From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9069C2D0DC for ; Thu, 2 Jan 2020 10:13:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BFE8D21734 for ; Thu, 2 Jan 2020 10:13:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="ENRgEjVE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728028AbgABKNF (ORCPT ); Thu, 2 Jan 2020 05:13:05 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:42954 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727990AbgABKNE (ORCPT ); Thu, 2 Jan 2020 05:13:04 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 002AAmRH130466 for ; Thu, 2 Jan 2020 10:13:03 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : subject : date : message-id : in-reply-to : references; s=corp-2019-08-05; bh=oPelsfMcCkuTCh8JkSFXa4mMalucJ8DwROMJiGbtGhY=; b=ENRgEjVEGMmkCxZPdmwGJsLew1pU7Rjd4qgtWifqTuWrrbLnYUCsT1TQ9wdTABsYiUeh buNi33jOKg4TNovk/7lmCiZ7yOQlWaJsWjJddgsFdgPdWNnQEKp0nLtyKDvRGZ00pEC4 VkVVRAadrpsA3PH7j9VEZjaQOTKxGhosQ3bXmAz228nFY13t/+Vufu2VaaSV4BixeIcJ 33wOJSYf1tEmfWc0zsVGs+O23c5TZa3OefSNyfmgO6wGdwOPdMsUIyAlr6dd+y0KSwWi knS2zcqmjk0nGHi8hFrE1PO7/PrnNIsy5/jRhGpLp5Sn+WcIbvd7bfFmbs7mOKirSn2B BQ== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 2x5ypqpk27-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Thu, 02 Jan 2020 10:13:03 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 002A9KOl090707 for ; Thu, 2 Jan 2020 10:13:02 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3030.oracle.com with ESMTP id 2x8gjad5t7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Thu, 02 Jan 2020 10:13:02 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 002AD1me006577 for ; Thu, 2 Jan 2020 10:13:01 GMT Received: from tp.localdomain (/39.109.145.141) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 02 Jan 2020 02:13:01 -0800 From: Anand Jain To: linux-btrfs@vger.kernel.org Subject: [PATCH v2 1/3] btrfs: add readmirror type framework Date: Thu, 2 Jan 2020 18:12:46 +0800 Message-Id: <1577959968-19427-2-git-send-email-anand.jain@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1577959968-19427-1-git-send-email-anand.jain@oracle.com> References: <1577959968-19427-1-git-send-email-anand.jain@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9487 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=1 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001020092 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9487 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001020092 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org As of now we use %pid method to read stripped mirrored data. So application's process id determines the stripe id to be read. This type of read IO routing typically helps in a system with many small independent applications tying to read random data. On the other hand the %pid based read IO distribution policy is inefficient if there is a single application trying to read large data and the overall disk bandwidth remains under utilized. So this patch introduces a framework where we could add more readmirror policies, such as routing the IO based on device's wait-queue or manual when we have a read-preferred device or a policy based on the target storage caching. Signed-off-by: Anand Jain --- v2: Declare fs_devices::readmirror as u8 instead of atomic_t A small change in comment and change log wordings. fs/btrfs/volumes.c | 16 +++++++++++++++- fs/btrfs/volumes.h | 8 ++++++++ 2 files changed, 23 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index c95e47aa84f8..e26af766f2b9 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1162,6 +1162,8 @@ static int open_fs_devices(struct btrfs_fs_devices *fs_devices, fs_devices->opened = 1; fs_devices->latest_bdev = latest_dev->bdev; fs_devices->total_rw_bytes = 0; + /* Set the default readmirror policy */ + fs_devices->readmirror = BTRFS_READMIRROR_DEFAULT; out: return ret; } @@ -5300,7 +5302,19 @@ static int find_live_mirror(struct btrfs_fs_info *fs_info, else num_stripes = map->num_stripes; - preferred_mirror = first + current->pid % num_stripes; + switch (fs_info->fs_devices->readmirror) { + case BTRFS_READMIRROR_BY_PID: + preferred_mirror = first + current->pid % num_stripes; + break; + default: + /* + * Shouln't happen, just warn and use by_pid instead of failing. + */ + btrfs_warn_rl(fs_info, + "unknown readmirror type %u, fallback to by_pid", + fs_info->fs_devices->readmirror); + preferred_mirror = first + current->pid % num_stripes; + } if (dev_replace_is_ongoing && fs_info->dev_replace.cont_reading_from_srcdev_mode == diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 68021d1ee216..f5f091f3c72b 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -209,6 +209,12 @@ struct btrfs_device { BTRFS_DEVICE_GETSET_FUNCS(disk_total_bytes); BTRFS_DEVICE_GETSET_FUNCS(bytes_used); +/* readmirror_policy types */ +#define BTRFS_READMIRROR_DEFAULT BTRFS_READMIRROR_BY_PID +enum btrfs_readmirror_policy_type { + BTRFS_READMIRROR_BY_PID, +}; + struct btrfs_fs_devices { u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */ u8 metadata_uuid[BTRFS_FSID_SIZE]; @@ -260,6 +266,8 @@ struct btrfs_fs_devices { struct kobject *devices_kobj; struct kobject *devinfo_kobj; struct completion kobj_unregister; + + u8 readmirror; }; #define BTRFS_BIO_INLINE_CSUM_SIZE 64 -- 1.8.3.1