From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: [PATCH 05/11] nfs: remove reliance on bdi congestion Date: Tue, 22 Feb 2022 14:17:17 +1100 Message-ID: <164549983738.9187.3972219847989393182.stgit@noble.brown> References: <164549971112.9187.16871723439770288255.stgit@noble.brown> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:Content-Type:MIME-Version :References:In-Reply-To:Message-ID:Date:Cc:To:From:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=CRQpTl6gU6MaBAdfwSalgYu+ynBw18B3JAwgtU5P7zs=; b=k0losm/ZoDGKxWvqsnjcg4TSa2 m4cy2TnnnnosSkoKW+DZU/58+sE4Tcz+nnrZBdhT1DwSNORzZ5VjUdzIZY0v+sdoWhaPmEqSE/7Is SkSnaBk3pWOP7gzOJM83uLtT2kfrBIVYMBS9PnMdXUt+pAXgMtiSmtDdH3Cr9rssC6ZA=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References: In-Reply-To:Message-ID:Date:Cc:To:From:Subject:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=CRQpTl6gU6MaBAdfwSalgYu+ynBw18B3JAwgtU5P7zs=; b=WKNeXgv5ZTM5rlG77EAOw5i7RG ZOZum11cQcsxERSHZI7EyQblbooc6Znaml9EMaZKDKicSaI61q5rekSL+Wh/x2n3ezKYUjjzKe4nv sSFlzqFzftjZWevxrQmfRt1wLXyg7J5FmAOMM0d8vaCMZk71++e69gu5LbzSYOqglFxo=; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1645499938; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CRQpTl6gU6MaBAdfwSalgYu+ynBw18B3JAwgtU5P7zs=; b=rAWmkDzMUq5saT4diV9iyBOxbbUTYHnUd2tyt0hXJjU6qv76OdiJ5quclkFkgkZQZIH/wp djrbwIjn2UoPBOT7mgohYOdjGbrka++Z8N5ut87wSQClx58gfzi3CCtWd2zWBc047trrfv Pk48nRu5043YQll4VCkTE6CkokYW/jI= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1645499938; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CRQpTl6gU6MaBAdfwSalgYu+ynBw18B3JAwgtU5P7zs=; b=78ppJZNYmM3wJ075e/NaA+H//budRLqxkm37FXGyz0tkz7p2NRq8afWahvYZOHCZpahi12 jM7r94+t4KDXnMBQ== In-Reply-To: <164549971112.9187.16871723439770288255.stgit@noble.brown> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Andrew Morton , Jan Kara , Wu Fengguang , Jaegeuk Kim , Chao Yu , Jeff Layton , Ilya Dryomov , Miklos Szeredi , Trond Myklebust , Anna Schumaker , Ryusuke Konishi , "Darrick J. Wong" , Philipp Reisner , Lars Ellenberg , Paolo Valente , Jens Axboe Cc: linux-nfs@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, ceph-devel@vger.kernel.org, linux-ext4@vger.kernel.org, drbd-dev@lists.linbit.com 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. Signed-off-by: NeilBrown --- fs/nfs/write.c | 14 +++++++++++--- include/linux/nfs_fs_sb.h | 1 + 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 987a187bd39a..7c986164018e 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -417,7 +417,7 @@ static void nfs_set_page_writeback(struct page *page) 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(struct nfs_page *req) 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 page *page, 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 *mapping, struct writeback_control *wbc) 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(struct nfs_commit_data *data) } 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); diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h index ca0959e51e81..6aa2a200676a 100644 --- a/include/linux/nfs_fs_sb.h +++ b/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 */