From patchwork Thu May 11 03:03:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiubo Li X-Patchwork-Id: 681996 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 69301C77B7D for ; Thu, 11 May 2023 03:05:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236313AbjEKDEv (ORCPT ); Wed, 10 May 2023 23:04:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230205AbjEKDEt (ORCPT ); Wed, 10 May 2023 23:04:49 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2ED81FEA for ; Wed, 10 May 2023 20:04:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683774244; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=q2qa7ZbGP9Gf/yZVzfZGVX1RubLWkiHMBaeceEOAiww=; b=gFmqNWmQP5/P2626dmkL+gVHnKS5EJENijiWgvKHc3x2EWQI8nUvMHme3711giyrVRuWD0 643NxQ5qztZnnfbo1/3FnU7lZatd3WBgV9m60u6j+0nxAFbic42xHpW2xMx3RngrN9nxsd mRJwIVuPRMOdt0UhLdBRzAydT/HjYIE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-231-wAsyl2g1MpmvwDkXw_qVWA-1; Wed, 10 May 2023 23:04:02 -0400 X-MC-Unique: wAsyl2g1MpmvwDkXw_qVWA-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 612963C0ED61; Thu, 11 May 2023 03:04:02 +0000 (UTC) Received: from li-a71a4dcc-35d1-11b2-a85c-951838863c8d.ibm.com.com (ovpn-12-156.pek2.redhat.com [10.72.12.156]) by smtp.corp.redhat.com (Postfix) with ESMTP id F3941492C13; Thu, 11 May 2023 03:03:58 +0000 (UTC) From: xiubli@redhat.com To: idryomov@gmail.com, ceph-devel@vger.kernel.org Cc: jlayton@kernel.org, vshankar@redhat.com, sehuww@mail.scut.edu.cn, Xiubo Li , stable@vger.kernel.org Subject: [PATCH v5 2/2] ceph: fix blindly expanding the readahead windows Date: Thu, 11 May 2023 11:03:35 +0800 Message-Id: <20230511030335.337094-3-xiubli@redhat.com> In-Reply-To: <20230511030335.337094-1-xiubli@redhat.com> References: <20230511030335.337094-1-xiubli@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org From: Xiubo Li Blindly expanding the readahead windows will cause unneccessary pagecache thrashing and also will introdue the network workload. We should disable expanding the windows if the readahead is disabled and also shouldn't expand the windows too much. Expanding forward firstly instead of expanding backward for possible sequential reads. Bound `rreq->len` to the actual file size to restore the previous page cache usage. The posix_fadvise may change the maximum size of a file readahead. Cc: stable@vger.kernel.org Fixes: 49870056005c ("ceph: convert ceph_readpages to ceph_readahead") URL: https://lore.kernel.org/ceph-devel/20230504082510.247-1-sehuww@mail.scut.edu.cn URL: https://www.spinics.net/lists/ceph-users/msg76183.html Cc: Hu Weiwen Signed-off-by: Xiubo Li --- fs/ceph/addr.c | 40 +++++++++++++++++++++++++++++++++------- 1 file changed, 33 insertions(+), 7 deletions(-) diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index db55fce13324..e1bf90059112 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -188,16 +188,42 @@ static void ceph_netfs_expand_readahead(struct netfs_io_request *rreq) struct inode *inode = rreq->inode; struct ceph_inode_info *ci = ceph_inode(inode); struct ceph_file_layout *lo = &ci->i_layout; + unsigned long max_pages = inode->i_sb->s_bdi->ra_pages; + loff_t end = rreq->start + rreq->len, new_end; + struct ceph_netfs_request_data *priv = rreq->netfs_priv; + unsigned long max_len; u32 blockoff; - u64 blockno; - /* Expand the start downward */ - blockno = div_u64_rem(rreq->start, lo->stripe_unit, &blockoff); - rreq->start = blockno * lo->stripe_unit; - rreq->len += blockoff; + if (priv) { + /* Readahead is disabled by posix_fadvise POSIX_FADV_RANDOM */ + if (priv->file_ra_disabled) + max_pages = 0; + else + max_pages = priv->file_ra_pages; + + } + + /* Readahead is disabled */ + if (!max_pages) + return; - /* Now, round up the length to the next block */ - rreq->len = roundup(rreq->len, lo->stripe_unit); + max_len = max_pages << PAGE_SHIFT; + + /* + * Try to expand the length forward by rounding up it to the next + * block, but do not exceed the file size, unless the original + * request already exceeds it. + */ + new_end = min(round_up(end, lo->stripe_unit), rreq->i_size); + if (new_end > end && new_end <= rreq->start + max_len) + rreq->len = new_end - rreq->start; + + /* Try to expand the start downward */ + div_u64_rem(rreq->start, lo->stripe_unit, &blockoff); + if (rreq->len + blockoff <= max_len) { + rreq->start -= blockoff; + rreq->len += blockoff; + } } static bool ceph_netfs_clamp_length(struct netfs_io_subrequest *subreq)