diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/hugetlb_cgroup.c | 11 | ||||
| -rw-r--r-- | mm/memcontrol.c | 181 |
2 files changed, 93 insertions, 99 deletions
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index a3f358f..0d3a1a3 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -155,18 +155,13 @@ out: * Force the hugetlb cgroup to empty the hugetlb resources by moving them to * the parent cgroup. */ -static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup) +static void hugetlb_cgroup_pre_destroy(struct cgroup *cgroup) { struct hstate *h; struct page *page; - int ret = 0, idx = 0; + int idx = 0; do { - if (cgroup_task_count(cgroup) || - !list_empty(&cgroup->children)) { - ret = -EBUSY; - goto out; - } for_each_hstate(h) { spin_lock(&hugetlb_lock); list_for_each_entry(page, &h->hugepage_activelist, lru) @@ -177,8 +172,6 @@ static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup) } cond_resched(); } while (hugetlb_cgroup_have_usage(cgroup)); -out: - return ret; } int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages, diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7acf43b..08adaaa 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2337,7 +2337,6 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, again: if (*ptr) { /* css should be a valid one */ memcg = *ptr; - VM_BUG_ON(css_is_removed(&memcg->css)); if (mem_cgroup_is_root(memcg)) goto done; if (nr_pages == 1 && consume_stock(memcg)) @@ -2477,9 +2476,9 @@ static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg, /* * A helper function to get mem_cgroup from ID. must be called under - * rcu_read_lock(). The caller must check css_is_removed() or some if - * it's concern. (dropping refcnt from swap can be called against removed - * memcg.) + * rcu_read_lock(). The caller is responsible for calling css_tryget if + * the mem_cgroup is used for charging. (dropping refcnt from swap can be + * called against removed memcg.) */ static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) { @@ -2676,13 +2675,6 @@ static int mem_cgroup_move_account(struct page *page, /* caller should have done css_get */ pc->mem_cgroup = to; mem_cgroup_charge_statistics(to, anon, nr_pages); - /* - * We charges against "to" which may not have any tasks. Then, "to" - * can be under rmdir(). But in current implementation, caller of - * this function is just force_empty() and move charge, so it's - * guaranteed that "to" is never removed. So, we don't check rmdir - * status here. - */ move_unlock_mem_cgroup(from, &flags); ret = 0; unlock: @@ -2696,10 +2688,27 @@ out: return ret; } -/* - * move charges to its parent. +/** + * mem_cgroup_move_parent - moves page to the parent group + * @page: the page to move + * @pc: page_cgroup of the page + * @child: page's cgroup + * + * move charges to its parent or the root cgroup if the group has no + * parent (aka use_hierarchy==0). + * Although this might fail (get_page_unless_zero, isolate_lru_page or + * mem_cgroup_move_account fails) the failure is always temporary and + * it signals a race with a page removal/uncharge or migration. In the + * first case the page is on the way out and it will vanish from the LRU + * on the next attempt and the call should be retried later. + * Isolation from the LRU fails only if page has been isolated from + * the LRU since we looked at it and that usually means either global + * reclaim or migration going on. The page will either get back to the + * LRU or vanish. + * Finaly mem_cgroup_move_account fails only if the page got uncharged + * (!PageCgroupUsed) or moved to a different group. The page will + * disappear in the next attempt. */ - static int mem_cgroup_move_parent(struct page *page, struct page_cgroup *pc, struct mem_cgroup *child) @@ -2709,9 +2718,7 @@ static int mem_cgroup_move_parent(struct page *page, unsigned long uninitialized_var(flags); int ret; - /* Is ROOT ? */ - if (mem_cgroup_is_root(child)) - return -EINVAL; + VM_BUG_ON(mem_cgroup_is_root(child)); ret = -EBUSY; if (!get_page_unless_zero(page)) @@ -2728,8 +2735,10 @@ static int mem_cgroup_move_parent(struct page *page, if (!parent) parent = root_mem_cgroup; - if (nr_pages > 1) + if (nr_pages > 1) { + VM_BUG_ON(!PageTransHuge(page)); flags = compound_lock_irqsave(page); + } ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent); @@ -2871,7 +2880,6 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg, return; if (!memcg) return; - cgroup_exclude_rmdir(&memcg->css); __mem_cgroup_commit_charge(memcg, page, 1, ctype, true); /* @@ -2885,12 +2893,6 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg, swp_entry_t ent = {.val = page_private(page)}; mem_cgroup_uncharge_swap(ent); } - /* - * At swapin, we may charge account against cgroup which has no tasks. - * So, rmdir()->pre_destroy() can be called while we do this charge. - * In that case, we need to call pre_destroy() again. check it here. - */ - cgroup_release_and_wakeup_rmdir(&memcg->css); } void mem_cgroup_commit_charge_swapin(struct page *page, @@ -3338,8 +3340,7 @@ void mem_cgroup_end_migration(struct mem_cgroup *memcg, if (!memcg) return; - /* blocks rmdir() */ - cgroup_exclude_rmdir(&memcg->css); + if (!migration_ok) { used = oldpage; unused = newpage; @@ -3373,13 +3374,6 @@ void mem_cgroup_end_migration(struct mem_cgroup *memcg, */ if (anon) mem_cgroup_uncharge_page(used); - /* - * At migration, we may charge account against cgroup which has no - * tasks. - * So, rmdir()->pre_destroy() can be called while we do this charge. - * In that case, we need to call pre_destroy() again. check it here. - */ - cgroup_release_and_wakeup_rmdir(&memcg->css); } /* @@ -3679,17 +3673,22 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, return nr_reclaimed; } -/* +/** + * mem_cgroup_force_empty_list - clears LRU of a group + * @memcg: group to clear + * @node: NUMA node + * @zid: zone id + * @lru: lru to to clear + * * Traverse a specified page_cgroup list and try to drop them all. This doesn't - * reclaim the pages page themselves - it just removes the page_cgroups. - * Returns true if some page_cgroups were not freed, indicating that the caller - * must retry this operation. + * reclaim the pages page themselves - pages are moved to the parent (or root) + * group. */ -static bool mem_cgroup_force_empty_list(struct mem_cgroup *memcg, +static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg, int node, int zid, enum lru_list lru) { struct mem_cgroup_per_zone *mz; - unsigned long flags, loop; + unsigned long flags; struct list_head *list; struct page *busy; struct zone *zone; @@ -3698,11 +3697,8 @@ static bool mem_cgroup_force_empty_list(struct mem_cgroup *memcg, mz = mem_cgroup_zoneinfo(memcg, node, zid); list = &mz->lruvec.lists[lru]; - loop = mz->lru_size[lru]; - /* give some margin against EBUSY etc...*/ - loop += 256; busy = NULL; - while (loop--) { + do { struct page_cgroup *pc; struct page *page; @@ -3728,76 +3724,72 @@ static bool mem_cgroup_force_empty_list(struct mem_cgroup *memcg, cond_resched(); } else busy = NULL; - } - return !list_empty(list); + } while (!list_empty(list)); } /* - * make mem_cgroup's charge to be 0 if there is no task. + * make mem_cgroup's charge to be 0 if there is no task by moving + * all the charges and pages to the parent. * This enables deleting this mem_cgroup. + * + * Caller is responsible for holding css reference on the memcg. */ -static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all) +static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg) { - int ret; - int node, zid, shrink; - int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; - struct cgroup *cgrp = memcg->css.cgroup; - - css_get(&memcg->css); + int node, zid; - shrink = 0; - /* should free all ? */ - if (free_all) - goto try_to_free; -move_account: do { - ret = -EBUSY; - if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) - goto out; /* This is for making all *used* pages to be on LRU. */ lru_add_drain_all(); drain_all_stock_sync(memcg); - ret = 0; mem_cgroup_start_move(memcg); for_each_node_state(node, N_HIGH_MEMORY) { - for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) { + for (zid = 0; zid < MAX_NR_ZONES; zid++) { enum lru_list lru; for_each_lru(lru) { - ret = mem_cgroup_force_empty_list(memcg, + mem_cgroup_force_empty_list(memcg, node, zid, lru); - if (ret) - break; } } - if (ret) - break; } mem_cgroup_end_move(memcg); memcg_oom_recover(memcg); cond_resched(); - /* "ret" should also be checked to ensure all lists are empty. */ - } while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret); -out: - css_put(&memcg->css); - return ret; -try_to_free: + /* + * This is a safety check because mem_cgroup_force_empty_list + * could have raced with mem_cgroup_replace_page_cache callers + * so the lru seemed empty but the page could have been added + * right after the check. RES_USAGE should be safe as we always + * charge before adding to the LRU. + */ + } while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0); +} + +/* + * Reclaims as many pages from the given memcg as possible and moves + * the rest to the parent. + * + * Caller is responsible for holding css reference for memcg. + */ +static int mem_cgroup_force_empty(struct mem_cgroup *memcg) +{ + int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; + struct cgroup *cgrp = memcg->css.cgroup; + /* 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; - } + if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) + return -EBUSY; + /* 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 && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) { int progress; - if (signal_pending(current)) { - ret = -EINTR; - goto out; - } + if (signal_pending(current)) + return -EINTR; + progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL, false); if (!progress) { @@ -3808,13 +3800,23 @@ try_to_free: } lru_add_drain(); - /* try move_account...there may be some *locked* pages. */ - goto move_account; + mem_cgroup_reparent_charges(memcg); + + return 0; } static int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) { - return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); + struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); + int ret; + + if (mem_cgroup_is_root(memcg)) + return -EINVAL; + css_get(&memcg->css); + ret = mem_cgroup_force_empty(memcg); + css_put(&memcg->css); + + return ret; } @@ -5001,11 +5003,11 @@ free_out: return ERR_PTR(error); } -static int mem_cgroup_pre_destroy(struct cgroup *cont) +static void mem_cgroup_pre_destroy(struct cgroup *cont) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - return mem_cgroup_force_empty(memcg, false); + mem_cgroup_reparent_charges(memcg); } static void mem_cgroup_destroy(struct cgroup *cont) @@ -5607,7 +5609,6 @@ struct cgroup_subsys mem_cgroup_subsys = { .base_cftypes = mem_cgroup_files, .early_init = 0, .use_id = 1, - .__DEPRECATED_clear_css_refs = true, }; #ifdef CONFIG_MEMCG_SWAP |
