_cgroup, *root_cgroup; - unlock_page_cgroup(page); + curr_cgroup = curr->css.cgroup; + root_cgroup = root_mem->css.cgroup; - pc = kzalloc(sizeof(struct page_cgroup), gfp_mask); - if (pc == NULL) - goto err; + if (!list_empty(&curr_cgroup->children)) { + /* + * Walk down to children + */ + mem_cgroup_put(curr); + cgroup = list_entry(curr_cgroup->children.next, + struct cgroup, sibling); + curr = mem_cgroup_from_cont(cgroup); + mem_cgroup_get(curr); + goto done; + } - rcu_read_lock(); - /* - * 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; +visit_parent: + if (curr_cgroup == root_cgroup) { + mem_cgroup_put(curr); + curr = root_mem; + mem_cgroup_get(curr); + goto done; + } - mem = rcu_dereference(mm->mem_cgroup); /* - * For every charge from the cgroup, increment reference - * count + * Goto next sibling */ - css_get(&mem->css); - rcu_read_unlock(); + if (curr_cgroup->sibling.next != &curr_cgroup->parent->children) { + mem_cgroup_put(curr); + cgroup = list_entry(curr_cgroup->sibling.next, struct cgroup, + sibling); + curr = mem_cgroup_from_cont(cgroup); + mem_cgroup_get(curr); + goto done; + } /* - * If we created the page_cgroup, we should free it on exceeding - * the cgroup limit. + * Go up to next parent and next parent's sibling if need be */ - while (res_counter_charge(&mem->res, PAGE_SIZE)) { - bool is_atomic = gfp_mask & GFP_ATOMIC; - /* - * We cannot reclaim under GFP_ATOMIC, fail the charge - */ - if (is_atomic) - goto noreclaim; + curr_cgroup = curr_cgroup->parent; + goto visit_parent; - if (try_to_free_mem_cgroup_pages(mem, gfp_mask)) - continue; +done: + root_mem->last_scanned_child = curr; + return curr; +} - /* - * 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; - /* - * Since we control both RSS and cache, we end up with a - * very interesting scenario where we end up reclaiming - * memory (essentially RSS), since the memory is pushed - * to swap cache, we eventually end up adding those - * pages back to our list. Hence we give ourselves a - * few chances before we fail - */ - else if (nr_retries--) { - congestion_wait(WRITE, HZ/10); - continue; - } -noreclaim: - css_put(&mem->css); - if (!is_atomic) - mem_cgroup_out_of_memory(mem, GFP_KERNEL); - goto free_pc; - } +/* + * 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_get_first_node(struct mem_cgroup *root_mem) +{ + struct cgroup *cgroup; + struct mem_cgroup *ret; + bool obsolete = (root_mem->last_scanned_child && + root_mem->last_scanned_child->obsolete); - lock_page_cgroup(page); /* - * Check if somebody else beat us to allocating the page_cgroup + * Scan all children under the mem_cgroup mem */ - race_pc = page_get_page_cgroup(page); - if (race_pc) { - kfree(pc); - pc = race_pc; - atomic_inc(&pc->ref_cnt); - res_counter_uncharge(&mem->res, PAGE_SIZE); - css_put(&mem->css); + cgroup_lock(); + if (list_empty(&root_mem->css.cgroup->children)) { + ret = root_mem; goto done; } - atomic_set(&pc->ref_cnt, 1); - pc->mem_cgroup = mem; - pc->page = page; - page_assign_page_cgroup(page, pc); + if (!root_mem->last_scanned_child || obsolete) { + + if (obsolete) + mem_cgroup_put(root_mem->last_scanned_child); - spin_lock_irqsave(&mem->lru_lock, flags); - list_add(&pc->lru, &mem->active_list); - spin_unlock_irqrestore(&mem->lru_lock, flags); + cgroup = list_first_entry(&root_mem->css.cgroup->children, + struct cgroup, sibling); + ret = mem_cgroup_from_cont(cgroup); + mem_cgroup_get(ret); + } else + ret = mem_cgroup_get_next_node(root_mem->last_scanned_child, + root_mem); done: - unlock_page_cgroup(page); - return 0; -free_pc: - kfree(pc); -err: - return -ENOMEM; + root_mem->last_scanned_child = ret; + cgroup_unlock(); + return ret; } -/* - * 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) +static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem) { - struct mem_cgroup *mem; - if (!mm) - mm = &init_mm; - - mem = rcu_dereference(mm->mem_cgroup); - if (mem->control_type == MEM_CGROUP_TYPE_ALL) - return mem_cgroup_charge(page, mm, gfp_mask); - else - return 0; + 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; } /* - * Uncharging is always a welcome operation, we never complain, simply - * uncharge. + * Dance down 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. */ -void mem_cgroup_uncharge(struct page_cgroup *pc) +static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, + gfp_t gfp_mask, bool noswap) { - struct mem_cgroup *mem; - struct page *page; - unsigned long flags; + struct mem_cgroup *next_mem; + int ret = 0; /* - * This can handle cases when a page is not charged at all and we - * are switching between handling the control_type. + * Reclaim unconditionally and don't check for return value. + * We need to reclaim in the current group and down the tree. + * One might think about checking for children before reclaiming, + * but there might be left over accounting, even after children + * have left. */ - if (!pc) - return; + ret = try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap); + if (mem_cgroup_check_under_limit(root_mem)) + return 0; - if (atomic_dec_and_test(&pc->ref_cnt)) { - page = pc->page; - lock_page_cgroup(page); - mem = pc->mem_cgroup; - css_put(&mem->css); - page_assign_page_cgroup(page, NULL); - unlock_page_cgroup(page); - res_counter_uncharge(&mem->res, PAGE_SIZE); + next_mem = mem_cgroup_get_first_node(root_mem); - spin_lock_irqsave(&mem->lru_lock, flags); - list_del_init(&pc->lru); - spin_unlock_irqrestore(&mem->lru_lock, flags); - kfree(pc); + while (next_mem != root_mem) { + if (next_mem->obsolete) { + mem_cgroup_put(next_mem); + cgroup_lock(); + next_mem = mem_cgroup_get_first_node(root_mem); + cgroup_unlock(); + continue; + } + ret = try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap); + if (mem_cgroup_check_under_limit(root_mem)) + return 0; + cgroup_lock(); + next_mem = mem_cgroup_get_next_node(next_mem, root_mem); + cgroup_unlock(); } + return ret; } -int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp) +bool mem_cgroup_oom_called(struct task_struct *task) { - *tmp = memparse(buf, &buf); - if (*buf != '\0') - return -EINVAL; + bool ret = false; + struct mem_cgroup *mem; + struct mm_struct *mm; - /* - * Round up the value to the closest page size - */ - *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT; - return 0; + 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 ssize_t mem_cgroup_read(struct cgroup *cont, - struct cftype *cft, struct file *file, - char __user *userbuf, size_t nbytes, loff_t *ppos) +/* + * 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) { - return res_counter_read(&mem_cgroup_from_cont(cont)->res, - cft->private, userbuf, nbytes, ppos, - NULL); -} + struct mem_cgroup *mem, *mem_over_limit; + int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + struct res_counter *fail_res; -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); -} + if (unlikely(test_thread_flag(TIF_MEMDIE))) { + /* Don't account this! */ + *memcg = NULL; + return 0; + } -static ssize_t mem_control_type_write(struct cgroup *cont, - struct cftype *cft, struct file *file, - const char __user *userbuf, - size_t nbytes, loff_t *pos) -{ - int ret; - char *buf, *end; - unsigned long tmp; - struct mem_cgroup *mem; + /* + * 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)); + if (unlikely(!mem)) { + rcu_read_unlock(); + return 0; + } + /* + * For every charge from the cgroup, increment reference count + */ + css_get(&mem->css); + *memcg = mem; + rcu_read_unlock(); + } else { + mem = *memcg; + css_get(&mem->css); + } - mem = mem_cgroup_from_cont(cont); - buf = kmalloc(nbytes + 1, GFP_KERNEL); - ret = -ENOMEM; - if (buf == NULL) - goto out; + 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); - buf[nbytes] = 0; - ret = -EFAULT; - if (copy_from_user(buf, userbuf, nbytes)) - goto out_free; + if (!(gfp_mask & __GFP_WAIT)) + goto nomem; - ret = -EINVAL; - tmp = simple_strtoul(buf, &end, 10); - if (*end != '\0') - goto out_free; + ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask, + noswap); - if (tmp <= MEM_CGROUP_TYPE_UNSPEC || tmp >= MEM_CGROUP_TYPE_MAX) - goto out_free; + /* + * 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; - mem->control_type = tmp; - ret = nbytes; -out_free: - kfree(buf); -out: - return ret; + if (!nr_retries--) { + if (oom) { + mem_cgroup_out_of_memory(mem_over_limit, gfp_mask); + mem_over_limit->last_oom_jiffies = jiffies; + } + goto nomem; + } + } + return 0; +nomem: + css_put(&mem->css); + return -ENOMEM; } -static ssize_t mem_control_type_read(struct cgroup *cont, - struct cftype *cft, - struct file *file, char __user *userbuf, - size_t nbytes, loff_t *ppos) -{ - unsigned long val; - char buf[64], *s; - struct mem_cgroup *mem; +/** + * mem_cgroup_try_charge - get charge of PAGE_SIZE. + * @mm: an mm_struct which is charged against. (when *memcg is NULL) + * @gfp_mask: gfp_mask for reclaim. + * @memcg: a pointer to memory cgroup which is charged against. + * + * charge against memory cgroup pointed by *memcg. if *memcg == NULL, estimated + * memory cgroup from @mm is got and stored in *memcg. + * + * Returns 0 if success. -ENOMEM at failure. + * This call can invoke OOM-Killer. + */ + +int mem_cgroup_try_charge(struct mm_struct *mm, + gfp_t mask, struct mem_cgroup **memcg) +{ + return __mem_cgroup_try_charge(mm, mask, memcg, true); +} + +/* + * 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; + + css_put(&from->css); + 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); + pc->mem_cgroup = to; + mem_cgroup_charge_statistics(to, pc, true); + css_get(&to->css); + 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)) + return -EBUSY; + + ret = isolate_lru_page(page); + + if (ret) + goto cancel; + + ret = mem_cgroup_move_account(pc, child, parent); + + /* drop extra refcnt by try_charge() (move_account increment one) */ + css_put(&parent->css); + putback_lru_page(page); + if (!ret) { + put_page(page); + return 0; + } + /* uncharge if move fails */ +cancel: + res_counter_uncharge(&parent->res, PAGE_SIZE); + if (do_swap_account) + res_counter_uncharge(&parent->memsw, PAGE_SIZE); + put_page(page); + 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); +} + +int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, + gfp_t gfp_mask) +{ + 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.) + */ + 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)) + mm = &init_mm; + + if (page_is_file_cache(page)) + return mem_cgroup_charge_common(page, mm, gfp_mask, + MEM_CGROUP_CHARGE_TYPE_CACHE, NULL); + else + return mem_cgroup_charge_common(page, mm, gfp_mask, + MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL); +} + +int mem_cgroup_try_charge_swapin(struct mm_struct *mm, + struct page *page, + gfp_t mask, struct mem_cgroup **ptr) +{ + struct mem_cgroup *mem; + swp_entry_t ent; + + 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; + + ent.val = page_private(page); + + mem = lookup_swap_cgroup(ent); + if (!mem || mem->obsolete) + goto charge_cur_mm; + *ptr = mem; + return __mem_cgroup_try_charge(NULL, mask, ptr, true); +charge_cur_mm: + if (unlikely(!mm)) + mm = &init_mm; + return __mem_cgroup_try_charge(mm, mask, ptr, true); +} + +#ifdef CONFIG_SWAP + +int mem_cgroup_cache_charge_swapin(struct page *page, + struct mm_struct *mm, gfp_t mask, bool locked) +{ + int ret = 0; + + if (mem_cgroup_disabled()) + return 0; + if (unlikely(!mm)) + mm = &init_mm; + if (!locked) + lock_page(page); + /* + * If not locked, the page can be dropped from SwapCache until + * we reach here. + */ + if (PageSwapCache(page)) { + struct mem_cgroup *mem = NULL; + swp_entry_t ent; + + ent.val = page_private(page); + if (do_swap_account) { + mem = lookup_swap_cgroup(ent); + if (mem && mem->obsolete) + mem = NULL; + if (mem) + mm = NULL; + } + ret = mem_cgroup_charge_common(page, mm, mask, + MEM_CGROUP_CHARGE_TYPE_SHMEM, mem); + + if (!ret && do_swap_account) { + /* avoid double counting */ + mem = swap_cgroup_record(ent, NULL); + if (mem) { + res_counter_uncharge(&mem->memsw, PAGE_SIZE); + mem_cgroup_put(mem); + } + } + } + if (!locked) + unlock_page(page); + /* add this page(page_cgroup) to the LRU we want. */ + mem_cgroup_lru_fixup(page); + + return ret; +} +#endif + +void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) +{ + struct page_cgroup *pc; + + if (mem_cgroup_disabled()) + return; + if (!ptr) + return; + pc = lookup_page_cgroup(page); + __mem_cgroup_commit_charge(ptr, pc, MEM_CGROUP_CHARGE_TYPE_MAPPED); + /* + * 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. This SwapCache is stable + * because we're still under lock_page(). + */ + if (do_swap_account) { + swp_entry_t ent = {.val = page_private(page)}; + struct mem_cgroup *memcg; + memcg = swap_cgroup_record(ent, NULL); + if (memcg) { + /* If memcg is obsolete, memcg can be != ptr */ + res_counter_uncharge(&memcg->memsw, PAGE_SIZE); + mem_cgroup_put(memcg); + } + + } + /* add this page(page_cgroup) to the LRU we want. */ + mem_cgroup_lru_fixup(page); +} + +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); + + 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); +} + +/* + * called from __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, memcg); + mem_cgroup_get(memcg); + } + if (memcg) + css_put(&memcg->css); +} + +#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; + + if (!do_swap_account) + return; + + memcg = swap_cgroup_record(ent, NULL); + if (memcg) { + res_counter_uncharge(&memcg->memsw, PAGE_SIZE); + mem_cgroup_put(memcg); + } +} +#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); + 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 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_disabled()) + return 0; + if (!mm) + return 0; + + rcu_read_lock(); + mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (unlikely(!mem)) { + rcu_read_unlock(); + return 0; + } + css_get(&mem->css); + rcu_read_unlock(); + + do { + progress = try_to_free_mem_cgroup_pages(mem, gfp_mask, true); + progress += mem_cgroup_check_under_limit(mem); + } while (!progress && --retry); + + css_put(&mem->css); + if (!retry) + return -ENOMEM; + return 0; +} + +static DEFINE_MUTEX(set_limit_mutex); + +static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, + unsigned long long val) +{ + + int retry_count = MEM_CGROUP_RECLAIM_RETRIES; + int progress; + u64 memswlimit; + int ret = 0; + + 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 = try_to_free_mem_cgroup_pages(memcg, + GFP_KERNEL, false); + if (!progress) retry_count--; + } + return ret; +} + +int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, + unsigned long long val) +{ + int retry_count = MEM_CGROUP_RECLAIM_RETRIES; + u64 memlimit, oldusage, curusage; + int ret; + + if (!do_swap_account) + return -EINVAL; + + 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; + + oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); + try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL, true); + curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); + if (curusage >= oldusage) + 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. + */ +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_POSSIBLE) { + 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); + 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 int mem_cgroup_reset(struct cgroup *cont, unsigned int event) +{ + struct mem_cgroup *mem; + int type, name; mem = mem_cgroup_from_cont(cont); - s = buf; - val = mem->control_type; - s += sprintf(s, "%lu\n", val); - return simple_read_from_buffer((void __user *)userbuf, nbytes, - ppos, buf, s - buf); + 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; } +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_anon, inactive_anon; + unsigned long active_file, inactive_file; + unsigned long unevictable; + + inactive_anon = mem_cgroup_get_all_zonestat(mem_cont, + LRU_INACTIVE_ANON); + active_anon = mem_cgroup_get_all_zonestat(mem_cont, + LRU_ACTIVE_ANON); + inactive_file = mem_cgroup_get_all_zonestat(mem_cont, + LRU_INACTIVE_FILE); + active_file = mem_cgroup_get_all_zonestat(mem_cont, + LRU_ACTIVE_FILE); + unevictable = mem_cgroup_get_all_zonestat(mem_cont, + LRU_UNEVICTABLE); + + cb->fill(cb, "active_anon", (active_anon) * PAGE_SIZE); + cb->fill(cb, "inactive_anon", (inactive_anon) * PAGE_SIZE); + cb->fill(cb, "active_file", (active_file) * PAGE_SIZE); + cb->fill(cb, "inactive_file", (inactive_file) * PAGE_SIZE); + cb->fill(cb, "unevictable", unevictable * PAGE_SIZE); + + } + return 0; +} + + static struct cftype mem_cgroup_files[] = { { .name = "usage_in_bytes", - .private = RES_USAGE, - .read = mem_cgroup_read, + .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 = RES_LIMIT, - .write = mem_cgroup_write, - .read = mem_cgroup_read, + .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), + .write_string = mem_cgroup_write, + .read_u64 = mem_cgroup_read, }, { .name = "failcnt", - .private = RES_FAILCNT, - .read = mem_cgroup_read, + .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, + }, +}; + +#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 = "control_type", - .write = mem_control_type_write, - .read = mem_control_type_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 struct mem_cgroup init_mem_cgroup; +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. + * + * When mem_cgroup is destroyed, mem->obsolete will be set to 0 and + * entry which points to this memcg will be ignore at swapin. + * + * Removal of cgroup itself succeeds regardless of refs from swap. + */ + +static void mem_cgroup_free(struct mem_cgroup *mem) +{ + int node; + + if (atomic_read(&mem->refcnt) > 0) + return; + + + 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)) { + if (!mem->obsolete) + return; + mem_cgroup_free(mem); + } +} + + +#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 * mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) { - struct mem_cgroup *mem; + struct mem_cgroup *mem, *parent; + int node; + + mem = mem_cgroup_alloc(); + if (!mem) + return ERR_PTR(-ENOMEM); + + 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 (unlikely((cont->parent) == NULL)) { - mem = &init_mem_cgroup; - init_mm.mem_cgroup = mem; - } else - mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL); + if (parent && parent->use_hierarchy) { + res_counter_init(&mem->res, &parent->res); + res_counter_init(&mem->memsw, &parent->memsw); + } else { + res_counter_init(&mem->res, NULL); + res_counter_init(&mem->memsw, NULL); + } - if (mem == NULL) - return NULL; + mem->last_scanned_child = NULL; - res_counter_init(&mem->res); - INIT_LIST_HEAD(&mem->active_list); - INIT_LIST_HEAD(&mem->inactive_list); - spin_lock_init(&mem->lru_lock); - mem->control_type = MEM_CGROUP_TYPE_ALL; return &mem->css; +free_out: + for_each_node_state(node, N_POSSIBLE) + free_mem_cgroup_per_zone_info(mem, node); + 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->obsolete = 1; + mem_cgroup_force_empty(mem, false); } static void mem_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cont) { - kfree(mem_cgroup_from_cont(cont)); + 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)); + 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, @@ -592,41 +2020,29 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss, 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 + * FIXME: It's better to move charges of this process from old + * memcg to new memcg. But it's just on TODO-List now. */ - 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 = 1, + .early_init = 0, }; + +#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