From patchwork Fri May 22 21:13:50 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tejun Heo X-Patchwork-Id: 6468361 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id DDA41C0020 for ; Fri, 22 May 2015 21:21:22 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0522F20513 for ; Fri, 22 May 2015 21:21:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0E8F720511 for ; Fri, 22 May 2015 21:21:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758063AbbEVVPb (ORCPT ); Fri, 22 May 2015 17:15:31 -0400 Received: from mail-qg0-f52.google.com ([209.85.192.52]:33999 "EHLO mail-qg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757993AbbEVVP1 (ORCPT ); Fri, 22 May 2015 17:15:27 -0400 Received: by qgez61 with SMTP id z61so16260541qge.1; Fri, 22 May 2015 14:15:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=BRBuKWthd1YeGpDEsuBdqVDhvdxyzsMxKqpEib1wICo=; b=N/6LlKU8EeWuYPh5Drxk3DZIKI1y1seeaKstSOBIPF3sAVWWoj7gaZ/fHFqJrh1Qhw 9cLjxxRUFZZVqdsQe60uGf56nrbgXg5A23tmiCP3hoBxWfA9rC694EvuSEjY1yHZ9+Ex nZ4HKcckU1qsfgjgQiLD2fawUBRpdoqkGN+Rb91FJoBn/T3nE7LEM+jNRPIXqeai1rCx IlyvoIdbgfJ0PXejEs8+pi1BcokRgpYdGv06Gsc/RUzQHtBwJ0k/DPEMKOS3kXXd2naU g4h6/jllm2eRhQoYqErAjcgUmIMylI0dYQkENB3QYRku0iaLYoK0/PGa9AhGbZTTTjhD Nwew== X-Received: by 10.140.48.103 with SMTP id n94mr13625403qga.8.1432329326489; Fri, 22 May 2015 14:15:26 -0700 (PDT) Received: from htj.duckdns.org.lan (207-38-238-8.c3-0.wsd-ubr1.qens-wsd.ny.cable.rcn.com. [207.38.238.8]) by mx.google.com with ESMTPSA id v1sm2059653qge.47.2015.05.22.14.15.24 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 22 May 2015 14:15:25 -0700 (PDT) From: Tejun Heo To: axboe@kernel.dk Cc: linux-kernel@vger.kernel.org, jack@suse.cz, hch@infradead.org, hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org, vgoyal@redhat.com, lizefan@huawei.com, cgroups@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.cz, clm@fb.com, fengguang.wu@intel.com, david@fromorbit.com, gthelen@google.com, khlebnikov@yandex-team.ru, Tejun Heo Subject: [PATCH 36/51] writeback: implement bdi_for_each_wb() Date: Fri, 22 May 2015 17:13:50 -0400 Message-Id: <1432329245-5844-37-git-send-email-tj@kernel.org> X-Mailer: git-send-email 2.4.0 In-Reply-To: <1432329245-5844-1-git-send-email-tj@kernel.org> References: <1432329245-5844-1-git-send-email-tj@kernel.org> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID,T_RP_MATCHES_RCVD,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This will be used to implement bdi-wide operations which should be distributed across all its cgroup bdi_writebacks. Signed-off-by: Tejun Heo Cc: Jens Axboe Cc: Jan Kara --- include/linux/backing-dev.h | 63 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 0839e44..c797980 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -383,6 +383,61 @@ static inline struct bdi_writeback *inode_to_wb(struct inode *inode) return inode->i_wb; } +struct wb_iter { + int start_blkcg_id; + struct radix_tree_iter tree_iter; + void **slot; +}; + +static inline struct bdi_writeback *__wb_iter_next(struct wb_iter *iter, + struct backing_dev_info *bdi) +{ + struct radix_tree_iter *titer = &iter->tree_iter; + + WARN_ON_ONCE(!rcu_read_lock_held()); + + if (iter->start_blkcg_id >= 0) { + iter->slot = radix_tree_iter_init(titer, iter->start_blkcg_id); + iter->start_blkcg_id = -1; + } else { + iter->slot = radix_tree_next_slot(iter->slot, titer, 0); + } + + if (!iter->slot) + iter->slot = radix_tree_next_chunk(&bdi->cgwb_tree, titer, 0); + if (iter->slot) + return *iter->slot; + return NULL; +} + +static inline struct bdi_writeback *__wb_iter_init(struct wb_iter *iter, + struct backing_dev_info *bdi, + int start_blkcg_id) +{ + iter->start_blkcg_id = start_blkcg_id; + + if (start_blkcg_id) + return __wb_iter_next(iter, bdi); + else + return &bdi->wb; +} + +/** + * bdi_for_each_wb - walk all wb's of a bdi in ascending blkcg ID order + * @wb_cur: cursor struct bdi_writeback pointer + * @bdi: bdi to walk wb's of + * @iter: pointer to struct wb_iter to be used as iteration buffer + * @start_blkcg_id: blkcg ID to start iteration from + * + * Iterate @wb_cur through the wb's (bdi_writeback's) of @bdi in ascending + * blkcg ID order starting from @start_blkcg_id. @iter is struct wb_iter + * to be used as temp storage during iteration. rcu_read_lock() must be + * held throughout iteration. + */ +#define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id) \ + for ((wb_cur) = __wb_iter_init(iter, bdi, start_blkcg_id); \ + (wb_cur); (wb_cur) = __wb_iter_next(iter, bdi)) + #else /* CONFIG_CGROUP_WRITEBACK */ static inline bool inode_cgwb_enabled(struct inode *inode) @@ -445,6 +500,14 @@ static inline void wb_blkcg_offline(struct blkcg *blkcg) { } +struct wb_iter { + int next_id; +}; + +#define bdi_for_each_wb(wb_cur, bdi, iter, start_blkcg_id) \ + for ((iter)->next_id = (start_blkcg_id); \ + ({ (wb_cur) = !(iter)->next_id++ ? &(bdi)->wb : NULL; }); ) + static inline int inode_congested(struct inode *inode, int cong_bits) { return wb_congested(&inode_to_bdi(inode)->wb, cong_bits);