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 55F70C433EF for ; Mon, 13 Dec 2021 10:39:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242348AbhLMKjB (ORCPT ); Mon, 13 Dec 2021 05:39:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242696AbhLMKhF (ORCPT ); Mon, 13 Dec 2021 05:37:05 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E42C1C08ED73 for ; Mon, 13 Dec 2021 02:16:54 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id CB448B80EF8 for ; Mon, 13 Dec 2021 10:16:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FE96C34603; Mon, 13 Dec 2021 10:16:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1639390611; bh=Gk+YAvQIyZPrNgbmEpUPOCGtK//NO96ShlpauXfv+Vw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RXDwIAW7r0xMWgKWgF2Tt97gIEZXek4l/qk4GTVIkurthAJJS3txJxrMRjn1P75IG 1hox6kALdzvRtPIdFsYMACF3sdmHOr4VewgKZC7XOVX6MdyTgbTKY+nDZlucraz+L6 EtRk8DSq6nQhkt/LW3sAac6HyltnAyRqoBphwJ0CtGlxVG4OBjRy0YFSSyikYZgxrf ChEGHsKB62/FV8WqvWI/WXRLl/b3iK5fEPJubMywPSrrWkl2qE8odX0ESP+vYqzldE Hhzttp7nD46AXzyVIwqutKzwYaXeudf1xVxyOfMZ/A18ox6mfZnll4QxXk3jdBVwQm 7bvV7H52NsIYA== Date: Mon, 13 Dec 2021 19:16:47 +0900 From: Masami Hiramatsu To: Jeff Xie Cc: Steven Rostedt , Masami Hiramatsu , mingo@redhat.com, Tom Zanussi , linux-kernel@vger.kernel.org Subject: Re: [RFC][PATCH v6 0/5] trace: Introduce objtrace trigger to trace the kernel object Message-Id: <20211213191647.36d6016fb08420fbc6d55b1b@kernel.org> In-Reply-To: References: <20211129164951.220511-1-xiehuan09@gmail.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jeff, On Sat, 11 Dec 2021 00:55:31 +0800 Jeff Xie wrote: > hi Steve and Masami, > > I really don't know what else I can do to enhance this patchset, if > this idea is really valuable and > can play its role, it may need the help of you or other developers ;-) Thanks for ping me. Let me review it this week. Thank you! > > On Tue, Nov 30, 2021 at 12:50 AM Jeff Xie wrote: > > > > Introduce a method based on function tracer to trace any object and get > > the value of the object dynamically. the object can be obtained from the > > dynamic event (kprobe_event/uprobe_event) or the static event(tracepoint). > > > > Usage: > > When using the kprobe event, only need to set the objtrace(a new trigger), > > we can get the value of the object. The object is from the setting of the > > kprobe event. > > > > For example: > > For the function bio_add_page(): > > > > int bio_add_page(struct bio *bio, struct page *page, > > unsigned int len, unsigned int offset) > > > > Firstly, we can set the base of the object, thus the first string "arg1" > > stands for the value of the first parameter of this function bio_add_gage(), > > > > # echo 'p bio_add_page arg1=$arg1' >> ./kprobe_events > > > > Secondly, we can get the value dynamically base the above object. > > > > find the offset of the bi_size in struct bio: > > $ gdb vmlinux > > (gdb) p &(((struct bio *)0)->bi_iter.bi_size) > > $1 = (unsigned int *) 0x28 > > > > # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/ \ > > p_bio_add_page_0/trigger > > > > The best way to use this is that we can set the entrance event and exit > > event, for example, the following example is to set the read_papes as > > the entrance event, and set the __blk_account_io_start as the exit event. > > > > # cd /sys/kernel/debug/tracing/ > > # echo 0 > ./tracing_on > > # echo 'p read_pages' >> ./kprobe_events > > # echo 'p __blk_account_io_start' >> ./kprobe_events > > # echo 'traceon if comm == "cat"' > ./events/kprobes/p_read_pages_0/trigger > > # echo 'traceoff if comm == "cat"' > ./events/kprobes/p___blk_account_io_start_0/trigger > > # echo 'p bio_add_page arg1=$arg1' >> ./kprobe_events > > # echo 'objtrace:add:arg1,0x28:u32:1 if comm == "cat"' > ./events/kprobes/p_bio_add_page_0/trigger > > > > # du -sh /test.txt > > 12.0K /test.txt > > > > # cat /test.txt > /dev/null > > # cat ./trace > > > > # tracer: nop > > # > > # entries-in-buffer/entries-written: 50/50 #P:1 > > # > > # _-----=> irqs-off > > # / _----=> need-resched > > # | / _---=> hardirq/softirq > > # || / _--=> preempt-depth > > # ||| / _-=> migrate-disable > > # |||| / delay > > # TASK-PID CPU# ||||| TIMESTAMP FUNCTION > > # | | | ||||| | | > > cat-95 [000] ..... 1.412065: _raw_spin_unlock_irqrestore <-event_triggers_call object:0xffff888108af6328 value:0x0 > > cat-95 [000] ..... 1.412066: __bio_try_merge_page <-bio_add_page object:0xffff888108af6328 value:0x0 > > cat-95 [000] ..... 1.412066: __bio_add_page <-bio_add_page object:0xffff888108af6328 value:0x0 > > cat-95 [000] ..... 1.412066: rcu_read_unlock_strict <-xa_load object:0xffff888108af6328 value:0x1000 > > cat-95 [000] ..... 1.412066: bio_add_page <-ext4_mpage_readpages object:0xffff888108af6328 value:0x1000 > > cat-95 [000] ..... 1.412066: kprobe_ftrace_handler <-ftrace_ops_list_func object:0xffff888108af6328 value:0x1000 > > cat-95 [000] ..... 1.412067: get_kprobe <-kprobe_ftrace_handler object:0xffff888108af6328 value:0x1000 > > cat-95 [000] ..... 1.412067: __bio_try_merge_page <-bio_add_page object:0xffff888108af6328 value:0x1000 > > cat-95 [000] ..... 1.412067: __bio_add_page <-bio_add_page object:0xffff888108af6328 value:0x1000 > > cat-95 [000] ..... 1.412067: rcu_read_unlock_strict <-xa_load object:0xffff888108af6328 value:0x2000 > > cat-95 [000] ..... 1.412067: bio_add_page <-ext4_mpage_readpages object:0xffff888108af6328 value:0x2000 > > cat-95 [000] ..... 1.412067: kprobe_ftrace_handler <-ftrace_ops_list_func object:0xffff888108af6328 value:0x2000 > > cat-95 [000] ..... 1.412067: get_kprobe <-kprobe_ftrace_handler object:0xffff888108af6328 value:0x2000 > > cat-95 [000] ..... 1.412067: __bio_try_merge_page <-bio_add_page object:0xffff888108af6328 value:0x2000 > > cat-95 [000] ..... 1.412068: submit_bio <-ext4_mpage_readpages object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412068: submit_bio_noacct <-ext4_mpage_readpages object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412068: __submit_bio <-submit_bio_noacct object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412068: blk_try_enter_queue <-__submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412068: rcu_read_unlock_strict <-blk_try_enter_queue object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412068: rcu_read_unlock_strict <-blk_try_enter_queue object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412068: submit_bio_checks <-__submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412068: __cond_resched <-submit_bio_checks object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412068: rcu_all_qs <-__cond_resched object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412068: should_fail_bio <-submit_bio_checks object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412069: create_task_io_context <-submit_bio_checks object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412069: kmem_cache_alloc_node <-create_task_io_context object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412069: should_failslab <-kmem_cache_alloc_node object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412069: _raw_spin_lock <-create_task_io_context object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412069: blk_mq_submit_bio <-__submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412069: __blk_queue_split <-blk_mq_submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412069: bvec_split_segs <-__blk_queue_split object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412069: blk_attempt_plug_merge <-blk_mq_submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412070: __blk_mq_sched_bio_merge <-blk_mq_submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412070: dd_bio_merge <-blk_mq_submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412070: _raw_spin_lock <-dd_bio_merge object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412070: blk_mq_sched_try_merge <-dd_bio_merge object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412070: elv_merge <-blk_mq_sched_try_merge object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412070: elv_rqhash_find <-elv_merge object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412070: dd_request_merge <-blk_mq_sched_try_merge object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412070: elv_rb_find <-dd_request_merge object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412070: __blk_mq_alloc_request <-blk_mq_submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412071: dd_limit_depth <-__blk_mq_alloc_request object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412071: blk_mq_get_tag <-__blk_mq_alloc_request object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412071: __blk_mq_get_tag <-blk_mq_get_tag object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412071: blk_mq_rq_ctx_init.isra.0 <-blk_mq_submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412071: ktime_get <-blk_mq_rq_ctx_init.isra.0 object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412071: dd_prepare_request <-blk_mq_rq_ctx_init.isra.0 object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412071: __blk_account_io_start <-blk_mq_submit_bio object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412071: kprobe_ftrace_handler <-ftrace_ops_list_func object:0xffff888108af6328 value:0x3000 > > cat-95 [000] ..... 1.412071: get_kprobe <-kprobe_ftrace_handler object:0xffff888108af6328 value:0x3000 > > > > Jeff Xie (5): > > trace: Add trace any kernel object > > trace/objtrace: get the value of the object > > trace/README: Document objtrace trigger syntax > > trace/objtrace: Add testcases for objtrace > > trace/objtrace: Add documentation for objtrace > > > > Documentation/trace/events.rst | 114 +++ > > include/linux/trace_events.h | 1 + > > kernel/trace/Kconfig | 10 + > > kernel/trace/Makefile | 1 + > > kernel/trace/trace.c | 3 + > > kernel/trace/trace.h | 8 + > > kernel/trace/trace_entries.h | 18 + > > kernel/trace/trace_events_trigger.c | 1 + > > kernel/trace/trace_object.c | 660 ++++++++++++++++++ > > kernel/trace/trace_output.c | 40 ++ > > .../ftrace/test.d/trigger/trigger-objtrace.tc | 39 ++ > > 11 files changed, 895 insertions(+) > > create mode 100644 kernel/trace/trace_object.c > > create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-objtrace.tc > > > > -- > > 2.25.1 > > > > Thanks, > --- > JeffXie -- Masami Hiramatsu