From patchwork Mon Aug 24 15:36:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 11733573 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 0797A14F6 for ; Mon, 24 Aug 2020 15:43:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB4F820838 for ; Mon, 24 Aug 2020 15:43:44 +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="VQndbuWT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728029AbgHXPnh (ORCPT ); Mon, 24 Aug 2020 11:43:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727906AbgHXPhy (ORCPT ); Mon, 24 Aug 2020 11:37:54 -0400 Received: from mail-qk1-x742.google.com (mail-qk1-x742.google.com [IPv6:2607:f8b0:4864:20::742]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCE69C061755; Mon, 24 Aug 2020 08:37:53 -0700 (PDT) Received: by mail-qk1-x742.google.com with SMTP id p25so7772696qkp.2; Mon, 24 Aug 2020 08:37:53 -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=mquvtW23tRDFpTzlE8ED31sKF5mD/fykcSWQYhD45BU=; b=VQndbuWT0DpMkgBvLsSdvUtHrXVHJg/0kHEHKUEC1QP49Pr+63PJxHzhd3pNfj3cE2 w+V+dNXbF3sTSirWF7gaOJ3T+HfJvWyurbegfBgH+mov0Yeeo/+Y8XDUDYXNK4vAg1+P vYeWh9Kifo/FMz/LtHY0tuaz6IRCY1GwT0Vhnp2FWB88M49/XXUINpHWJKeANg4iVJfw EQbtf2vlcCQMYqWipvj0qJWCizJlBz8NU8YzlRD2ARqb1lhqZoQQFl/tD3VV4gRG9SHX tBD20mk3xwRvhLfu5R6xHCDr5zRliPHMga3p6S/zDQkp1VL0/pw9bxQhBkmHQpbE3thu 4oNQ== 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=mquvtW23tRDFpTzlE8ED31sKF5mD/fykcSWQYhD45BU=; b=awNeO0f1jpUjMwksyfyWha25lifYcYl8X2gDfD7YBSQ8DN3wKz/Zczeqzx1yd9s8l1 vVW+Hvt6HRYqUeCuF4LjEWhD1FQn1IRpzHw5uVFggL2A6hY8ciI0s/jeieSofnX7yV7T xUXvzPepad/kbk9hLQSBru1L1rPdCBdqdaW/hPTmZWUFCldQfmNQU/8L482bSvNayJjQ mIz72lyMr1NqmLN0KSoKobEsjySXUatDuZdINOFjWVszAqNq5b9g9ZAIBzqbNtYUa5Ac 15Ev1MXJRNfO410dDDaqZ5GBCOkHXetAuXvi80RE3HLsOaLsnp3AmhnQmIoTpG7ObWlx Qe6w== X-Gm-Message-State: AOAM532JQqrTivSK6WBliVObB5f2B0qQF4SifBu76Z8QhQfJ+HlY7FID EUtNMjv//RAj75tqVerYKLg= X-Google-Smtp-Source: ABdhPJzJjdDOQad2laWQlBUh5PHQTffnEUZUiD1WjHvuoiLiKZf3WYj1pDuFgKRE59dbEmD+DMzBCA== X-Received: by 2002:a37:8484:: with SMTP id g126mr5112716qkd.230.1598283472942; Mon, 24 Aug 2020 08:37:52 -0700 (PDT) Received: from dschatzberg-fedora-PC0Y6AEN.thefacebook.com ([2620:10d:c091:480::1:dd21]) by smtp.gmail.com with ESMTPSA id m17sm10942758qkn.45.2020.08.24.08.37.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Aug 2020 08:37:52 -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 , Joonsoo Kim , Chris Down , Yafang Shao , Yang Shi , Peter Zijlstra , Ingo Molnar , Mathieu Desnoyers , Daniel Jordan , Michel Lespinasse , Thomas Gleixner , 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: Mon, 24 Aug 2020 11:36:00 -0400 Message-Id: <20200824153607.6595-3-schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200824153607.6595-1-schatzberg.dan@gmail.com> References: <20200824153607.6595-1-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 +++++++++------------------- mm/memcontrol.c | 6 +++--- 5 files changed, 21 insertions(+), 29 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index d468ed9981e0..804170cb59fe 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -842,13 +842,13 @@ 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; @@ -867,7 +867,7 @@ 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 c942910a8649..c8fd563e02a3 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -533,6 +533,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS); struct inode *child = NULL; bool name_event = false; + struct mem_cgroup *old_memcg; if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) { /* @@ -580,7 +581,7 @@ static 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)) { event = fanotify_alloc_perm_event(path, gfp); @@ -608,7 +609,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, event->pid = get_pid(task_tgid(current)); 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 a65cf8c9f600..8017a51561c4 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -66,6 +66,7 @@ static int inotify_one_event(struct fsnotify_group *group, u32 mask, int ret; int len = 0; int alloc_len = sizeof(struct inotify_event_info); + struct mem_cgroup *old_memcg; if ((inode_mark->mask & FS_EXCL_UNLINK) && path && d_unlinked(path->dentry)) @@ -87,9 +88,9 @@ static int inotify_one_event(struct fsnotify_group *group, u32 mask, * 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 f889e332912f..b8fde48d44a9 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -312,31 +312,21 @@ 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 diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b807952b4d43..b2468c80085d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5271,12 +5271,12 @@ static struct cgroup_subsys_state * __ref mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { struct mem_cgroup *parent = mem_cgroup_from_css(parent_css); - struct mem_cgroup *memcg; + struct mem_cgroup *memcg, *old_memcg; long error = -ENOMEM; - memalloc_use_memcg(parent); + old_memcg = memalloc_use_memcg(parent); memcg = mem_cgroup_alloc(); - memalloc_unuse_memcg(); + memalloc_use_memcg(old_memcg); if (IS_ERR(memcg)) return ERR_CAST(memcg);