X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=mm%2Fmemcontrol.c;h=23b5fa4cabd8d7310b4adc3043f3c5232c47fa22;hb=79bc14813cd7e1b75d2e4cbbc17043261cf4bcdc;hp=631002d085d1374dfdfe734f761aaf3e6a65dde3;hpb=35d77ef1c05bc3760427954dafaee3ca550542f3;p=linux-2.6-omap-h63xx.git diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 631002d085d..23b5fa4cabd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -137,14 +137,21 @@ struct mem_cgroup { */ 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 atleast two - * byte aligned (based on comments from Nick Piggin) + * 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 -#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT) +#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 @@ -154,37 +161,27 @@ 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; + int ref_cnt; /* cached, mapped, migrating */ + 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) +static 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) +static 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() */ @@ -193,23 +190,21 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags, { int val = (charge)? 1 : -1; struct mem_cgroup_stat *stat = &mem->stat; - VM_BUG_ON(!irqs_disabled()); + VM_BUG_ON(!irqs_disabled()); if (flags & PAGE_CGROUP_FLAG_CACHE) - __mem_cgroup_stat_add_safe(stat, - MEM_CGROUP_STAT_CACHE, val); + __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 * +static 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 * +static struct mem_cgroup_per_zone * page_cgroup_zoneinfo(struct page_cgroup *pc) { struct mem_cgroup *mem = pc->mem_cgroup; @@ -234,18 +229,14 @@ static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem, return total; } -static struct mem_cgroup init_mem_cgroup; - -static inline -struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) +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) +static 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); @@ -267,81 +258,33 @@ void mm_free_cgroup(struct mm_struct *mm) static inline int page_cgroup_locked(struct page *page) { - return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, - &page->page_cgroup); + return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); } -void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc) +static 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); + 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); + return (struct page_cgroup *) (page->page_cgroup & ~PAGE_CGROUP_LOCK); } -static void __always_inline lock_page_cgroup(struct page *page) +static void 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) +static int try_lock_page_cgroup(struct page *page) { - 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; + return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); } -/* - * 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) +static void unlock_page_cgroup(struct page *page) { - 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; + bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); } static void __mem_cgroup_remove_list(struct page_cgroup *pc) @@ -399,7 +342,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) int ret; task_lock(task); - ret = task->mm && vm_match_cgroup(task->mm, mem); + ret = task->mm && mm_match_cgroup(task->mm, mem); task_unlock(task); return ret; } @@ -407,18 +350,30 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) /* * This routine assumes that the appropriate zone's lru lock is already held */ -void mem_cgroup_move_lists(struct page_cgroup *pc, bool active) +void mem_cgroup_move_lists(struct page *page, bool active) { + struct page_cgroup *pc; struct mem_cgroup_per_zone *mz; unsigned long flags; - if (!pc) + /* + * 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; - 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); + 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); } /* @@ -437,6 +392,7 @@ int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem) 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 @@ -500,7 +456,6 @@ long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem, 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); } @@ -578,6 +533,9 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES; struct mem_cgroup_per_zone *mz; + if (mem_cgroup_subsys.disabled) + return 0; + /* * Should page_cgroup's go to their own slab? * One could optimize the performance of the charging routine @@ -586,26 +544,21 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, * 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; - } - } + lock_page_cgroup(page); + pc = page_get_page_cgroup(page); + /* + * The page_cgroup exists and + * the page has already been accounted. + */ + if (pc) { + VM_BUG_ON(pc->page != page); + VM_BUG_ON(pc->ref_cnt <= 0); + + pc->ref_cnt++; unlock_page_cgroup(page); + goto done; } + unlock_page_cgroup(page); pc = kzalloc(sizeof(struct page_cgroup), gfp_mask); if (pc == NULL) @@ -623,16 +576,11 @@ retry: rcu_read_lock(); mem = rcu_dereference(mm->mem_cgroup); /* - * For every charge from the cgroup, increment reference - * count + * 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; @@ -641,12 +589,12 @@ retry: 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 - */ + * 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; @@ -657,14 +605,16 @@ retry: congestion_wait(WRITE, HZ/10); } - atomic_set(&pc->ref_cnt, 1); + 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)) { + lock_page_cgroup(page); + if (page_get_page_cgroup(page)) { + unlock_page_cgroup(page); /* * Another charge has been added to this page already. * We take lock_page_cgroup(page) again and read @@ -673,17 +623,16 @@ retry: res_counter_uncharge(&mem->res, PAGE_SIZE); css_put(&mem->css); kfree(pc); - if (!page) - goto done; goto retry; } + page_assign_page_cgroup(page, pc); 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); + unlock_page_cgroup(page); done: return 0; out: @@ -693,70 +642,64 @@ err: return -ENOMEM; } -int mem_cgroup_charge(struct page *page, struct mm_struct *mm, - gfp_t gfp_mask) +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); + 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, + return 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 + * uncharge. */ -void mem_cgroup_uncharge(struct page_cgroup *pc) +void mem_cgroup_uncharge_page(struct page *page) { + struct page_cgroup *pc; struct mem_cgroup *mem; struct mem_cgroup_per_zone *mz; - struct page *page; 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 (!pc) - return; + goto unlock; - if (atomic_dec_and_test(&pc->ref_cnt)) { - page = pc->page; + VM_BUG_ON(pc->page != page); + VM_BUG_ON(pc->ref_cnt <= 0); + + if (--(pc->ref_cnt) == 0) { mz = page_cgroup_zoneinfo(pc); - /* - * get page->cgroup and clear it under lock. - * force_empty can drop page->cgroup without checking refcnt. - */ + spin_lock_irqsave(&mz->lru_lock, flags); + __mem_cgroup_remove_list(pc); + spin_unlock_irqrestore(&mz->lru_lock, flags); + + page_assign_page_cgroup(page, NULL); 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); + + mem = pc->mem_cgroup; + res_counter_uncharge(&mem->res, PAGE_SIZE); + css_put(&mem->css); + + kfree(pc); + return; } -} -void mem_cgroup_uncharge_page(struct page *page) -{ - lock_page_cgroup(page); - mem_cgroup_uncharge(page_get_page_cgroup(page)); +unlock: unlock_page_cgroup(page); } @@ -764,63 +707,62 @@ void mem_cgroup_uncharge_page(struct page *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; + + if (mem_cgroup_subsys.disabled) + return 0; + lock_page_cgroup(page); pc = page_get_page_cgroup(page); - if (pc && atomic_inc_not_zero(&pc->ref_cnt)) - ret = 1; + if (pc) + pc->ref_cnt++; unlock_page_cgroup(page); - return ret; + return pc != NULL; } 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); + mem_cgroup_uncharge_page(page); } + /* - * We know both *page* and *newpage* are now not-on-LRU and Pg_locked. + * 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: + unsigned long flags; + + lock_page_cgroup(page); pc = page_get_page_cgroup(page); - if (!pc) + if (!pc) { + unlock_page_cgroup(page); 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); + page_assign_page_cgroup(page, NULL); + unlock_page_cgroup(page); + 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; + + unlock_page_cgroup(newpage); } /* @@ -829,14 +771,13 @@ retry: * *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, +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; + int count = FORCE_UNCHARGE_BATCH; unsigned long flags; struct list_head *list; @@ -845,46 +786,39 @@ mem_cgroup_force_empty_list(struct mem_cgroup *mem, 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)) { + while (!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; + get_page(page); + spin_unlock_irqrestore(&mz->lru_lock, flags); + mem_cgroup_uncharge_page(page); + put_page(page); + if (--count <= 0) { + count = FORCE_UNCHARGE_BATCH; + cond_resched(); + } + spin_lock_irqsave(&mz->lru_lock, flags); } 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) +static int mem_cgroup_force_empty(struct mem_cgroup *mem) { int ret = -EBUSY; int node, zid; + + if (mem_cgroup_subsys.disabled) + return 0; + css_get(&mem->css); /* * page reclaim code (kswapd etc..) will move pages between -` * active_list <-> inactive_list while we don't take a lock. + * 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) { @@ -906,9 +840,7 @@ out: return ret; } - - -int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp) +static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp) { *tmp = memparse(buf, &buf); if (*buf != '\0') @@ -945,8 +877,7 @@ static ssize_t mem_force_empty_write(struct cgroup *cont, size_t nbytes, loff_t *ppos) { struct mem_cgroup *mem = mem_cgroup_from_cont(cont); - int ret; - ret = mem_cgroup_force_empty(mem); + int ret = mem_cgroup_force_empty(mem); if (!ret) ret = nbytes; return ret; @@ -955,7 +886,6 @@ static ssize_t mem_force_empty_write(struct cgroup *cont, /* * 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, @@ -964,7 +894,6 @@ static ssize_t mem_force_empty_read(struct cgroup *cont, return -EINVAL; } - static const struct mem_cgroup_stat_desc { const char *msg; u64 unit; @@ -1017,8 +946,6 @@ static int mem_control_stat_open(struct inode *unused, struct file *file) return single_open(file, mem_control_stat_show, cont); } - - static struct cftype mem_cgroup_files[] = { { .name = "usage_in_bytes", @@ -1084,9 +1011,6 @@ 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) { @@ -1141,6 +1065,8 @@ static void mem_cgroup_destroy(struct cgroup_subsys *ss, static int mem_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) { + if (mem_cgroup_subsys.disabled) + return 0; return cgroup_add_files(cont, ss, mem_cgroup_files, ARRAY_SIZE(mem_cgroup_files)); } @@ -1153,6 +1079,9 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss, struct mm_struct *mm; struct mem_cgroup *mem, *old_mem; + if (mem_cgroup_subsys.disabled) + return; + mm = get_task_mm(p); if (mm == NULL) return; @@ -1167,7 +1096,7 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss, * Only thread group leaders are allowed to migrate, the mm_struct is * in effect owned by the leader */ - if (p->tgid != p->pid) + if (!thread_group_leader(p)) goto out; css_get(&mem->css); @@ -1176,7 +1105,6 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss, out: mmput(mm); - return; } struct cgroup_subsys mem_cgroup_subsys = {