From patchwork Mon Apr 6 19:58:18 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tejun Heo X-Patchwork-Id: 6165131 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 4D340BF4A6 for ; Mon, 6 Apr 2015 20:16:00 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4BADF20303 for ; Mon, 6 Apr 2015 20:15:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 12186202EC for ; Mon, 6 Apr 2015 20:15:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754082AbbDFUPk (ORCPT ); Mon, 6 Apr 2015 16:15:40 -0400 Received: from mail-qc0-f171.google.com ([209.85.216.171]:36400 "EHLO mail-qc0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753366AbbDFT7m (ORCPT ); Mon, 6 Apr 2015 15:59:42 -0400 Received: by qcgx3 with SMTP id x3so15060783qcg.3; Mon, 06 Apr 2015 12:59:41 -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=geDi2OSckqNP0SA+jbLF/rmxpE47x5Mri12LYa1eUp0=; b=xtDXp++M5B3ISiTIQY7EarRL+qIJQc33lNNwYrkBvBFwmk1MWhIf2v4w3EZYpCut/G XgnnkH7auT3uwOPBKQrAmTrTHJo0t+eN6f4jobSN4wY8Q/R5MiyBUMG1Lle8IWvjiInM KcRFVlXCa7v1jowMHkHp+olNlzK0xBRnRh7LkR+wVlcHOXinDMZTPYS4gsVGG4LqmpCu RodssbWRjVZ2WdVbin015B9w0jzxWrCupIr7bHUws6yOtHG1QXguOlG83YfJnQS6oS9h 1QnLLUidIQlCxm/xQ9x2PxVQvZxurRZp0fwKlNASoFHY/d33URwvdt9UJs5ov35SLK12 CeMw== X-Received: by 10.55.52.20 with SMTP id b20mr32105028qka.34.1428350381269; Mon, 06 Apr 2015 12:59:41 -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 z67sm3914418qgz.10.2015.04.06.12.59.39 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 06 Apr 2015 12:59:40 -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, Tejun Heo Subject: [PATCH 29/49] writeback: implement and use inode_congested() Date: Mon, 6 Apr 2015 15:58:18 -0400 Message-Id: <1428350318-8215-30-git-send-email-tj@kernel.org> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1428350318-8215-1-git-send-email-tj@kernel.org> References: <1428350318-8215-1-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 In several places, bdi_congested() and its wrappers are used to determine whether more IOs should be issued. With cgroup writeback support, this question can't be answered solely based on the bdi (backing_dev_info). It's dependent on whether the filesystem and bdi support cgroup writeback and the blkcg the inode is associated with. This patch implements inode_congested() and its wrappers which take @inode and determines the congestion state considering cgroup writeback. The new functions replace bdi_*congested() calls in places where the query is about specific inode and task. There are several filesystem users which also fit this criteria but they should be updated when each filesystem implements cgroup writeback support. v2: Now that a given inode is associated with only one wb, congestion state can be determined independent from the asking task. Drop @task. Spotted by Vivek. Also, converted to take @inode instead of @mapping and renamed to inode_congested(). Signed-off-by: Tejun Heo Cc: Jens Axboe Cc: Jan Kara Cc: Vivek Goyal --- fs/fs-writeback.c | 29 +++++++++++++++++++++++++++++ include/linux/backing-dev.h | 22 ++++++++++++++++++++++ mm/fadvise.c | 2 +- mm/readahead.c | 2 +- mm/vmscan.c | 11 +++++------ 5 files changed, 58 insertions(+), 8 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 48db5e6..1d30249 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -130,6 +130,35 @@ static void __wb_start_writeback(struct bdi_writeback *wb, long nr_pages, wb_queue_work(wb, work); } +#ifdef CONFIG_CGROUP_WRITEBACK + +/** + * inode_congested - test whether an inode is congested + * @inode: inode to test for congestion + * @cong_bits: mask of WB_[a]sync_congested bits to test + * + * Tests whether @inode is congested. @cong_bits is the mask of congestion + * bits to test and the return value is the mask of set bits. + * + * If cgroup writeback is enabled for @inode, the congestion state is + * determined by whether the cgwb (cgroup bdi_writeback) for the blkcg + * associated with @inode is congested; otherwise, the root wb's congestion + * state is used. + */ +int inode_congested(struct inode *inode, int cong_bits) +{ + if (inode) { + struct bdi_writeback *wb = inode_to_wb(inode); + if (wb) + return wb_congested(wb, cong_bits); + } + + return wb_congested(&inode_to_bdi(inode)->wb, cong_bits); +} +EXPORT_SYMBOL_GPL(inode_congested); + +#endif /* CONFIG_CGROUP_WRITEBACK */ + /** * bdi_start_writeback - start writeback * @bdi: the backing device to write from diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 2c498a2..6f08821 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -230,6 +230,7 @@ struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, void __inode_attach_wb(struct inode *inode, struct page *page); void wb_memcg_offline(struct mem_cgroup *memcg); void wb_blkcg_offline(struct blkcg *blkcg); +int inode_congested(struct inode *inode, int cong_bits); /** * inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode @@ -438,8 +439,29 @@ static inline void wb_blkcg_offline(struct blkcg *blkcg) { } +static inline int inode_congested(struct inode *inode, int cong_bits) +{ + return wb_congested(&inode_to_bdi(inode)->wb, cong_bits); +} + #endif /* CONFIG_CGROUP_WRITEBACK */ +static inline int inode_read_congested(struct inode *inode) +{ + return inode_congested(inode, 1 << WB_sync_congested); +} + +static inline int inode_write_congested(struct inode *inode) +{ + return inode_congested(inode, 1 << WB_async_congested); +} + +static inline int inode_rw_congested(struct inode *inode) +{ + return inode_congested(inode, (1 << WB_sync_congested) | + (1 << WB_async_congested)); +} + static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits) { return wb_congested(&bdi->wb, cong_bits); diff --git a/mm/fadvise.c b/mm/fadvise.c index 4a3907c..b8a5bc6 100644 --- a/mm/fadvise.c +++ b/mm/fadvise.c @@ -115,7 +115,7 @@ SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice) case POSIX_FADV_NOREUSE: break; case POSIX_FADV_DONTNEED: - if (!bdi_write_congested(bdi)) + if (!inode_write_congested(mapping->host)) __filemap_fdatawrite_range(mapping, offset, endbyte, WB_SYNC_NONE); diff --git a/mm/readahead.c b/mm/readahead.c index 9356758..60cd846 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -541,7 +541,7 @@ page_cache_async_readahead(struct address_space *mapping, /* * Defer asynchronous read-ahead on IO congestion. */ - if (bdi_read_congested(inode_to_bdi(mapping->host))) + if (inode_read_congested(mapping->host)) return; /* do read-ahead */ diff --git a/mm/vmscan.c b/mm/vmscan.c index 7582f9f..f463398 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -452,14 +452,13 @@ static inline int is_page_cache_freeable(struct page *page) return page_count(page) - page_has_private(page) == 2; } -static int may_write_to_queue(struct backing_dev_info *bdi, - struct scan_control *sc) +static int may_write_to_inode(struct inode *inode, struct scan_control *sc) { if (current->flags & PF_SWAPWRITE) return 1; - if (!bdi_write_congested(bdi)) + if (!inode_write_congested(inode)) return 1; - if (bdi == current->backing_dev_info) + if (inode_to_bdi(inode) == current->backing_dev_info) return 1; return 0; } @@ -538,7 +537,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping, } if (mapping->a_ops->writepage == NULL) return PAGE_ACTIVATE; - if (!may_write_to_queue(inode_to_bdi(mapping->host), sc)) + if (!may_write_to_inode(mapping->host, sc)) return PAGE_KEEP; if (clear_page_dirty_for_io(page)) { @@ -924,7 +923,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, */ mapping = page_mapping(page); if (((dirty || writeback) && mapping && - bdi_write_congested(inode_to_bdi(mapping->host))) || + inode_write_congested(mapping->host)) || (writeback && PageReclaim(page))) nr_congested++;