From patchwork Thu Feb 10 05:37:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 541463 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8378AC433EF for ; Thu, 10 Feb 2022 05:40:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234465AbiBJFk1 (ORCPT ); Thu, 10 Feb 2022 00:40:27 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:36092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234474AbiBJFjr (ORCPT ); Thu, 10 Feb 2022 00:39:47 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D354310C7; Wed, 9 Feb 2022 21:39:20 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 8E8711F43D; Thu, 10 Feb 2022 05:39:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1644471559; 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=j2iKmKfQAV47ltxyUTpJL5kF151jPpkpJZBMxZj0hPA=; b=uKgETFLiX7EG3eRXPuLaRXJzGwKmI41Y099K5XW1KSBpIkvAtu7aaGjeLAQGXG8TUQFaYO OMbK9eXz4PZqR02yAAtlGS6TlPoP/iTMR8GqWOZjaexFnysfcGLyRc7rr/3yf9JBO9+gKt oZC/hm6/xktjcHUh7EOUlnr9KfhiLHA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1644471559; 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=j2iKmKfQAV47ltxyUTpJL5kF151jPpkpJZBMxZj0hPA=; b=tFH7OafqVWs9TyFo1hmlUCp9XAM4aJZnlfF1apQOnbWq4IG7Y1nuHRPilxWK+gi9ecSy8b ySE9dRcAQmytzwCw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 3C0FA13519; Thu, 10 Feb 2022 05:39:11 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id KeDlOv+kBGLuOAAAMHmgww (envelope-from ); Thu, 10 Feb 2022 05:39:11 +0000 Subject: [PATCH 04/11] fuse: remove reliance on bdi congestion From: NeilBrown 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-doc@vger.kernel.org, linux-mm@kvack.org, linux-nilfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-ext4@vger.kernel.org, ceph-devel@vger.kernel.org, drbd-dev@lists.linbit.com, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Date: Thu, 10 Feb 2022 16:37:52 +1100 Message-ID: <164447147258.23354.13665933242616399479.stgit@noble.brown> In-Reply-To: <164447124918.23354.17858831070003318849.stgit@noble.brown> References: <164447124918.23354.17858831070003318849.stgit@noble.brown> User-Agent: StGit/0.23 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org The bdi congestion tracking in not widely used and will be removed. Fuse is one of a small number of filesystems that uses it, setting both the sync (read) and async (write) congestion flags at what it determines are appropriate times. The only remaining effect of the sync flag is to cause read-ahead to be skipped. The only remaining effect of the async flag is to cause (some) WB_SYNC_NONE writes to be skipped. So instead of setting the flags, change: - .readahead to stop when it has submitted all non-async pages for read. - .writepages to do nothing if WB_SYNC_NONE and the flag would be set - .writepage to return AOP_WRITEPAGE_ACTIVATE if WB_SYNC_NONE and the flag would be 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) will further delay the next attempt at writeout. This might be a good thing. Signed-off-by: NeilBrown --- fs/fuse/control.c | 17 ----------------- fs/fuse/dev.c | 8 -------- fs/fuse/file.c | 17 +++++++++++++++++ 3 files changed, 17 insertions(+), 25 deletions(-) diff --git a/fs/fuse/control.c b/fs/fuse/control.c index 000d2e5627e9..7cede9a3bc96 100644 --- a/fs/fuse/control.c +++ b/fs/fuse/control.c @@ -164,7 +164,6 @@ static ssize_t fuse_conn_congestion_threshold_write(struct file *file, { unsigned val; struct fuse_conn *fc; - struct fuse_mount *fm; ssize_t ret; ret = fuse_conn_limit_write(file, buf, count, ppos, &val, @@ -178,22 +177,6 @@ static ssize_t fuse_conn_congestion_threshold_write(struct file *file, down_read(&fc->killsb); spin_lock(&fc->bg_lock); fc->congestion_threshold = val; - - /* - * Get any fuse_mount belonging to this fuse_conn; s_bdi is - * shared between all of them - */ - - if (!list_empty(&fc->mounts)) { - fm = list_first_entry(&fc->mounts, struct fuse_mount, fc_entry); - if (fc->num_background < fc->congestion_threshold) { - clear_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC); - clear_bdi_congested(fm->sb->s_bdi, BLK_RW_ASYNC); - } else { - set_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC); - set_bdi_congested(fm->sb->s_bdi, BLK_RW_ASYNC); - } - } spin_unlock(&fc->bg_lock); up_read(&fc->killsb); fuse_conn_put(fc); diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index cd54a529460d..e1b4a846c90d 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -315,10 +315,6 @@ void fuse_request_end(struct fuse_req *req) wake_up(&fc->blocked_waitq); } - if (fc->num_background == fc->congestion_threshold && fm->sb) { - clear_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC); - clear_bdi_congested(fm->sb->s_bdi, BLK_RW_ASYNC); - } fc->num_background--; fc->active_background--; flush_bg_queue(fc); @@ -540,10 +536,6 @@ static bool fuse_request_queue_background(struct fuse_req *req) fc->num_background++; if (fc->num_background == fc->max_background) fc->blocked = 1; - if (fc->num_background == fc->congestion_threshold && fm->sb) { - set_bdi_congested(fm->sb->s_bdi, BLK_RW_SYNC); - set_bdi_congested(fm->sb->s_bdi, BLK_RW_ASYNC); - } list_add_tail(&req->list, &fc->bg_queue); flush_bg_queue(fc); queued = true; diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 829094451774..94747bac3489 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -966,6 +966,14 @@ static void fuse_readahead(struct readahead_control *rac) struct fuse_io_args *ia; struct fuse_args_pages *ap; + if (fc->num_background >= fc->congestion_threshold && + rac->ra->async_size >= readahead_count(rac)) + /* + * Congested and only async pages left, so skip the + * rest. + */ + break; + nr_pages = readahead_count(rac) - nr_pages; if (nr_pages > max_pages) nr_pages = max_pages; @@ -1958,6 +1966,7 @@ static int fuse_writepage_locked(struct page *page) static int fuse_writepage(struct page *page, struct writeback_control *wbc) { + struct fuse_conn *fc = get_fuse_conn(page->mapping->host); int err; if (fuse_page_is_writeback(page->mapping->host, page->index)) { @@ -1973,6 +1982,10 @@ static int fuse_writepage(struct page *page, struct writeback_control *wbc) return 0; } + if (wbc->sync_mode == WB_SYNC_NONE && + fc->num_background >= fc->congestion_threshold) + return AOP_WRITEPAGE_ACTIVATE; + err = fuse_writepage_locked(page); unlock_page(page); @@ -2226,6 +2239,10 @@ static int fuse_writepages(struct address_space *mapping, if (fuse_is_bad(inode)) goto out; + if (wbc->sync_mode == WB_SYNC_NONE && + fc->num_background >= fc->congestion_threshold) + return 0; + data.inode = inode; data.wpa = NULL; data.ff = NULL;