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 54C8FC433EF for ; Fri, 10 Dec 2021 16:55:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241072AbhLJQ7V (ORCPT ); Fri, 10 Dec 2021 11:59:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235352AbhLJQ7U (ORCPT ); Fri, 10 Dec 2021 11:59:20 -0500 Received: from mail-wr1-x436.google.com (mail-wr1-x436.google.com [IPv6:2a00:1450:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E92F0C061746 for ; Fri, 10 Dec 2021 08:55:44 -0800 (PST) Received: by mail-wr1-x436.google.com with SMTP id d24so16084347wra.0 for ; Fri, 10 Dec 2021 08:55:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=JPbyiTHSfKu4/qh4nWMhC6tllXbBA0PNxZRt/40TWPI=; b=UfF1KcCpRhsN+EAWF3Mxa+cfMV0Fs3LKGOOM3B7be1Y8jPCbfdoL0pCqqcxyoEe+Ws SNdtCmwSN+omZahLvGI9/hCTFoAuURGqXcJZI+zBzEEJJdA4VIAsyLVA9u0tjVB8p0Nm J8gE2DfTGZ3EUoxaXih+k1GAesbd95iYCkUa9f02QDmLOdMZx4JVWmLLza/84rZARubh zYQAgWQ7s4fGATmeH/3w9BOlPbPJWu5JR4Kw1rZmGK7bmPJkJQhNEF0+q9LNOpDbHE57 T0cYKssUpukVLMfk3Ti60halA7wFPZ4KMBQXQTThQ5gh0zHr8qfBas3G9qTa/8vwRNMG /pAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=JPbyiTHSfKu4/qh4nWMhC6tllXbBA0PNxZRt/40TWPI=; b=KORThT9qQmC/ep4iBQp5e3hPcuO7WdpOZZkPtNj+tmmD1HmHNuq4VojJPMtMBRmvdG pJxEHLkrxITvtS+N60ifq+/bovLu1C4FvQPFox4GV6qtll1hXZX+t3/0cFUlRXYliUzT DDNYclMJgFU/BkNARXzVoipukzQLEe1n8F1CcG9wUU1muiDh7wc7igEPsby9WEadmadw AM2yHazhRiSvZ7Pur4fpIV/+pxFKHFyOmtV+EQIHCm/j0Q9b4g0uEV1RMdLEfUxx7v6O pzzTgXdlsChJMz9mQZkX4qXtfEc56QRxmTZ9C+K3jTrKNi7cEeTGHNP1Balm5Lb8IMhR 9bIA== X-Gm-Message-State: AOAM533MPrJcPQQnsdIAsCNLHV2f7X4DtYaORbzmvKh2wx5d5iQbX3po YiIiV1x8u23HGyXB2TFutKArOiwCrXR7bT67kaop5HHvSfOfTA== X-Google-Smtp-Source: ABdhPJyTyulmbbUgIhuv6i8ZeMF9AcEBPKy2qPtQBXgFXUMzP0EbyS7v3GqyA+7WO3JVEX8Wo05+gFgyxufd594WS9U= X-Received: by 2002:a5d:6e82:: with SMTP id k2mr15085645wrz.147.1639155343553; Fri, 10 Dec 2021 08:55:43 -0800 (PST) MIME-Version: 1.0 References: <20211129164951.220511-1-xiehuan09@gmail.com> In-Reply-To: <20211129164951.220511-1-xiehuan09@gmail.com> From: Jeff Xie Date: Sat, 11 Dec 2021 00:55:31 +0800 Message-ID: Subject: Re: [RFC][PATCH v6 0/5] trace: Introduce objtrace trigger to trace the kernel object To: Steven Rostedt Cc: Masami Hiramatsu , mingo@redhat.com, Tom Zanussi , linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 ;-) 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