diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memcontrol.c | 123 |
1 files changed, 54 insertions, 69 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c74102d6eb5a..ff051ee8fb4b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1040,30 +1040,7 @@ struct lruvec *mem_cgroup_lru_add_list(struct zone *zone, struct page *page, return &zone->lruvec; pc = lookup_page_cgroup(page); - VM_BUG_ON(PageCgroupAcctLRU(pc)); - /* - * putback: charge: - * SetPageLRU SetPageCgroupUsed - * smp_mb smp_mb - * PageCgroupUsed && add to memcg LRU PageLRU && add to memcg LRU - * - * Ensure that one of the two sides adds the page to the memcg - * LRU during a race. - */ - smp_mb(); - /* - * If the page is uncharged, it may be freed soon, but it - * could also be swap cache (readahead, swapoff) that needs to - * be reclaimable in the future. root_mem_cgroup will babysit - * it for the time being. - */ - if (PageCgroupUsed(pc)) { - /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ - smp_rmb(); - memcg = pc->mem_cgroup; - SetPageCgroupAcctLRU(pc); - } else - memcg = root_mem_cgroup; + memcg = pc->mem_cgroup; mz = page_cgroup_zoneinfo(memcg, page); /* compound_order() is stabilized through lru_lock */ MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page); @@ -1090,18 +1067,8 @@ void mem_cgroup_lru_del_list(struct page *page, enum lru_list lru) return; pc = lookup_page_cgroup(page); - /* - * root_mem_cgroup babysits uncharged LRU pages, but - * PageCgroupUsed is cleared when the page is about to get - * freed. PageCgroupAcctLRU remembers whether the - * LRU-accounting happened against pc->mem_cgroup or - * root_mem_cgroup. - */ - if (TestClearPageCgroupAcctLRU(pc)) { - VM_BUG_ON(!pc->mem_cgroup); - memcg = pc->mem_cgroup; - } else - memcg = root_mem_cgroup; + memcg = pc->mem_cgroup; + VM_BUG_ON(!memcg); mz = page_cgroup_zoneinfo(memcg, page); /* huge page split is done under lru_lock. so, we have no races. */ MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page); @@ -2217,8 +2184,25 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, } /* - * Unlike exported interface, "oom" parameter is added. if oom==true, - * oom-killer can be invoked. + * __mem_cgroup_try_charge() does + * 1. detect memcg to be charged against from passed *mm and *ptr, + * 2. update res_counter + * 3. call memory reclaim if necessary. + * + * In some special case, if the task is fatal, fatal_signal_pending() or + * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup + * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon + * as possible without any hazards. 2: all pages should have a valid + * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg + * pointer, that is treated as a charge to root_mem_cgroup. + * + * So __mem_cgroup_try_charge() will return + * 0 ... on success, filling *ptr with a valid memcg pointer. + * -ENOMEM ... charge failure because of resource limits. + * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup. + * + * Unlike the exported interface, an "oom" parameter is added. if oom==true, + * the oom-killer can be invoked. */ static int __mem_cgroup_try_charge(struct mm_struct *mm, gfp_t gfp_mask, @@ -2247,7 +2231,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, * set, if so charge the init_mm (happens for pagecache usage). */ if (!*ptr && !mm) - goto bypass; + *ptr = root_mem_cgroup; again: if (*ptr) { /* css should be a valid one */ memcg = *ptr; @@ -2273,7 +2257,9 @@ again: * task-struct. So, mm->owner can be NULL. */ memcg = mem_cgroup_from_task(p); - if (!memcg || mem_cgroup_is_root(memcg)) { + if (!memcg) + memcg = root_mem_cgroup; + if (mem_cgroup_is_root(memcg)) { rcu_read_unlock(); goto done; } @@ -2348,8 +2334,8 @@ nomem: *ptr = NULL; return -ENOMEM; bypass: - *ptr = NULL; - return 0; + *ptr = root_mem_cgroup; + return -EINTR; } /* @@ -2457,6 +2443,7 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), nr_pages); unlock_page_cgroup(pc); + WARN_ON_ONCE(PageLRU(page)); /* * "charge_statistics" updated event counter. Then, check it. * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. @@ -2468,7 +2455,7 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\ - (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION)) + (1 << PCG_MIGRATION)) /* * Because tail pages are not marked as "used", set it. We're under * zone->lru_lock, 'splitting on pmd' and compound_lock. @@ -2478,7 +2465,9 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, void mem_cgroup_split_huge_fixup(struct page *head) { struct page_cgroup *head_pc = lookup_page_cgroup(head); + struct mem_cgroup_per_zone *mz; struct page_cgroup *pc; + enum lru_list lru; int i; if (mem_cgroup_disabled()) @@ -2487,23 +2476,15 @@ void mem_cgroup_split_huge_fixup(struct page *head) pc = head_pc + i; pc->mem_cgroup = head_pc->mem_cgroup; smp_wmb();/* see __commit_charge() */ - /* - * LRU flags cannot be copied because we need to add tail - * page to LRU by generic call and our hooks will be called. - */ pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; } - - if (PageCgroupAcctLRU(head_pc)) { - enum lru_list lru; - struct mem_cgroup_per_zone *mz; - /* - * We hold lru_lock, then, reduce counter directly. - */ - lru = page_lru(head); - mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head); - MEM_CGROUP_ZSTAT(mz, lru) -= HPAGE_PMD_NR - 1; - } + /* + * Tail pages will be added to LRU. + * We hold lru_lock,then,reduce counter directly. + */ + lru = page_lru(head); + mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head); + MEM_CGROUP_ZSTAT(mz, lru) -= HPAGE_PMD_NR - 1; } #endif @@ -2620,7 +2601,7 @@ static int mem_cgroup_move_parent(struct page *page, parent = mem_cgroup_from_cont(pcg); ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false); - if (ret || !parent) + if (ret) goto put_back; if (nr_pages > 1) @@ -2667,9 +2648,8 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, pc = lookup_page_cgroup(page); ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom); - if (ret || !memcg) + if (ret == -ENOMEM) return ret; - __mem_cgroup_commit_charge(memcg, page, nr_pages, pc, ctype); return 0; } @@ -2736,10 +2716,9 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, if (!page_is_file_cache(page)) type = MEM_CGROUP_CHARGE_TYPE_SHMEM; - if (!PageSwapCache(page)) { + if (!PageSwapCache(page)) ret = mem_cgroup_charge_common(page, mm, gfp_mask, type); - WARN_ON_ONCE(PageLRU(page)); - } else { /* page is swapcache/shmem */ + else { /* page is swapcache/shmem */ ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg); if (!ret) __mem_cgroup_commit_charge_swapin(page, memcg, type); @@ -2781,11 +2760,16 @@ int mem_cgroup_try_charge_swapin(struct mm_struct *mm, *memcgp = memcg; ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true); css_put(&memcg->css); + if (ret == -EINTR) + ret = 0; return ret; charge_cur_mm: if (unlikely(!mm)) mm = &init_mm; - return __mem_cgroup_try_charge(mm, mask, 1, memcgp, true); + ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true); + if (ret == -EINTR) + ret = 0; + return ret; } static void @@ -3245,7 +3229,7 @@ int mem_cgroup_prepare_migration(struct page *page, *memcgp = memcg; ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, memcgp, false); css_put(&memcg->css);/* drop extra refcnt */ - if (ret || *memcgp == NULL) { + if (ret) { if (PageAnon(page)) { lock_page_cgroup(pc); ClearPageCgroupMigration(pc); @@ -3255,6 +3239,7 @@ int mem_cgroup_prepare_migration(struct page *page, */ mem_cgroup_uncharge_page(page); } + /* we'll need to revisit this error code (we have -EINTR) */ return -ENOMEM; } /* @@ -3674,7 +3659,7 @@ static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg, pc = lookup_page_cgroup(page); ret = mem_cgroup_move_parent(page, pc, memcg, GFP_KERNEL); - if (ret == -ENOMEM) + if (ret == -ENOMEM || ret == -EINTR) break; if (ret == -EBUSY || ret == -EINVAL) { @@ -5065,9 +5050,9 @@ one_by_one: } ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, 1, &memcg, false); - if (ret || !memcg) + if (ret) /* mem_cgroup_clear_mc() will do uncharge later */ - return -ENOMEM; + return ret; mc.precharge++; } return ret; |