From patchwork Thu May 28 13:54:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 11575887 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 9FD88913 for ; Thu, 28 May 2020 13:55:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7DF9720814 for ; Thu, 28 May 2020 13:55:21 +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="F1XzO78w" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390696AbgE1NzU (ORCPT ); Thu, 28 May 2020 09:55:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390552AbgE1NzQ (ORCPT ); Thu, 28 May 2020 09:55:16 -0400 Received: from mail-qt1-x842.google.com (mail-qt1-x842.google.com [IPv6:2607:f8b0:4864:20::842]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42E15C05BD1E; Thu, 28 May 2020 06:55:16 -0700 (PDT) Received: by mail-qt1-x842.google.com with SMTP id x12so57755qts.9; Thu, 28 May 2020 06:55:16 -0700 (PDT) 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=do00u1EViwq2XOXiBJYKJQNJlHGBTm6FM9ybOftUjSE=; b=F1XzO78wi9T6s3aGaks+zNCcf3vEaWPnG2rzMmIFUAHZ75eTY2UdOS5xYkj43RfbLH LJqgfimX9HK6PfEOLCwz78YXnOYE+b0ODXeaVOXgLf20yPaagJN7hathIb1IuhCJ2RG4 6IcitHPuB8dyp660Y/t2KHrSvWoA3gIXQ8cdFM/6dN9l1r6pK34lHrUgR5+jw80Arp23 MtEKFLDWQw70bzqwfHD98TNsjN01mYuV5nYCtggdAcU03DqjnXtOtnHxcKJb4Q23hRxr 0auJu/7IChx9yxHOCHpB2VAGakUipcz+YAul9OSspC8i2ljOZ2I57PIHw466n2rd36UB TH5g== 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=do00u1EViwq2XOXiBJYKJQNJlHGBTm6FM9ybOftUjSE=; b=nzaiui4DqUE9iMVEvBoSSnvW9DlvllBxHRNm45ejPyUYFLDZIsv5xzcnW7+aoNcCJ0 E3C2vJ1k4AXZ1nlmo7vwJH4xfwUatzaDVD+sYAKjyEa2LnUUhDU6ujluNfCYMQfBdSsK q51/KJIcUm+n4HFs2hXUzFO3tNGv63pqPSvOK5TLWjUSbxuKJh56Zp/QuU10BbAHL17s r64ePEAM6Hj7ak7EQruXX0J7Q5ivT4wGzqhVd8RziKsc4BgS3St3DPr2nCRUDrO7GTiu QZ+MpO1YObH/7vL9oD3+6YMI3qI7QxLIqdzlurmHPOqEWatv/opYy6ojAbxburnpeoRP 8Q+g== X-Gm-Message-State: AOAM530o263m8l7t0xKJhz8WlUwLEcpTwSyLdlHGpaX2I1UTaxPitKe6 5P3RU+lYno0kn6VPn2P7nCA= X-Google-Smtp-Source: ABdhPJzTBmmszKaET15RhhOdwZGmeZaWNiSnz/LYKCGXhWiFjlK3D6AxHKJN7F49w1Sm6SqI5hzpBA== X-Received: by 2002:aed:3beb:: with SMTP id s40mr2824236qte.322.1590674115310; Thu, 28 May 2020 06:55:15 -0700 (PDT) Received: from dschatzberg-fedora-PC0Y6AEN.thefacebook.com ([2620:10d:c091:480::1:1cb7]) by smtp.gmail.com with ESMTPSA id l186sm4890889qkf.89.2020.05.28.06.55.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 May 2020 06:55:14 -0700 (PDT) From: Dan Schatzberg Cc: Dan Schatzberg , Jens Axboe , Alexander Viro , Jan Kara , Amir Goldstein , Tejun Heo , Li Zefan , Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , Roman Gushchin , Shakeel Butt , Chris Down , Yang Shi , Thomas Gleixner , Ingo Molnar , "Peter Zijlstra (Intel)" , Mathieu Desnoyers , Andrea Arcangeli , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)) Subject: [PATCH 1/4] loop: Use worker per cgroup instead of kworker Date: Thu, 28 May 2020 09:54:36 -0400 Message-Id: <20200528135444.11508-2-schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200528135444.11508-1-schatzberg.dan@gmail.com> References: <20200528135444.11508-1-schatzberg.dan@gmail.com> 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 a 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 --- drivers/block/loop.c | 203 ++++++++++++++++++++++++++++++++++++------- drivers/block/loop.h | 12 ++- 2 files changed, 178 insertions(+), 37 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index da693e6a834e..378a68e5ccf3 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); @@ -911,27 +912,83 @@ static void loop_config_discard(struct loop_device *lo) blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q); } -static void loop_unprepare_queue(struct loop_device *lo) -{ - kthread_flush_worker(&lo->worker); - kthread_stop(lo->worker_task); -} +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 int loop_kthread_worker_fn(void *worker_ptr) -{ - current->flags |= PF_LESS_THROTTLE | PF_MEMALLOC_NOIO; - return kthread_worker_fn(worker_ptr); -} +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 int loop_prepare_queue(struct loop_device *lo) +static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd) { - 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)) - return -ENOMEM; - set_user_nice(lo->worker_task, MIN_NICE); - return 0; + 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_work_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 (cur_worker->css == 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_work_lock); } static void loop_update_rotational(struct loop_device *lo) @@ -1007,14 +1064,25 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, size = get_loop_size(lo, file); if ((loff_t)(sector_t)size != size) goto out_unlock; - error = loop_prepare_queue(lo); - if (error) + lo->workqueue = alloc_workqueue("loop%d", + WQ_UNBOUND | WQ_FREEZABLE | + WQ_MEM_RECLAIM, + lo->lo_number); + if (!lo->workqueue) { + error = -ENOMEM; goto out_unlock; + } error = 0; 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; @@ -1123,6 +1191,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release) int err = 0; bool partscan = false; int lo_number; + struct loop_worker *pos, *worker; mutex_lock(&loop_ctl_mutex); if (WARN_ON_ONCE(lo->lo_state != Lo_rundown)) { @@ -1139,6 +1208,18 @@ static int __loop_clr_fd(struct loop_device *lo, bool release) /* freeze request queue during the transition */ blk_mq_freeze_queue(lo->lo_queue); + destroy_workqueue(lo->workqueue); + spin_lock_irq(&lo->lo_work_lock); + list_for_each_entry_safe(worker, pos, &lo->idle_worker_list, + idle_list) { + list_del(&worker->idle_list); + rb_erase(&worker->rb_node, &lo->worker_tree); + css_put(worker->css); + kfree(worker); + } + spin_unlock_irq(&lo->lo_work_lock); + del_timer_sync(&lo->timer); + spin_lock_irq(&lo->lo_lock); lo->lo_backing_file = NULL; spin_unlock_irq(&lo->lo_lock); @@ -1176,7 +1257,6 @@ 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); out_unlock: mutex_unlock(&loop_ctl_mutex); if (partscan) { @@ -1954,7 +2034,7 @@ 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; } @@ -1983,26 +2063,82 @@ 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) +{ + 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; + spin_lock_irq(&lo->lo_work_lock); + while (!list_empty(cmd_list)) { + cmd = container_of( + cmd_list->next, struct loop_cmd, list_entry); + list_del(cmd_list->next); + spin_unlock_irq(&lo->lo_work_lock); + + loop_handle_cmd(cmd); + cond_resched(); + + spin_lock_irq(&lo->lo_work_lock); + } + + /* + * 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_work_lock); + current->flags = orig_flags; +} + +static void loop_workfn(struct work_struct *work) { - struct loop_cmd *cmd = - container_of(work, struct loop_cmd, work); + struct loop_worker *worker = + container_of(work, struct loop_worker, work); + loop_process_work(worker, &worker->cmd_list, worker->lo); +} - loop_handle_cmd(cmd); +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 int loop_init_request(struct blk_mq_tag_set *set, struct request *rq, - unsigned int hctx_idx, unsigned int numa_node) +static void loop_free_idle_workers(struct timer_list *timer) { - struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); + struct loop_device *lo = container_of(timer, struct loop_device, timer); + struct loop_worker *pos, *worker; - kthread_init_work(&cmd->work, loop_queue_work); - return 0; + spin_lock_irq(&lo->lo_work_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_work_lock); } static const struct blk_mq_ops loop_mq_ops = { .queue_rq = loop_queue_rq, - .init_request = loop_init_request, .complete = lo_complete_rq, }; @@ -2090,6 +2226,7 @@ static int loop_add(struct loop_device **l, int i) atomic_set(&lo->lo_refcnt, 0); lo->lo_number = i; spin_lock_init(&lo->lo_lock); + spin_lock_init(&lo->lo_work_lock); disk->major = LOOP_MAJOR; disk->first_minor = i << part_shift; disk->fops = &lo_fops; diff --git a/drivers/block/loop.h b/drivers/block/loop.h index af75a5ee4094..0162b55a68e1 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 +53,13 @@ struct loop_device { spinlock_t lo_lock; int lo_state; - struct kthread_worker worker; - struct task_struct *worker_task; + spinlock_t lo_work_lock; + 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 +69,7 @@ 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 May 28 13:54:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 11575893 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 465FE13B4 for ; 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Thu, 28 May 2020 06:55:21 -0700 (PDT) Received: from dschatzberg-fedora-PC0Y6AEN.thefacebook.com ([2620:10d:c091:480::1:1cb7]) by smtp.gmail.com with ESMTPSA id l186sm4890889qkf.89.2020.05.28.06.55.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 May 2020 06:55:20 -0700 (PDT) From: Dan Schatzberg Cc: Johannes Weiner , Shakeel Butt , Roman Gushchin , Naresh Kamboju , Jens Axboe , Alexander Viro , Jan Kara , Amir Goldstein , Tejun Heo , Li Zefan , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , Chris Down , Yafang Shao , Yang Shi , Thomas Gleixner , "Peter Zijlstra (Intel)" , Ingo Molnar , Mathieu Desnoyers , "Kirill A. Shutemov" , Andrea Arcangeli , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)) Subject: [PATCH 2/4] mm: support nesting memalloc_use_memcg() Date: Thu, 28 May 2020 09:54:37 -0400 Message-Id: <20200528135444.11508-3-schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200528135444.11508-1-schatzberg.dan@gmail.com> References: <20200528135444.11508-1-schatzberg.dan@gmail.com> 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 From: Johannes Weiner The memalloc_use_memcg() function to override the default memcg accounting context currently doesn't nest. But the patches to make the loop driver cgroup-aware will end up nesting: [ 98.137605] alloc_page_buffers+0x210/0x288 [ 98.141799] __getblk_gfp+0x1d4/0x400 [ 98.145475] ext4_read_block_bitmap_nowait+0x148/0xbc8 [ 98.150628] ext4_mb_init_cache+0x25c/0x9b0 [ 98.154821] ext4_mb_init_group+0x270/0x390 [ 98.159014] ext4_mb_good_group+0x264/0x270 [ 98.163208] ext4_mb_regular_allocator+0x480/0x798 [ 98.168011] ext4_mb_new_blocks+0x958/0x10f8 [ 98.172294] ext4_ext_map_blocks+0xec8/0x1618 [ 98.176660] ext4_map_blocks+0x1b8/0x8a0 [ 98.180592] ext4_writepages+0x830/0xf10 [ 98.184523] do_writepages+0xb4/0x198 [ 98.188195] __filemap_fdatawrite_range+0x170/0x1c8 [ 98.193086] filemap_write_and_wait_range+0x40/0xb0 [ 98.197974] ext4_punch_hole+0x4a4/0x660 [ 98.201907] ext4_fallocate+0x294/0x1190 [ 98.205839] loop_process_work+0x690/0x1100 [ 98.210032] loop_workfn+0x2c/0x110 [ 98.213529] process_one_work+0x3e0/0x648 [ 98.217546] worker_thread+0x70/0x670 [ 98.221217] kthread+0x1b8/0x1c0 [ 98.224452] ret_from_fork+0x10/0x18 where loop_process_work() sets the memcg override to the memcg that submitted the IO request, and alloc_page_buffers() sets the override to the memcg that instantiated the cache page, which may differ. Make memalloc_use_memcg() return the old memcg and convert existing users to a stacking model. Delete the unused memalloc_unuse_memcg(). Signed-off-by: Johannes Weiner Reviewed-by: Shakeel Butt Acked-by: Roman Gushchin Reported-by: Naresh Kamboju --- fs/buffer.c | 6 +++--- fs/notify/fanotify/fanotify.c | 5 +++-- fs/notify/inotify/inotify_fsnotify.c | 5 +++-- include/linux/sched/mm.h | 28 +++++++++------------------- 4 files changed, 18 insertions(+), 26 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index a60f60396cfa..585416dec6a2 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -851,13 +851,13 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, struct buffer_head *bh, *head; gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT; long offset; - struct mem_cgroup *memcg; + struct mem_cgroup *memcg, *old_memcg; if (retry) gfp |= __GFP_NOFAIL; memcg = get_mem_cgroup_from_page(page); - memalloc_use_memcg(memcg); + old_memcg = memalloc_use_memcg(memcg); head = NULL; offset = PAGE_SIZE; @@ -876,7 +876,7 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, set_bh_page(bh, page, offset); } out: - memalloc_unuse_memcg(); + memalloc_use_memcg(old_memcg); mem_cgroup_put(memcg); return head; /* diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 5435a40f82be..6b869d95bfb6 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -353,6 +353,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, gfp_t gfp = GFP_KERNEL_ACCOUNT; struct inode *id = fanotify_fid_inode(inode, mask, data, data_type); const struct path *path = fsnotify_data_path(data, data_type); + struct mem_cgroup *old_memcg; /* * For queues with unlimited length lost events are not expected and @@ -366,7 +367,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, gfp |= __GFP_RETRY_MAYFAIL; /* Whoever is interested in the event, pays for the allocation. */ - memalloc_use_memcg(group->memcg); + old_memcg = memalloc_use_memcg(group->memcg); if (fanotify_is_perm_event(mask)) { struct fanotify_perm_event *pevent; @@ -451,7 +452,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, } } out: - memalloc_unuse_memcg(); + memalloc_use_memcg(old_memcg); return event; } diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index 2ebc89047153..52f38e6e81b7 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -69,6 +69,7 @@ int inotify_handle_event(struct fsnotify_group *group, int ret; int len = 0; int alloc_len = sizeof(struct inotify_event_info); + struct mem_cgroup *old_memcg; if (WARN_ON(fsnotify_iter_vfsmount_mark(iter_info))) return 0; @@ -93,9 +94,9 @@ int inotify_handle_event(struct fsnotify_group *group, * trigger OOM killer in the target monitoring memcg as it may have * security repercussion. */ - memalloc_use_memcg(group->memcg); + old_memcg = memalloc_use_memcg(group->memcg); event = kmalloc(alloc_len, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL); - memalloc_unuse_memcg(); + memalloc_use_memcg(old_memcg); if (unlikely(!event)) { /* diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index c49257a3b510..95e8bfb0cab1 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -316,31 +316,21 @@ static inline void memalloc_nocma_restore(unsigned int flags) * __GFP_ACCOUNT allocations till the end of the scope will be charged to the * given memcg. * - * NOTE: This function is not nesting safe. + * NOTE: This function can nest. Users must save the return value and + * reset the previous value after their own charging scope is over */ -static inline void memalloc_use_memcg(struct mem_cgroup *memcg) +static inline struct mem_cgroup * +memalloc_use_memcg(struct mem_cgroup *memcg) { - WARN_ON_ONCE(current->active_memcg); + struct mem_cgroup *old = current->active_memcg; current->active_memcg = memcg; -} - -/** - * memalloc_unuse_memcg - Ends the remote memcg charging scope. - * - * This function marks the end of the remote memcg charging scope started by - * memalloc_use_memcg(). - */ -static inline void memalloc_unuse_memcg(void) -{ - current->active_memcg = NULL; + return old; } #else -static inline void memalloc_use_memcg(struct mem_cgroup *memcg) -{ -} - -static inline void memalloc_unuse_memcg(void) +static inline struct mem_cgroup * +memalloc_use_memcg(struct mem_cgroup *memcg) { + return NULL; } #endif From patchwork Thu May 28 13:54:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 11575899 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 48AF6913 for ; 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Thu, 28 May 2020 06:55:27 -0700 (PDT) Received: from dschatzberg-fedora-PC0Y6AEN.thefacebook.com ([2620:10d:c091:480::1:1cb7]) by smtp.gmail.com with ESMTPSA id l186sm4890889qkf.89.2020.05.28.06.55.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 May 2020 06:55:26 -0700 (PDT) From: Dan Schatzberg Cc: Dan Schatzberg , Johannes Weiner , Tejun Heo , Chris Down , Shakeel Butt , Jens Axboe , Alexander Viro , Jan Kara , Amir Goldstein , Li Zefan , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , Roman Gushchin , Yang Shi , Thomas Gleixner , Ingo Molnar , "Peter Zijlstra (Intel)" , Mathieu Desnoyers , Andrea Arcangeli , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)) Subject: [PATCH 3/4] mm: Charge active memcg when no mm is set Date: Thu, 28 May 2020 09:54:38 -0400 Message-Id: <20200528135444.11508-4-schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200528135444.11508-1-schatzberg.dan@gmail.com> References: <20200528135444.11508-1-schatzberg.dan@gmail.com> 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 --- mm/memcontrol.c | 11 ++++++++--- mm/shmem.c | 4 ++-- 2 files changed, 10 insertions(+), 5 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a3b97f103966..383d88c1c105 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6438,7 +6438,8 @@ 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. @@ -6482,8 +6483,12 @@ 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 bd8840082c94..d2efa1a44311 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1618,7 +1618,7 @@ static int shmem_swapin_page(struct inode *inode, pgoff_t index, { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); - struct mm_struct *charge_mm = vma ? vma->vm_mm : current->mm; + struct mm_struct *charge_mm = vma ? vma->vm_mm : NULL; struct mem_cgroup *memcg; struct page *page; swp_entry_t swap; @@ -1753,7 +1753,7 @@ 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 May 28 13:54:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 11575907 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 E46A0912 for ; Thu, 28 May 2020 13:55:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE7FF2084C for ; Thu, 28 May 2020 13:55:47 +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="i53O/UF2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390824AbgE1Nzi (ORCPT ); Thu, 28 May 2020 09:55:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36728 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390819AbgE1Nzg (ORCPT ); Thu, 28 May 2020 09:55:36 -0400 Received: from mail-qv1-xf44.google.com (mail-qv1-xf44.google.com [IPv6:2607:f8b0:4864:20::f44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BBB5C08C5C6; Thu, 28 May 2020 06:55:35 -0700 (PDT) Received: by mail-qv1-xf44.google.com with SMTP id fb16so12936666qvb.5; Thu, 28 May 2020 06:55:35 -0700 (PDT) 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=yCJxjVJiob7hrGW2G0hac/uRBBnyrQcSugyMn+QGSV8=; b=i53O/UF2kb4RA4KjhpHC1Gs+OtOPnxOi5MfZ4OSSy2trR0+NlLFc/GosjZ+mzjL19N 5mCHWxF97TRry2CrW8OkXlh9bCrYVtgP9n681qY9kjTsUKGVgT5HrZ3eTp2sOpJpgaFr KxJsoprg8zR10dxc5jhPtGhLP3h8/W+qnYEUhhiBvLJT+CwKSwFTjMjhkjmotCyfe/RR 01QErMQa66u0OitMD/t56OwLwCvo3ys3+rjVXYf1++f2ziwb0OGuwy2/7Y22HAmSKPeT F9XUq0SiEkdYISJDWbzHbqJVkJ4N7Z6rqxs5UeWM7I0CY0rPj6wwIrcUOoncNsNZ+Ef0 I+fg== 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=yCJxjVJiob7hrGW2G0hac/uRBBnyrQcSugyMn+QGSV8=; b=NSbT4us+0Es2WpPID4FB+Em5QH3WFixODiVTMZA2sk1n4/o0MVyk3pdlceM8vIvvYl LOCYZLVIew0T9ZNK5GjkwoBPzXWmLoV0tstLsKI9Dn84AxV809wjxbM/LUWu4N/jeVfb Mgi9hnXRN1uGHHHfF1GduQedNnAI6jrB1KZrTqFdh+cvnfYhvpf08UrWc1MePuvg1jrl yZkLHGs1CeIh8BX9wohhMIFimvZg6BPDcla6eyaI40HhtRm4yG/Kjh1t6pjo8OJmOBkc Nhp8ofNrVITRhvwQgE64plNVupVhgsc5h18ZxqAs9dW9dS6EFTKHpvQfUCS6x2OESvM/ 8QjQ== X-Gm-Message-State: AOAM533bCFx2HZ0dAyeaZ3p8zNjCntCoib9tjrtpRyBl8KvQkiyrHDqM UEhgkrKEFtJOiF7Vrm2g3eU= X-Google-Smtp-Source: ABdhPJylE92oI6jHfDbTTrXTlaHaVrUvMYYQ9jygJwokJdb7mbT1IW4tfg5rcEVPwZO1V1DoJXTHmA== X-Received: by 2002:a0c:8c4a:: with SMTP id o10mr3220133qvb.123.1590674134267; Thu, 28 May 2020 06:55:34 -0700 (PDT) Received: from dschatzberg-fedora-PC0Y6AEN.thefacebook.com ([2620:10d:c091:480::1:1cb7]) by smtp.gmail.com with ESMTPSA id l186sm4890889qkf.89.2020.05.28.06.55.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 May 2020 06:55:33 -0700 (PDT) From: Dan Schatzberg Cc: Dan Schatzberg , Johannes Weiner , Jens Axboe , Alexander Viro , Jan Kara , Amir Goldstein , Tejun Heo , Li Zefan , Michal Hocko , Vladimir Davydov , Andrew Morton , Hugh Dickins , Roman Gushchin , Shakeel Butt , Chris Down , Yang Shi , Thomas Gleixner , "Peter Zijlstra (Intel)" , Ingo Molnar , Mathieu Desnoyers , Andrea Arcangeli , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), linux-fsdevel@vger.kernel.org (open list:FILESYSTEMS (VFS and infrastructure)), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)) Subject: [PATCH 4/4] loop: Charge i/o to mem and blk cg Date: Thu, 28 May 2020 09:54:39 -0400 Message-Id: <20200528135444.11508-5-schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200528135444.11508-1-schatzberg.dan@gmail.com> References: <20200528135444.11508-1-schatzberg.dan@gmail.com> 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 | 61 +++++++++++++++++++++++++------------- drivers/block/loop.h | 3 +- include/linux/memcontrol.h | 6 ++++ kernel/cgroup/cgroup.c | 1 + 4 files changed, 50 insertions(+), 21 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 378a68e5ccf3..c238e274788e 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -77,6 +77,7 @@ #include #include #include +#include #include "loop.h" @@ -507,8 +508,6 @@ 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); } @@ -569,8 +568,6 @@ 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); @@ -578,7 +575,6 @@ 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); @@ -918,7 +914,7 @@ 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; }; @@ -935,7 +931,7 @@ static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd) spin_lock_irq(&lo->lo_work_lock); - if (!cmd->css) + if (!cmd->blkcg_css) goto queue_work; node = &lo->worker_tree.rb_node; @@ -943,10 +939,10 @@ 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 (cur_worker->css == cmd->css) { + if (cur_worker->blkcg_css == 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; @@ -958,13 +954,18 @@ static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd) worker = kzalloc(sizeof(struct loop_worker), 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; + if (cmd->memcg_css) + css_put(cmd->memcg_css); + 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); @@ -1214,7 +1215,7 @@ static int __loop_clr_fd(struct loop_device *lo, bool release) idle_list) { list_del(&worker->idle_list); rb_erase(&worker->rb_node, &lo->worker_tree); - css_put(worker->css); + css_put(worker->blkcg_css); kfree(worker); } spin_unlock_irq(&lo->lo_work_lock); @@ -2027,13 +2028,18 @@ 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; @@ -2045,13 +2051,28 @@ static void loop_handle_cmd(struct loop_cmd *cmd) const bool write = op_is_write(req_op(rq)); struct loop_device *lo = rq->q->queuedata; int ret = 0; + struct mem_cgroup *old_memcg = NULL; if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) { ret = -EIO; goto failed; } + if (cmd->blkcg_css) + kthread_associate_blkcg(cmd->blkcg_css); + if (cmd->memcg_css) + old_memcg = memalloc_use_memcg( + mem_cgroup_from_css(cmd->memcg_css)); + ret = do_req_filebacked(lo, rq); + + if (cmd->blkcg_css) + kthread_associate_blkcg(NULL); + + if (cmd->memcg_css) { + memalloc_use_memcg(old_memcg); + css_put(cmd->memcg_css); + } failed: /* complete non-aio request */ if (!cmd->use_aio || ret) { @@ -2129,7 +2150,7 @@ 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 0162b55a68e1..4d6886d9855a 100644 --- a/drivers/block/loop.h +++ b/drivers/block/loop.h @@ -75,7 +75,8 @@ 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 977edd3b7bd8..67a98db5be9e 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -925,6 +925,12 @@ 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 06b5ea9d899d..a3c64d961d68 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) {