From patchwork Tue Mar 22 21:39:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12789052 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6BB4C433F5 for ; Tue, 22 Mar 2022 21:39:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5B5106B0082; Tue, 22 Mar 2022 17:39:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 563E76B0083; Tue, 22 Mar 2022 17:39:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4536A6B0085; Tue, 22 Mar 2022 17:39:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0081.hostedemail.com [216.40.44.81]) by kanga.kvack.org (Postfix) with ESMTP id 363366B0082 for ; Tue, 22 Mar 2022 17:39:05 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id D9FD61828AC92 for ; Tue, 22 Mar 2022 21:39:04 +0000 (UTC) X-FDA: 79273337808.18.EF2C58C Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf10.hostedemail.com (Postfix) with ESMTP id 42A71C002A for ; Tue, 22 Mar 2022 21:39:04 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 122BCB81D9E; Tue, 22 Mar 2022 21:39:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C18FBC340EC; Tue, 22 Mar 2022 21:39:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1647985141; bh=uWkJGJ2N+nvR3L+pGd9iSgDBQla/4Y6wR2/ld2flBDU=; h=Date:To:From:In-Reply-To:Subject:From; b=hQHwlLGVUU4B9VtwY0U3wE0dRXtmMQM8+ojPEz1gpwGGqqJZ9/04xbsiUiRKDdVJx JPj8x6NznFF4VVpQ8D/uOGg8oehPnOOIu+oDOOnbpOJ40FMm3ZSjHW07I79EjU8ERJ YmuNWH2hQhP+Zh1NlJ2mem87a8iA+QfrD0/4URrU= Date: Tue, 22 Mar 2022 14:39:01 -0700 To: trond.myklebust@hammerspace.com,philipp.reisner@linbit.com,paolo.valente@linaro.org,miklos@szeredi.hu,lars.ellenberg@linbit.com,konishi.ryusuke@gmail.com,jlayton@kernel.org,jaegeuk@kernel.org,jack@suse.cz,idryomov@gmail.com,fengguang.wu@intel.com,djwong@kernel.org,chao@kernel.org,axboe@kernel.dk,Anna.Schumaker@Netapp.com,neilb@suse.de,akpm@linux-foundation.org,patches@lists.linux.dev,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org From: Andrew Morton In-Reply-To: <20220322143803.04a5e59a07e48284f196a2f9@linux-foundation.org> Subject: [patch 010/227] nfs: remove reliance on bdi congestion Message-Id: <20220322213901.C18FBC340EC@smtp.kernel.org> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 42A71C002A X-Stat-Signature: aw6m4xscjsp94y4gz4rjff7z9uebsoz9 X-Rspam-User: Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=hQHwlLGV; dmarc=none; spf=pass (imf10.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-HE-Tag: 1647985144-560577 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: NeilBrown Subject: nfs: remove reliance on bdi congestion The bdi congestion tracking in not widely used and will be removed. NFS is one of a small number of filesystems that uses it, setting just the async (write) congestion flag at what it determines are appropriate times. The only remaining effect of the async flag is to cause (some) WB_SYNC_NONE writes to be skipped. So instead of setting the flag, set an internal flag and change: - .writepages to do nothing if WB_SYNC_NONE and the flag is set - .writepage to return AOP_WRITEPAGE_ACTIVATE if WB_SYNC_NONE and the flag is set. The writepages change causes a behavioural change in that pageout() can now return PAGE_ACTIVATE instead of PAGE_KEEP, so SetPageActive() will be called on the page which (I think) wil further delay the next attempt at writeout. This might be a good thing. Link: https://lkml.kernel.org/r/164549983738.9187.3972219847989393182.stgit@noble.brown Signed-off-by: NeilBrown Cc: Anna Schumaker Cc: Chao Yu Cc: Darrick J. Wong Cc: Ilya Dryomov Cc: Jaegeuk Kim Cc: Jan Kara Cc: Jeff Layton Cc: Jens Axboe Cc: Lars Ellenberg Cc: Miklos Szeredi Cc: Paolo Valente Cc: Philipp Reisner Cc: Ryusuke Konishi Cc: Trond Myklebust Cc: Wu Fengguang Signed-off-by: Andrew Morton --- fs/nfs/write.c | 14 +++++++++++--- include/linux/nfs_fs_sb.h | 1 + 2 files changed, 12 insertions(+), 3 deletions(-) --- a/fs/nfs/write.c~nfs-remove-reliance-on-bdi-congestion +++ a/fs/nfs/write.c @@ -417,7 +417,7 @@ static void nfs_set_page_writeback(struc if (atomic_long_inc_return(&nfss->writeback) > NFS_CONGESTION_ON_THRESH) - set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC); + nfss->write_congested = 1; } static void nfs_end_page_writeback(struct nfs_page *req) @@ -433,7 +433,7 @@ static void nfs_end_page_writeback(struc end_page_writeback(req->wb_page); if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) - clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC); + nfss->write_congested = 0; } /* @@ -672,6 +672,10 @@ static int nfs_writepage_locked(struct p struct inode *inode = page_file_mapping(page)->host; int err; + if (wbc->sync_mode == WB_SYNC_NONE && + NFS_SERVER(inode)->write_congested) + return AOP_WRITEPAGE_ACTIVATE; + nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE); nfs_pageio_init_write(&pgio, inode, 0, false, &nfs_async_write_completion_ops); @@ -719,6 +723,10 @@ int nfs_writepages(struct address_space int priority = 0; int err; + if (wbc->sync_mode == WB_SYNC_NONE && + NFS_SERVER(inode)->write_congested) + return 0; + nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES); if (!(mntflags & NFS_MOUNT_WRITE_EAGER) || wbc->for_kupdate || @@ -1893,7 +1901,7 @@ static void nfs_commit_release_pages(str } nfss = NFS_SERVER(data->inode); if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) - clear_bdi_congested(inode_to_bdi(data->inode), BLK_RW_ASYNC); + nfss->write_congested = 0; nfs_init_cinfo(&cinfo, data->inode, data->dreq); nfs_commit_end(cinfo.mds); --- a/include/linux/nfs_fs_sb.h~nfs-remove-reliance-on-bdi-congestion +++ a/include/linux/nfs_fs_sb.h @@ -138,6 +138,7 @@ struct nfs_server { struct nlm_host *nlm_host; /* NLM client handle */ struct nfs_iostats __percpu *io_stats; /* I/O statistics */ atomic_long_t writeback; /* number of writeback pages */ + unsigned int write_congested;/* flag set when writeback gets too high */ unsigned int flags; /* various flags */ /* The following are for internal use only. Also see uapi/linux/nfs_mount.h */