From patchwork Thu Feb 20 16:51:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 11394611 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 05F21159A for ; Thu, 20 Feb 2020 16:52:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5E05208E4 for ; Thu, 20 Feb 2020 16:52:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mRplJTIV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728354AbgBTQwg (ORCPT ); Thu, 20 Feb 2020 11:52:36 -0500 Received: from mail-qk1-f194.google.com ([209.85.222.194]:46726 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727709AbgBTQwg (ORCPT ); Thu, 20 Feb 2020 11:52:36 -0500 Received: by mail-qk1-f194.google.com with SMTP id u124so4154305qkh.13; Thu, 20 Feb 2020 08:52:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=FYNVHlKgDQ46X+XbR/60sAiRfHp1T0eWqZr2l7PitAY=; b=mRplJTIVJvwxpfcqw1dz1JBHO/xQGnQyFaChntDSc5MNme2JxeChi/bpTJQGi2EMq1 8cIt6V0A0cRKVgMt8j34VVrEuLKAhSrGC593vKSouczGi3i55noG8wUfiNagIdDdvKke rfj2cJeUjjLQzqTr1rzSvR26xwlJ+Lo1sIbrq9vrjXgJe/O2/dWT9tD+zy/YizOlT6Q7 y8AvtOXyJJyczYaAt+Hk5J7Oqhe2nHEFjUyWAXSTocGoGZCX5Sn1L2GTXx4W8MzYj16z H9jjzGwayvlZmXV6qrqv0EgVqVi8iacMxVH7XCeZAw/ZlTfwEvvv77h/VlQpYf06Oc4c Kfbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=FYNVHlKgDQ46X+XbR/60sAiRfHp1T0eWqZr2l7PitAY=; b=FZSxnQDF9HqL6VutBPP83+EG7q1VD9rm3rpkZ5KgQ+vADJ85hp/oWfW2H6d2ONkJkc xS0nkcvNFOztmFbMoKHDSFQaU7c+BLCNgAVFHhKUWlQHRowWooWSgmXyKHS1K1u+Pe+0 rQ5ErFZnLmCCzWBbxgkDfCi5mMlno0GtzQAIfsg8Ce7L0NSQde5fFOuzkObbjS1yP4DY SR8DugdK6tNeRBYN84PSmNw9Bk4hGgxYCBA2/xYGX37acqfOlakZ8eeeIc4xeF7C4y+L ZGrl/pGvvpX7tBzdyN2GDkNCJlfVVaKwoRM4p1TgMiL9LDOoWzOtBu1QOWQYiaNGPlZu Wt3g== X-Gm-Message-State: APjAAAXsEzZ2XkeyWbEWbvhotlC8u7eF9kIFUs4847ysFrHUtn9usBmI AC/cZxnMuK+JlHIZ01Y56DQ= X-Google-Smtp-Source: APXvYqzD9cWPQf5UM0f9Pf6Mkn/wkKPaIxfck7hrx6xRV/WzgwEsGJg0M8N/ODEy4+fT++tQp0ZHYQ== X-Received: by 2002:a37:e317:: with SMTP id y23mr28832696qki.431.1582217554540; Thu, 20 Feb 2020 08:52:34 -0800 (PST) Received: from dschatzberg-fedora-PC0Y6AEN.thefacebook.com ([2620:10d:c091:500::3:edb0]) by smtp.gmail.com with ESMTPSA id t55sm43567qte.24.2020.02.20.08.52.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2020 08:52:33 -0800 (PST) From: Dan Schatzberg Cc: Dan Schatzberg , Jens Axboe , Tejun Heo , Li Zefan , Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , Roman Gushchin , Shakeel Butt , Chris Down , Yang Shi , Thomas Gleixner , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)) Subject: [PATCH v3 1/3] loop: Use worker per cgroup instead of kworker Date: Thu, 20 Feb 2020 11:51:51 -0500 Message-Id: <118a1bd99d12f1980c7fc01ab732b40ffd8f0537.1582216294.git.schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.21.1 In-Reply-To: References: MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Existing uses of loop device may have multiple cgroups reading/writing to the same device. Simply charging resources for I/O to the backing file could result in priority inversion where one cgroup gets synchronously blocked, holding up all other I/O to the loop device. In order to avoid this priority inversion, we use a single workqueue where each work item is a "struct loop_worker" which contains a queue of struct loop_cmds to issue. The loop device maintains a tree mapping blk css_id -> loop_worker. This allows each cgroup to independently make forward progress issuing I/O to the backing file. There is also a single queue for I/O associated with the rootcg which can be used in cases of extreme memory shortage where we cannot allocate a loop_worker. The locking for the tree and queues is fairly heavy handed - we acquire the per-loop-device spinlock any time either is accessed. The existing implementation serializes all I/O through a single thread anyways, so I don't believe this is any worse. Signed-off-by: Dan Schatzberg Acked-by: Johannes Weiner --- drivers/block/loop.c | 188 +++++++++++++++++++++++++++++++++++++------ drivers/block/loop.h | 11 ++- 2 files changed, 170 insertions(+), 29 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 739b372a5112..78e5005c6742 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -70,7 +70,6 @@ #include #include #include -#include #include #include #include @@ -83,6 +82,8 @@ #include +#define LOOP_IDLE_WORKER_TIMEOUT (60 * HZ) + static DEFINE_IDR(loop_index_idr); static DEFINE_MUTEX(loop_ctl_mutex); @@ -891,27 +892,101 @@ static void loop_config_discard(struct loop_device *lo) static void loop_unprepare_queue(struct loop_device *lo) { - kthread_flush_worker(&lo->worker); - kthread_stop(lo->worker_task); -} - -static int loop_kthread_worker_fn(void *worker_ptr) -{ - current->flags |= PF_LESS_THROTTLE | PF_MEMALLOC_NOIO; - return kthread_worker_fn(worker_ptr); + destroy_workqueue(lo->workqueue); } static int loop_prepare_queue(struct loop_device *lo) { - kthread_init_worker(&lo->worker); - lo->worker_task = kthread_run(loop_kthread_worker_fn, - &lo->worker, "loop%d", lo->lo_number); - if (IS_ERR(lo->worker_task)) + lo->workqueue = alloc_workqueue("loop%d", + WQ_UNBOUND | WQ_FREEZABLE | + WQ_MEM_RECLAIM, + lo->lo_number); + if (IS_ERR(lo->workqueue)) return -ENOMEM; - set_user_nice(lo->worker_task, MIN_NICE); + return 0; } +struct loop_worker { + struct rb_node rb_node; + struct work_struct work; + struct list_head cmd_list; + struct list_head idle_list; + struct loop_device *lo; + struct cgroup_subsys_state *css; + unsigned long last_ran_at; +}; + +static void loop_workfn(struct work_struct *work); +static void loop_rootcg_workfn(struct work_struct *work); +static void loop_free_idle_workers(struct timer_list *timer); + +static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd) +{ + struct rb_node **node = &(lo->worker_tree.rb_node), *parent = NULL; + struct loop_worker *cur_worker, *worker = NULL; + struct work_struct *work; + struct list_head *cmd_list; + + spin_lock_irq(&lo->lo_lock); + + if (!cmd->css) + goto queue_work; + + node = &(lo->worker_tree.rb_node); + + while (*node) { + parent = *node; + cur_worker = container_of(*node, struct loop_worker, rb_node); + if ((long)cur_worker->css == (long)cmd->css) { + worker = cur_worker; + break; + } else if ((long)cur_worker->css < (long)cmd->css) { + node = &((*node)->rb_left); + } else { + node = &((*node)->rb_right); + } + } + if (worker) + goto queue_work; + + worker = kzalloc(sizeof(struct loop_worker), + GFP_NOWAIT | __GFP_NOWARN); + /* + * In the event we cannot allocate a worker, just queue on the + * rootcg worker + */ + if (!worker) + goto queue_work; + + worker->css = cmd->css; + css_get(worker->css); + INIT_WORK(&worker->work, loop_workfn); + INIT_LIST_HEAD(&worker->cmd_list); + INIT_LIST_HEAD(&worker->idle_list); + worker->lo = lo; + rb_link_node(&worker->rb_node, parent, node); + rb_insert_color(&worker->rb_node, &lo->worker_tree); +queue_work: + if (worker) { + /* + * We need to remove from the idle list here while + * holding the lock so that the idle timer doesn't + * free the worker + */ + if (!list_empty(&worker->idle_list)) + list_del_init(&worker->idle_list); + work = &worker->work; + cmd_list = &worker->cmd_list; + } else { + work = &lo->rootcg_work; + cmd_list = &lo->rootcg_cmd_list; + } + list_add_tail(&cmd->list_entry, cmd_list); + queue_work(lo->workqueue, work); + spin_unlock_irq(&lo->lo_lock); +} + static void loop_update_rotational(struct loop_device *lo) { struct file *file = lo->lo_backing_file; @@ -993,6 +1068,12 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0); + INIT_WORK(&lo->rootcg_work, loop_rootcg_workfn); + INIT_LIST_HEAD(&lo->rootcg_cmd_list); + INIT_LIST_HEAD(&lo->idle_worker_list); + lo->worker_tree = RB_ROOT; + timer_setup(&lo->timer, loop_free_idle_workers, + TIMER_DEFERRABLE); lo->use_dio = false; lo->lo_device = bdev; lo->lo_flags = lo_flags; @@ -1155,6 +1236,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release) partscan = lo->lo_flags & LO_FLAGS_PARTSCAN && bdev; lo_number = lo->lo_number; loop_unprepare_queue(lo); + del_timer_sync(&lo->timer); out_unlock: mutex_unlock(&loop_ctl_mutex); if (partscan) { @@ -1932,7 +2014,7 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, } else #endif cmd->css = NULL; - kthread_queue_work(&lo->worker, &cmd->work); + loop_queue_work(lo, cmd); return BLK_STS_OK; } @@ -1958,26 +2040,82 @@ static void loop_handle_cmd(struct loop_cmd *cmd) } } -static void loop_queue_work(struct kthread_work *work) +static void loop_set_timer(struct loop_device *lo) { - struct loop_cmd *cmd = - container_of(work, struct loop_cmd, work); + timer_reduce(&lo->timer, jiffies + LOOP_IDLE_WORKER_TIMEOUT); +} + +static void loop_process_work(struct loop_worker *worker, + struct list_head *cmd_list, struct loop_device *lo) +{ + int orig_flags = current->flags; + struct loop_cmd *cmd; + + current->flags |= PF_LESS_THROTTLE | PF_MEMALLOC_NOIO; + while (1) { + spin_lock_irq(&lo->lo_lock); + if (list_empty(cmd_list)) + break; + + cmd = container_of( + cmd_list->next, struct loop_cmd, list_entry); + list_del(cmd_list->next); + spin_unlock_irq(&lo->lo_lock); + loop_handle_cmd(cmd); + cond_resched(); + } - loop_handle_cmd(cmd); + /* + * We only add to the idle list if there are no pending cmds + * *and* the worker will not run again which ensures that it + * is safe to free any worker on the idle list + */ + if (worker && !work_pending(&worker->work)) { + worker->last_ran_at = jiffies; + list_add_tail(&worker->idle_list, &lo->idle_worker_list); + loop_set_timer(lo); + } + spin_unlock_irq(&lo->lo_lock); + current->flags = orig_flags; } -static int loop_init_request(struct blk_mq_tag_set *set, struct request *rq, - unsigned int hctx_idx, unsigned int numa_node) +static void loop_workfn(struct work_struct *work) { - struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); + struct loop_worker *worker = + container_of(work, struct loop_worker, work); + loop_process_work(worker, &worker->cmd_list, worker->lo); +} - kthread_init_work(&cmd->work, loop_queue_work); - return 0; +static void loop_rootcg_workfn(struct work_struct *work) +{ + struct loop_device *lo = + container_of(work, struct loop_device, rootcg_work); + loop_process_work(NULL, &lo->rootcg_cmd_list, lo); +} + +static void loop_free_idle_workers(struct timer_list *timer) +{ + struct loop_device *lo = container_of(timer, struct loop_device, timer); + struct loop_worker *pos, *worker; + + spin_lock_irq(&lo->lo_lock); + list_for_each_entry_safe(worker, pos, &lo->idle_worker_list, + idle_list) { + if (time_is_after_jiffies(worker->last_ran_at + + LOOP_IDLE_WORKER_TIMEOUT)) + break; + list_del(&worker->idle_list); + rb_erase(&worker->rb_node, &lo->worker_tree); + css_put(worker->css); + kfree(worker); + } + if (!list_empty(&lo->idle_worker_list)) + loop_set_timer(lo); + spin_unlock_irq(&lo->lo_lock); } static const struct blk_mq_ops loop_mq_ops = { .queue_rq = loop_queue_rq, - .init_request = loop_init_request, .complete = lo_complete_rq, }; diff --git a/drivers/block/loop.h b/drivers/block/loop.h index af75a5ee4094..87fd0e372227 100644 --- a/drivers/block/loop.h +++ b/drivers/block/loop.h @@ -14,7 +14,6 @@ #include #include #include -#include #include /* Possible states of device */ @@ -54,8 +53,12 @@ struct loop_device { spinlock_t lo_lock; int lo_state; - struct kthread_worker worker; - struct task_struct *worker_task; + struct workqueue_struct *workqueue; + struct work_struct rootcg_work; + struct list_head rootcg_cmd_list; + struct list_head idle_worker_list; + struct rb_root worker_tree; + struct timer_list timer; bool use_dio; bool sysfs_inited; @@ -65,7 +68,7 @@ struct loop_device { }; struct loop_cmd { - struct kthread_work work; + struct list_head list_entry; bool use_aio; /* use AIO interface to handle I/O */ atomic_t ref; /* only for aio */ long ret; From patchwork Thu Feb 20 16:51:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 11394613 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 21966159A for ; Thu, 20 Feb 2020 16:52:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0106224676 for ; 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Thu, 20 Feb 2020 08:52:38 -0800 (PST) From: Dan Schatzberg Cc: Dan Schatzberg , Jens Axboe , Tejun Heo , Li Zefan , Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , Roman Gushchin , Shakeel Butt , Chris Down , Yang Shi , Thomas Gleixner , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)) Subject: [PATCH v3 2/3] mm: Charge active memcg when no mm is set Date: Thu, 20 Feb 2020 11:51:52 -0500 Message-Id: <0a27b6fcbd1f7af104d7f4cf0adc6a31e0e7dd19.1582216294.git.schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.21.1 In-Reply-To: References: MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org memalloc_use_memcg() worked for kernel allocations but was silently ignored for user pages. This patch establishes a precedence order for who gets charged: 1. If there is a memcg associated with the page already, that memcg is charged. This happens during swapin. 2. If an explicit mm is passed, mm->memcg is charged. This happens during page faults, which can be triggered in remote VMs (eg gup). 3. Otherwise consult the current process context. If it has configured a current->active_memcg, use that. Otherwise, current->mm->memcg. Previously, if a NULL mm was passed to mem_cgroup_try_charge (case 3) it would always charge the root cgroup. Now it looks up the current active_memcg first (falling back to charging the root cgroup if not set). Signed-off-by: Dan Schatzberg Acked-by: Johannes Weiner Acked-by: Tejun Heo Acked-by: Chris Down Reviewed-by: Shakeel Butt Acked-by: Hugh Dickins --- mm/memcontrol.c | 11 ++++++++--- mm/shmem.c | 2 +- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6f6dc8712e39..b174aff4f069 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6317,7 +6317,8 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, * @compound: charge the page as compound or small page * * Try to charge @page to the memcg that @mm belongs to, reclaiming - * pages according to @gfp_mask if necessary. + * pages according to @gfp_mask if necessary. If @mm is NULL, try to + * charge to the active memcg. * * Returns 0 on success, with *@memcgp pointing to the charged memcg. * Otherwise, an error code is returned. @@ -6361,8 +6362,12 @@ int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, } } - if (!memcg) - memcg = get_mem_cgroup_from_mm(mm); + if (!memcg) { + if (!mm) + memcg = get_mem_cgroup_from_current(); + else + memcg = get_mem_cgroup_from_mm(mm); + } ret = try_charge(memcg, gfp_mask, nr_pages); diff --git a/mm/shmem.c b/mm/shmem.c index c8f7540ef048..7c7f5acf89d6 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1766,7 +1766,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, } sbinfo = SHMEM_SB(inode->i_sb); - charge_mm = vma ? vma->vm_mm : current->mm; + charge_mm = vma ? vma->vm_mm : NULL; page = find_lock_entry(mapping, index); if (xa_is_value(page)) { From patchwork Thu Feb 20 16:51:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 11394619 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 27AC217F0 for ; Thu, 20 Feb 2020 16:52:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E923724672 for ; Thu, 20 Feb 2020 16:52:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ounh9xWS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728655AbgBTQwp (ORCPT ); Thu, 20 Feb 2020 11:52:45 -0500 Received: from mail-qt1-f193.google.com ([209.85.160.193]:37750 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727709AbgBTQwo (ORCPT ); Thu, 20 Feb 2020 11:52:44 -0500 Received: by mail-qt1-f193.google.com with SMTP id w47so3343196qtk.4; Thu, 20 Feb 2020 08:52:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=HFqJ14YKY+5wy3KCvZ+515HEc/MVkRiy5DoJCFVvdM4=; b=ounh9xWSSx7BkWdsIV7CUBQbJ3a9Lg44mK+wLrArRT1iZjJcWysvsqbKEJMH64eLWQ EYCWwBvoIx+I67W8yDM38s66MmDgzvuFur4v2Xnp51FRfZXONqQp5PuzIk/Y0tKRUT6Z //wAa49WHf2IRfdxjW/dyDbhiSSJuLK6QKAnawcTEnIB+uIczylEFdmC05EoYhCvB983 h/wpOxBdYm15yALIdACfemBPlnIPPaSS6jYtpSuUDVonvTbQtL63FK6obk6a7s60vh2+ zKtlq8fV+J4bAGdJZB27jtxJbV3egGZPSSsf4ppgKNy4kxNgY81ITftVX2l+H454QXpd FYsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=HFqJ14YKY+5wy3KCvZ+515HEc/MVkRiy5DoJCFVvdM4=; b=hepV1ZEpJQ/MyHld3zyPZu0saq7vD5VZXgJITEf7n88ohhPKxJ/R18dYG9uP6M9YMa PygVbhYlhyB61TntKPBaWwomx/GBu/WVtrCXr+zmPtzNBr5YZUC8n9q2sWunEtGrqaoL 800yw6XI9YOyhg5R+QhPCMbUiokR//AT1G01MxCCrqowJWJvDFiKSN1Au3pv6pKSTGJg Y/R3UsXi94OF+TlW/nO7Nsxju6TdKaphEBtK1Jpyvlged/zIt4Yfj+t1kXQwOjLF3560 A4XJ0uBdFAJnAVi2j5+aqu4T0iuTWh5G2bM2/q6YoCdKW0V0koD9LDzEsnnN86NMfalk 4i3g== X-Gm-Message-State: APjAAAX8qDBKZaZ1jNLB5WDAS1x7dD0vdy8a6j/8YzSYBFth3bLAPXJY KPjyCywx61HErbpnIBi7enk= X-Google-Smtp-Source: APXvYqySmGLf8naIjHM7lRSfnO3lL50yvtDB/fzEXPc6UkiyNWC0qCVyKSnBLYOg/Xwkb1XOvYVLXA== X-Received: by 2002:ac8:4a02:: with SMTP id x2mr27604183qtq.388.1582217563077; Thu, 20 Feb 2020 08:52:43 -0800 (PST) Received: from dschatzberg-fedora-PC0Y6AEN.thefacebook.com ([2620:10d:c091:500::3:edb0]) by smtp.gmail.com with ESMTPSA id t55sm43567qte.24.2020.02.20.08.52.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2020 08:52:42 -0800 (PST) From: Dan Schatzberg Cc: Dan Schatzberg , Jens Axboe , Tejun Heo , Li Zefan , Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , Roman Gushchin , Shakeel Butt , Chris Down , Yang Shi , Thomas Gleixner , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)) Subject: [PATCH v3 3/3] loop: Charge i/o to mem and blk cg Date: Thu, 20 Feb 2020 11:51:53 -0500 Message-Id: <78060dcbf6578b4da6081f9f48b24b33726c5083.1582216295.git.schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.21.1 In-Reply-To: References: MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org The current code only associates with the existing blkcg when aio is used to access the backing file. This patch covers all types of i/o to the backing file and also associates the memcg so if the backing file is on tmpfs, memory is charged appropriately. This patch also exports cgroup_get_e_css so it can be used by the loop module. Signed-off-by: Dan Schatzberg Acked-by: Johannes Weiner --- drivers/block/loop.c | 59 ++++++++++++++++++++++++-------------- drivers/block/loop.h | 3 +- include/linux/memcontrol.h | 6 ++++ kernel/cgroup/cgroup.c | 1 + 4 files changed, 47 insertions(+), 22 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 78e5005c6742..cc091a66b0d0 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -77,6 +77,7 @@ #include #include #include +#include #include "loop.h" @@ -134,7 +135,7 @@ static struct loop_func_table xor_funcs = { .number = LO_CRYPT_XOR, .transfer = transfer_xor, .init = xor_init -}; +}; /* xfer_funcs[0] is special - its release function is never called */ static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = { @@ -504,8 +505,6 @@ static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2) { struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb); - if (cmd->css) - css_put(cmd->css); cmd->ret = ret; lo_rw_aio_do_completion(cmd); } @@ -566,8 +565,6 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, cmd->iocb.ki_complete = lo_rw_aio_complete; cmd->iocb.ki_flags = IOCB_DIRECT; cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); - if (cmd->css) - kthread_associate_blkcg(cmd->css); if (rw == WRITE) ret = call_write_iter(file, &cmd->iocb, &iter); @@ -575,7 +572,6 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, ret = call_read_iter(file, &cmd->iocb, &iter); lo_rw_aio_do_completion(cmd); - kthread_associate_blkcg(NULL); if (ret != -EIOCBQUEUED) cmd->iocb.ki_complete(&cmd->iocb, ret, 0); @@ -913,7 +909,7 @@ struct loop_worker { struct list_head cmd_list; struct list_head idle_list; struct loop_device *lo; - struct cgroup_subsys_state *css; + struct cgroup_subsys_state *blkcg_css; unsigned long last_ran_at; }; @@ -930,7 +926,7 @@ static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd) spin_lock_irq(&lo->lo_lock); - if (!cmd->css) + if (!cmd->blkcg_css) goto queue_work; node = &(lo->worker_tree.rb_node); @@ -938,10 +934,10 @@ static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd) while (*node) { parent = *node; cur_worker = container_of(*node, struct loop_worker, rb_node); - if ((long)cur_worker->css == (long)cmd->css) { + if ((long)cur_worker->blkcg_css == (long)cmd->blkcg_css) { worker = cur_worker; break; - } else if ((long)cur_worker->css < (long)cmd->css) { + } else if ((long)cur_worker->blkcg_css < (long)cmd->blkcg_css) { node = &((*node)->rb_left); } else { node = &((*node)->rb_right); @@ -954,13 +950,16 @@ static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd) GFP_NOWAIT | __GFP_NOWARN); /* * In the event we cannot allocate a worker, just queue on the - * rootcg worker + * rootcg worker and issue the I/O as the rootcg */ - if (!worker) + if (!worker) { + cmd->blkcg_css = NULL; + cmd->memcg_css = NULL; goto queue_work; + } - worker->css = cmd->css; - css_get(worker->css); + worker->blkcg_css = cmd->blkcg_css; + css_get(worker->blkcg_css); INIT_WORK(&worker->work, loop_workfn); INIT_LIST_HEAD(&worker->cmd_list); INIT_LIST_HEAD(&worker->idle_list); @@ -2007,13 +2006,18 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx, } /* always use the first bio's css */ + cmd->blkcg_css = NULL; + cmd->memcg_css = NULL; #ifdef CONFIG_BLK_CGROUP - if (cmd->use_aio && rq->bio && rq->bio->bi_blkg) { - cmd->css = &bio_blkcg(rq->bio)->css; - css_get(cmd->css); - } else + if (rq->bio && rq->bio->bi_blkg) { + cmd->blkcg_css = &bio_blkcg(rq->bio)->css; +#ifdef CONFIG_MEMCG + cmd->memcg_css = + cgroup_get_e_css(cmd->blkcg_css->cgroup, + &memory_cgrp_subsys); +#endif + } #endif - cmd->css = NULL; loop_queue_work(lo, cmd); return BLK_STS_OK; @@ -2031,8 +2035,21 @@ static void loop_handle_cmd(struct loop_cmd *cmd) goto failed; } + if (cmd->blkcg_css) + kthread_associate_blkcg(cmd->blkcg_css); + if (cmd->memcg_css) + memalloc_use_memcg(mem_cgroup_from_css(cmd->memcg_css)); + ret = do_req_filebacked(lo, rq); - failed: + + if (cmd->blkcg_css) + kthread_associate_blkcg(NULL); + + if (cmd->memcg_css) { + memalloc_unuse_memcg(); + css_put(cmd->memcg_css); + } +failed: /* complete non-aio request */ if (!cmd->use_aio || ret) { cmd->ret = ret ? -EIO : 0; @@ -2106,7 +2123,7 @@ static void loop_free_idle_workers(struct timer_list *timer) break; list_del(&worker->idle_list); rb_erase(&worker->rb_node, &lo->worker_tree); - css_put(worker->css); + css_put(worker->blkcg_css); kfree(worker); } if (!list_empty(&lo->idle_worker_list)) diff --git a/drivers/block/loop.h b/drivers/block/loop.h index 87fd0e372227..3e65acf7a0e9 100644 --- a/drivers/block/loop.h +++ b/drivers/block/loop.h @@ -74,7 +74,8 @@ struct loop_cmd { long ret; struct kiocb iocb; struct bio_vec *bvec; - struct cgroup_subsys_state *css; + struct cgroup_subsys_state *blkcg_css; + struct cgroup_subsys_state *memcg_css; }; /* Support for loadable transfer modules */ diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index a7a0a1a5c8d5..aeb51f2ded46 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -922,6 +922,12 @@ static inline struct mem_cgroup *get_mem_cgroup_from_page(struct page *page) return NULL; } +static inline +struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css) +{ + return NULL; +} + static inline void mem_cgroup_put(struct mem_cgroup *memcg) { } diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 75f687301bbf..c3896c2e0942 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -587,6 +587,7 @@ struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgrp, rcu_read_unlock(); return css; } +EXPORT_SYMBOL_GPL(cgroup_get_e_css); static void cgroup_get_live(struct cgroup *cgrp) {