From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48jlMOhZe+lqYOf8uK0oJXBk1BTEt0sgx9vsNN+4WZjRn6YudZ18ziHf+XknfRa4Yr0iRTt ARC-Seal: i=1; a=rsa-sha256; t=1523624897; cv=none; d=google.com; s=arc-20160816; b=0R1xnzjM72sKnLZAsAosiWXzjVq5rZNie8mTD+kYdmQjU4eetX6n5FNPYbzRlXlt1u JNAoQmcoCKe7Uch5DohArNWSKkP40hjZ31IClFu4FgnY3EaBo0TRKx8t1BAazuYDobtC 26Sg+VfCbnpPxbxIgQ0KgMlWu1cr6Ng4KedEsHUqsLKnVemhqHcmVqZCEW9TIXKLy7Bt zp+xx8Mabh+9lKaZeCRnOBg+EBcGCYzhHFGk2WDITu7oy5H9uzzzi9Q5UTzlxEp0TDx1 QXqXN1QIbfpaRo6ogZ1qKW2C/H2dfuGz0pEB8izYYRfn6veb+3LgTOT66szP3uLyoywI 5YcA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=message-id:references:in-reply-to:date:subject:cc:to:from :arc-authentication-results; bh=XUCGLu7VgPhYFZjFy+Hh6t/oASScTF1JoyQKBHkEkdg=; b=LMHonX2Z4NHAWKkMNvAuFWMUR2NHwM9McRs5sDYeuJT4wUh8i/0klxbxf+6vUkdKQl +VIquSuUO7CEpFlrZAPMqYpYdlNENlTz9ok38Eg0HKh6Hg1HxsnTawSE/HWKJPyxQoML UJkk9nqNuc6SKjUx2v2u5D64/tkVHJ+OxUCqK3XpGqQx4h2UyB0xa07Km1Rj4Xito6y+ HGY859L0KRZbAFMPio/76/Lxxl0kp7fMWGuDrgLGO0VRlQsbSVEumFRcP1ARY8CCBUUZ 7M6j7m4dj003u+cwTeujkHFl2M3qtYbtvgbd5K/oPstepNZBXPsyH51PvanPCNntLsvU TRnA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of maier@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=maier@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of maier@linux.ibm.com designates 148.163.158.5 as permitted sender) smtp.mailfrom=maier@linux.ibm.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com From: Steffen Maier To: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Cc: Steven Rostedt , Ingo Molnar , Jens Axboe , Li Zefan , Greg Kroah-Hartman , Steffen Maier Subject: [PATCH 2/2] tracing/events: block: dev_t via driver core for plug and unplug events Date: Fri, 13 Apr 2018 15:07:18 +0200 X-Mailer: git-send-email 2.13.5 In-Reply-To: <20180413130719.22921-1-maier@linux.ibm.com> References: <20180413130719.22921-1-maier@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18041313-0044-0000-0000-00000546EEA6 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18041313-0045-0000-0000-000028872E75 Message-Id: <20180413130719.22921-3-maier@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-13_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804130122 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597636500726736984?= X-GMAIL-MSGID: =?utf-8?q?1597636500726736984?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Complements v2.6.31 commit 55782138e47d ("tracing/events: convert block trace points to TRACE_EVENT()") to be equivalent to traditional blktrace output. Also this allows event filtering to not always get all (un)plug events. NB: The NULL pointer check for q->kobj.parent is certainly racy and I don't have enough experience if it's good enough for a trace event. The change did work for my cases (block device read/write I/O on zfcp-attached SCSI disks and dm-mpath on top). While I haven't seen any prior art using driver core (parent) relations for trace events, there are other cases using this when no direct pointer exists between objects, such as: #define to_scsi_target(d) container_of(d, struct scsi_target, dev) static inline struct scsi_target *scsi_target(struct scsi_device *sdev) { return to_scsi_target(sdev->sdev_gendev.parent); } This is the object model we make use of here: struct gendisk { struct hd_struct { struct device { /*container_of*/ struct kobject kobj; <--+ dev_t devt; /*deref*/ | } __dev; | } part0; | struct request_queue *queue; ..+ | } : | : | struct request_queue { <..............+ | /* queue kobject */ | struct kobject { | struct kobject *parent; --------+ } kobj; } The parent pointer comes from: #define disk_to_dev(disk) (&(disk)->part0.__dev) int blk_register_queue(struct gendisk *disk) struct device *dev = disk_to_dev(disk); struct request_queue *q = disk->queue; ret = kobject_add(&q->kobj, kobject_get(&dev->kobj), "%s", "queue"); ^^^parent $ ls -d /sys/block/sdf/queue /sys/block/sda/queue $ cat /sys/block/sdf/dev 80:0 A partition does not have its own request queue: $ cat /sys/block/sdf/sdf1/dev 8:81 $ ls -d /sys/block/sdf/sdf1/queue ls: cannot access '/sys/block/sdf/sdf1/queue': No such file or directory The difference to blktrace parsed output is that block events don't use the partition's minor number but the containing block device's minor number: $ dd if=/dev/sdf1 count=1 $ cat /sys/kernel/debug/tracing/trace block_bio_remap: 8,80 R 2048 + 32 <- (8,81) 0 block_bio_queue: 8,80 R 2048 + 32 [dd] block_getrq: 8,80 R 2048 + 32 [dd] block_plug: 8,80 [dd] ^^^^ block_rq_insert: 8,80 R 16384 () 2048 + 32 [dd] block_unplug: 8,80 [dd] 1 explicit ^^^^ block_rq_issue: 8,80 R 16384 () 2048 + 32 [dd] block_rq_complete: 8,80 R () 2048 + 32 [0] $ btrace /dev/sdf1 8,80 1 1 0.000000000 240240 A R 2048 + 32 <- (8,81) 0 8,81 1 2 0.000220890 240240 Q R 2048 + 32 [dd] 8,81 1 3 0.000229639 240240 G R 2048 + 32 [dd] 8,81 1 4 0.000231805 240240 P N [dd] ^^ 8,81 1 5 0.000234671 240240 I R 2048 + 32 [dd] 8,81 1 6 0.000236365 240240 U N [dd] 1 ^^ 8,81 1 7 0.000238527 240240 D R 2048 + 32 [dd] 8,81 2 2 0.000613741 0 C R 2048 + 32 [0] Signed-off-by: Steffen Maier --- include/trace/events/block.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/include/trace/events/block.h b/include/trace/events/block.h index a13613d27cee..cffedc26e8a3 100644 --- a/include/trace/events/block.h +++ b/include/trace/events/block.h @@ -460,14 +460,18 @@ TRACE_EVENT(block_plug, TP_ARGS(q), TP_STRUCT__entry( + __field( dev_t, dev ) __array( char, comm, TASK_COMM_LEN ) ), TP_fast_assign( + __entry->dev = q->kobj.parent ? + container_of(q->kobj.parent, struct device, kobj)->devt : 0; memcpy(__entry->comm, current->comm, TASK_COMM_LEN); ), - TP_printk("[%s]", __entry->comm) + TP_printk("%d,%d [%s]", + MAJOR(__entry->dev), MINOR(__entry->dev), __entry->comm) ); #define show_block_unplug_explicit(val) \ @@ -482,18 +486,23 @@ DECLARE_EVENT_CLASS(block_unplug, TP_ARGS(q, depth, explicit), TP_STRUCT__entry( + __field( dev_t, dev ) __field( int, nr_rq ) __field( bool, explicit ) __array( char, comm, TASK_COMM_LEN ) ), TP_fast_assign( + __entry->dev = q->kobj.parent ? + container_of(q->kobj.parent, struct device, kobj)->devt : 0; __entry->nr_rq = depth; __entry->explicit = explicit; memcpy(__entry->comm, current->comm, TASK_COMM_LEN); ), - TP_printk("[%s] %d %s", __entry->comm, __entry->nr_rq, + TP_printk("%d,%d [%s] %d %s", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->comm, __entry->nr_rq, show_block_unplug_explicit(__entry->explicit)) ); -- 2.13.5