From: Johannes Weiner <han...@cmpxchg.org> Some callsites pass a memcg directly, some callsites pass an mm that then has to be translated to a memcg. This makes for a terrible function interface.
Just push the mm-to-memcg translation into the respective callsites and always pass a memcg to mem_cgroup_try_charge(). [mho...@suse.cz: add charge mm helper] Signed-off-by: Johannes Weiner <han...@cmpxchg.org> Acked-by: Michal Hocko <mho...@suse.cz> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> https://jira.sw.ru/browse/PSBM-51558 (cherry picked from commit 6d1fdc48938cd51a3964778d78f27cb26c8eb55d) Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com> --- mm/memcontrol.c | 207 ++++++++++++++++++++++++++++---------------------------- 1 file changed, 102 insertions(+), 105 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d6413c5..1e5d914 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2745,7 +2745,7 @@ static int memcg_cpu_hotplug_callback(struct notifier_block *nb, } -/* See __mem_cgroup_try_charge() for details */ +/* See mem_cgroup_try_charge() for details */ enum { CHARGE_OK, /* success */ CHARGE_RETRY, /* need to retry but retry is not bad */ @@ -2824,45 +2824,35 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, return CHARGE_NOMEM; } -/* - * __mem_cgroup_try_charge() does - * 1. detect memcg to be charged against from passed *mm and *ptr, - * 2. update page_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. +/** + * mem_cgroup_try_charge - try charging a memcg + * @memcg: memcg to charge + * @nr_pages: number of pages to charge + * @oom: trigger OOM if reclaim fails * - * Unlike the exported interface, an "oom" parameter is added. if oom==true, - * the oom-killer can be invoked. + * Returns 0 if @memcg was charged successfully, -EINTR if the charge + * was bypassed to root_mem_cgroup, and -ENOMEM if the charge failed. */ -static int __mem_cgroup_try_charge(struct mm_struct *mm, - gfp_t gfp_mask, - unsigned int nr_pages, - struct mem_cgroup **ptr, - bool oom) +static int mem_cgroup_try_charge(struct mem_cgroup *memcg, + gfp_t gfp_mask, + unsigned int nr_pages, + bool oom) { unsigned int batch = max(CHARGE_BATCH, nr_pages); int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; - struct mem_cgroup *memcg = NULL, *iter; + struct mem_cgroup *iter; int ret; + if (mem_cgroup_is_root(memcg)) + goto done; /* - * Unlike gloval-vm's OOM-kill, we're not in memory shortage - * in system level. So, allow to go ahead dying process in addition to - * MEMDIE process. + * Unlike in global OOM situations, memcg is not in a physical + * memory shortage. Allow dying and OOM-killed tasks to + * bypass the last charges so that they can exit quickly and + * free their memory. */ - if (unlikely(test_thread_flag(TIF_MEMDIE) - || fatal_signal_pending(current))) + if (unlikely(test_thread_flag(TIF_MEMDIE) || + fatal_signal_pending(current))) goto bypass; if (unlikely(task_in_memcg_oom(current))) @@ -2871,14 +2861,6 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, if (gfp_mask & __GFP_NOFAIL) oom = false; again: - if (*ptr) { /* css should be a valid one */ - memcg = *ptr; - css_get(&memcg->css); - } else { - memcg = get_mem_cgroup_from_mm(mm); - } - if (mem_cgroup_is_root(memcg)) - goto done; if (consume_stock(memcg, nr_pages)) goto done; @@ -2887,10 +2869,8 @@ again: /* If killed, bypass charge */ if (test_thread_flag(TIF_MEMDIE) || - fatal_signal_pending(current)) { - css_put(&memcg->css); + fatal_signal_pending(current)) goto bypass; - } ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, nr_pages, invoke_oom); @@ -2899,17 +2879,12 @@ again: break; case CHARGE_RETRY: /* not in OOM situation but retry */ batch = nr_pages; - css_put(&memcg->css); - memcg = NULL; goto again; case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ - css_put(&memcg->css); goto nomem; case CHARGE_NOMEM: /* OOM routine works */ - if (!oom || invoke_oom) { - css_put(&memcg->css); + if (!oom || invoke_oom) goto nomem; - } nr_oom_retries--; break; } @@ -2949,19 +2924,43 @@ again: } while ((iter = parent_mem_cgroup(iter))); done: - css_put(&memcg->css); - *ptr = memcg; return 0; nomem: - if (!(gfp_mask & __GFP_NOFAIL)) { - *ptr = NULL; + if (!(gfp_mask & __GFP_NOFAIL)) return -ENOMEM; - } bypass: - *ptr = root_mem_cgroup; return -EINTR; } +/** + * mem_cgroup_try_charge_mm - try charging a mm + * @mm: mm_struct to charge + * @nr_pages: number of pages to charge + * @oom: trigger OOM if reclaim fails + * + * Returns the charged mem_cgroup associated with the given mm_struct or + * NULL the charge failed. + */ +static struct mem_cgroup *mem_cgroup_try_charge_mm(struct mm_struct *mm, + gfp_t gfp_mask, + unsigned int nr_pages, + bool oom) + +{ + struct mem_cgroup *memcg; + int ret; + + memcg = get_mem_cgroup_from_mm(mm); + ret = mem_cgroup_try_charge(memcg, gfp_mask, nr_pages, oom); + css_put(&memcg->css); + if (ret == -EINTR) + memcg = root_mem_cgroup; + else if (ret) + memcg = NULL; + + return memcg; +} + /* * Somemtimes we have to undo a charge we got by try_charge(). * This function is for that and do uncharge, put css's refcnt. @@ -3119,7 +3118,6 @@ int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, unsigned long nr_pages) { struct page_counter *counter; - struct mem_cgroup *_memcg; int ret = 0; bool may_oom; @@ -3129,13 +3127,10 @@ int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, */ may_oom = (gfp & __GFP_FS) && !(gfp & __GFP_NORETRY); - _memcg = memcg; - ret = __mem_cgroup_try_charge(NULL, gfp | __GFP_NOFAIL, - nr_pages, &_memcg, may_oom); - + ret = mem_cgroup_try_charge(memcg, gfp, nr_pages, may_oom); if (ret == -EINTR) { /* - * __mem_cgroup_try_charge() chosed to bypass to root due to + * mem_cgroup_try_charge() chosed to bypass to root due to * OOM kill or fatal signal. Since our only options are to * either fail the allocation or charge it to this cgroup, do * it as a temporary condition. But we can't fail. From a @@ -3145,7 +3140,7 @@ int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, * * This condition will only trigger if the task entered * memcg_charge_kmem in a sane state, but was OOM-killed during - * __mem_cgroup_try_charge() above. Tasks that were already + * mem_cgroup_try_charge() above. Tasks that were already * dying when the allocation triggers should have been already * directed to the root cgroup in memcontrol.h */ @@ -3764,10 +3759,9 @@ out: int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { - struct mem_cgroup *memcg = NULL; unsigned int nr_pages = 1; + struct mem_cgroup *memcg; bool oom = true; - int ret; if (mem_cgroup_disabled()) return 0; @@ -3786,9 +3780,9 @@ int mem_cgroup_newpage_charge(struct page *page, oom = false; } - ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom); - if (ret == -ENOMEM) - return ret; + memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, nr_pages, oom); + if (!memcg) + return -ENOMEM; __mem_cgroup_commit_charge(memcg, page, nr_pages, MEM_CGROUP_CHARGE_TYPE_ANON, false); return 0; @@ -3805,7 +3799,7 @@ static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm, gfp_t mask, struct mem_cgroup **memcgp) { - struct mem_cgroup *memcg; + struct mem_cgroup *memcg = NULL; struct page_cgroup *pc; int ret; @@ -3818,31 +3812,29 @@ static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm, * in turn serializes uncharging. */ if (PageCgroupUsed(pc)) - return 0; - if (!do_swap_account) - goto charge_cur_mm; - memcg = try_get_mem_cgroup_from_page(page); + goto out; + if (do_swap_account) + memcg = try_get_mem_cgroup_from_page(page); if (!memcg) - goto charge_cur_mm; - *memcgp = memcg; - ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true); + memcg = get_mem_cgroup_from_mm(mm); + ret = mem_cgroup_try_charge(memcg, mask, 1, true); css_put(&memcg->css); if (ret == -EINTR) - ret = 0; - return ret; -charge_cur_mm: - ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true); - if (ret == -EINTR) - ret = 0; - return ret; + memcg = root_mem_cgroup; + else if (ret) + return ret; +out: + *memcgp = memcg; + return 0; } int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page, gfp_t gfp_mask, struct mem_cgroup **memcgp) { - *memcgp = NULL; - if (mem_cgroup_disabled()) + if (mem_cgroup_disabled()) { + *memcgp = NULL; return 0; + } /* * A racing thread's fault, or swapoff, may have already * updated the pte, and even removed page from swap cache: in @@ -3850,12 +3842,13 @@ int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page, * there's also a KSM case which does need to charge the page. */ if (!PageSwapCache(page)) { - int ret; + struct mem_cgroup *memcg; - ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, memcgp, true); - if (ret == -EINTR) - ret = 0; - return ret; + memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true); + if (!memcg) + return -ENOMEM; + *memcgp = memcg; + return 0; } return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp); } @@ -3904,8 +3897,8 @@ void mem_cgroup_commit_charge_swapin(struct page *page, int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask) { - struct mem_cgroup *memcg = NULL; enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; + struct mem_cgroup *memcg; int ret; if (mem_cgroup_disabled()) @@ -3913,23 +3906,28 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, if (PageCompound(page)) return 0; - if (!PageSwapCache(page)) { - /* - * Page cache insertions can happen without an actual - * task context, e.g. during disk probing on boot. - */ - if (!mm) - memcg = root_mem_cgroup; - ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &memcg, true); - if (ret != -ENOMEM) - __mem_cgroup_commit_charge(memcg, page, 1, type, false); - } else { /* page is swapcache/shmem */ + if (PageSwapCache(page)) { /* shmem */ ret = __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg); - if (!ret) - __mem_cgroup_commit_charge_swapin(page, memcg, type); + if (ret) + return ret; + __mem_cgroup_commit_charge_swapin(page, memcg, type); + return 0; } - return ret; + + /* + * Page cache insertions can happen without an actual mm + * context, e.g. during disk probing on boot. + */ + if (unlikely(!mm)) + memcg = root_mem_cgroup; + else { + memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1, true); + if (!memcg) + return -ENOMEM; + } + __mem_cgroup_commit_charge(memcg, page, 1, type, false); + return 0; } static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg, @@ -6867,8 +6865,7 @@ one_by_one: batch_count = PRECHARGE_COUNT_AT_ONCE; cond_resched(); } - ret = __mem_cgroup_try_charge(NULL, - GFP_KERNEL, 1, &memcg, false); + ret = mem_cgroup_try_charge(memcg, GFP_KERNEL, 1, false); if (ret) /* mem_cgroup_clear_mc() will do uncharge later */ return ret; -- 2.10.2 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
