From patchwork Tue Jul 2 13:29:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 11027839 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3E107112C for ; Tue, 2 Jul 2019 13:24:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 25A08288AC for ; Tue, 2 Jul 2019 13:24:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 19C232890B; Tue, 2 Jul 2019 13:24:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8DC8628900 for ; Tue, 2 Jul 2019 13:24:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727077AbfGBNXw (ORCPT ); Tue, 2 Jul 2019 09:23:52 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:40950 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726963AbfGBNXw (ORCPT ); Tue, 2 Jul 2019 09:23:52 -0400 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 9252A2D5C714C1E33159; Tue, 2 Jul 2019 21:23:49 +0800 (CST) Received: from huawei.com (10.90.53.225) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.439.0; Tue, 2 Jul 2019 21:23:42 +0800 From: Hou Tao To: , CC: , , , , , , Subject: [RFC PATCH 2/3] md: export inflight io counters and internal stats in debugfs Date: Tue, 2 Jul 2019 21:29:17 +0800 Message-ID: <20190702132918.114818-3-houtao1@huawei.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190702132918.114818-1-houtao1@huawei.com> References: <20190702132918.114818-1-houtao1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.90.53.225] X-CFilter-Loop: Reflected Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There are so many io counters and stats/flags in md, so I think export these info in debugfs will be helpful for online-debugging, especially when the vmlinux and crash utility are not available. And these files can also be utilized during code understanding. Debug info are divided into two debugfs files: * iostat contains io counters and io related stats (e.g., mddev->pending_writes and the active status of mddev->sb_wait) * stat contains internal stats or flags (e.g., mddev->sb_flags) These two debugfs files will be created both by md-core and the used md-personality for each md device. This patch creates debug files for md-core under /sys/kernel/debug/block/mdX, and the following patch will creates these files for RAID1. The following lines show the hierarchy of debugfs files created for a RAID1 device: $ pwd /sys/kernel/debug/block/md0 $ tree . ├── iostat ├── raid1 │   ├── iostat │   └── stat └── stat Signed-off-by: Hou Tao --- drivers/md/md.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++++ drivers/md/md.h | 1 + 2 files changed, 66 insertions(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 9801d540fea1..dceb8fd59ba0 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -64,11 +64,14 @@ #include "md.h" #include "md-bitmap.h" #include "md-cluster.h" +#include "md-debugfs.h" #ifndef MODULE static void autostart_arrays(int part); #endif +extern struct dentry *blk_debugfs_root; + /* pers_list is a list of registered personalities protected * by pers_lock. * pers_lock does extra service to protect accesses to @@ -5191,6 +5194,65 @@ md_attr_store(struct kobject *kobj, struct attribute *attr, return rv; } +static int md_dbg_iostat_show(struct seq_file *m, void *data) +{ + struct mddev *mddev = m->private; + int active_bm_io = 0; + + spin_lock(&mddev->lock); + if (mddev->bitmap) + active_bm_io = atomic_read(&mddev->bitmap->pending_writes); + spin_unlock(&mddev->lock); + + seq_printf(m, "active_io %d\n", + atomic_read(&mddev->active_io)); + seq_printf(m, "sb_wait %d pending_writes %d\n", + waitqueue_active(&mddev->sb_wait), + atomic_read(&mddev->pending_writes)); + seq_printf(m, "recovery_active %d\n", + atomic_read(&mddev->recovery_active)); + seq_printf(m, "bitmap pending_writes %d\n", active_bm_io); + + return 0; +} + +static int md_dbg_stat_show(struct seq_file *m, void *data) +{ + struct mddev *mddev = m->private; + + seq_printf(m, "flags 0x%lx\n", mddev->flags); + seq_printf(m, "sb_flags 0x%lx\n", mddev->sb_flags); + seq_printf(m, "recovery 0x%lx\n", mddev->recovery); + + return 0; +} + +static const struct md_debugfs_file md_dbg_files[] = { + {.name = "iostat", .show = md_dbg_iostat_show}, + {.name = "stat", .show = md_dbg_stat_show}, + {}, +}; + +static void md_unregister_debugfs(struct mddev *mddev) +{ + debugfs_remove_recursive(mddev->debugfs_dir); +} + +static void md_register_debugfs(struct mddev *mddev) +{ + const char *name; + struct dentry *dir; + + name = kobject_name(&disk_to_dev(mddev->gendisk)->kobj); + dir = debugfs_create_dir(name, blk_debugfs_root); + if (!IS_ERR_OR_NULL(dir)) { + md_debugfs_create_files(dir, mddev, md_dbg_files); + mddev->debugfs_dir = dir; + } else { + mddev->debugfs_dir = NULL; + } +} + static void md_free(struct kobject *ko) { struct mddev *mddev = container_of(ko, struct mddev, kobj); @@ -5227,6 +5289,7 @@ static void mddev_delayed_delete(struct work_struct *ws) { struct mddev *mddev = container_of(ws, struct mddev, del_work); + md_unregister_debugfs(mddev); sysfs_remove_group(&mddev->kobj, &md_bitmap_group); kobject_del(&mddev->kobj); kobject_put(&mddev->kobj); @@ -5353,6 +5416,8 @@ static int md_alloc(dev_t dev, char *name) if (mddev->kobj.sd && sysfs_create_group(&mddev->kobj, &md_bitmap_group)) pr_debug("pointless warning\n"); + + md_register_debugfs(mddev); mutex_unlock(&mddev->open_mutex); abort: mutex_unlock(&disks_mutex); diff --git a/drivers/md/md.h b/drivers/md/md.h index 7c930c091193..e79ef2101c45 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -466,6 +466,7 @@ struct mddev { unsigned int good_device_nr; /* good device num within cluster raid */ bool has_superblocks:1; + struct dentry *debugfs_dir; }; enum recovery_flags {