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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47763C54EE9 for ; Tue, 27 Sep 2022 22:05:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229960AbiI0WFW (ORCPT ); Tue, 27 Sep 2022 18:05:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229841AbiI0WFQ (ORCPT ); Tue, 27 Sep 2022 18:05:16 -0400 Received: from mail-qv1-xf2f.google.com (mail-qv1-xf2f.google.com [IPv6:2607:f8b0:4864:20::f2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B6AEDC117 for ; Tue, 27 Sep 2022 15:05:11 -0700 (PDT) Received: by mail-qv1-xf2f.google.com with SMTP id r14so195683qvn.3 for ; Tue, 27 Sep 2022 15:05:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=to:in-reply-to:cc:references:message-id:date:subject:mime-version :from:content-transfer-encoding:from:to:cc:subject:date; bh=vq4RzOkzG7OCiEJ/PQVxt+WO9NFG2Bbi2vogv+4OBXw=; b=W1QKdlrGiQtgu28/0OJ5gJsuKdyy3QoIvEEgskEtQJCjNnN4v+aKA1uHdzj1Nb3pSt p17MlIM5mBFLFCWwjeNSkdC1aEZMsqOi2NXp/1ttiHFE+Hmh/veL4xZJlm3/6mku2DgW 093Uu8u5c+caP0OWzaDAd9Zh7bZ87PO5dm4/I= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:in-reply-to:cc:references:message-id:date:subject:mime-version :from:content-transfer-encoding:x-gm-message-state:from:to:cc :subject:date; bh=vq4RzOkzG7OCiEJ/PQVxt+WO9NFG2Bbi2vogv+4OBXw=; b=Ub0edRfJAwJnel//pRoL0nLuJbVuUfUmNTPRAq5x8exoWCIS2lFrz4ciRwHpdppaG7 8clWJS63Ng87FwAMLwIr/0wfCmLdYbf7UubHyWgq955HOKDMAffDKvQVqjg61J+jirzf CzfIU8zw1lf6xXJWTqKGZncoKXLovTGzOenxIkUld8c34M032stqazPxM3oIGNrdR1vE +8hKGCZ0hQqo4SjdgS7+9aWvaQqZHr44fHOyt4ausUxgxe2P2jJIe4O/MjjGfpvMQjj3 XixOAC1bOpjvgbC5Xgu59Y3mSobVLvC/TRiZ0FJvzanFHRJIHa9PGlMQJHzqMGiReFR4 MrUw== X-Gm-Message-State: ACrzQf1p+GNaZ+TBNEtsdrAxQky1+xEZU1YPw2aCkp1BvGOoVsjlvhgl y8JjJdvMNYsvRKTH265ukXJ9jLrUiRHkcA== X-Google-Smtp-Source: AMsMyM6Pn+g5S4MD1kRfNzFYHOiQi1xY57/1QYAwQsvJdQ77F+a7XSytNuQp9a3VNWJTToV6HAlahA== X-Received: by 2002:a05:6214:2688:b0:4af:6573:c095 with SMTP id gm8-20020a056214268800b004af6573c095mr12199302qvb.106.1664316309927; Tue, 27 Sep 2022 15:05:09 -0700 (PDT) Received: from smtpclient.apple ([2600:1003:b116:b844:d431:b5b1:ec77:48cc]) by smtp.gmail.com with ESMTPSA id s13-20020ac8758d000000b003447c4f5aa5sm1633914qtq.24.2022.09.27.15.05.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 27 Sep 2022 15:05:09 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Joel Fernandes Mime-Version: 1.0 (1.0) Subject: Re: [PATCH v6 1/4] rcu: Make call_rcu() lazy to save power Date: Tue, 27 Sep 2022 18:05:08 -0400 Message-Id: <3F5B20A5-6E48-4603-ACBA-0A7947A9C457@joelfernandes.org> References: Cc: paulmck@kernel.org, rcu@vger.kernel.org, linux-kernel@vger.kernel.org, rushikesh.s.kadam@intel.com, neeraj.iitr10@gmail.com, frederic@kernel.org, rostedt@goodmis.org In-Reply-To: To: Uladzislau Rezki X-Mailer: iPhone Mail (19G82) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Sep 27, 2022, at 5:31 PM, Uladzislau Rezki wrote: >=20 > =EF=BB=BFOn Tue, Sep 27, 2022 at 05:13:34PM +0200, Uladzislau Rezki wrote:= >>> On Tue, Sep 27, 2022 at 04:59:44PM +0200, Uladzislau Rezki wrote: >>> On Tue, Sep 27, 2022 at 02:30:03PM +0000, Joel Fernandes wrote: >>>> On Tue, Sep 27, 2022 at 04:08:18PM +0200, Uladzislau Rezki wrote: >>>>> On Mon, Sep 26, 2022 at 08:54:27PM +0000, Joel Fernandes wrote: >>>>>> Hi Vlad, >>>>>>=20 >>>>>> On Mon, Sep 26, 2022 at 09:39:23PM +0200, Uladzislau Rezki wrote: >>>>>> [...] >>>>>>>>> On my KVM machine the boot time is affected: >>>>>>>>>=20 >>>>>>>>> >>>>>>>>> [ 2.273406] e1000 0000:00:03.0 eth0: Intel(R) PRO/1000 Network C= onnection >>>>>>>>> [ 11.945283] e1000 0000:00:03.0 ens3: renamed from eth0 >>>>>>>>> [ 22.165198] sr 1:0:0:0: [sr0] scsi3-mmc drive: 4x/4x cd/rw xa/f= orm2 tray >>>>>>>>> [ 22.165206] cdrom: Uniform CD-ROM driver Revision: 3.20 >>>>>>>>> [ 32.406981] sr 1:0:0:0: Attached scsi CD-ROM sr0 >>>>>>>>> [ 104.115418] process '/usr/bin/fstype' started with executable s= tack >>>>>>>>> [ 104.170142] EXT4-fs (sda1): mounted filesystem with ordered dat= a mode. Quota mode: none. >>>>>>>>> [ 104.340125] systemd[1]: systemd 241 running in system mode. (+P= AM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCR= YPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN -PCRE2 d= efault-hierarchy=3Dhybrid) >>>>>>>>> [ 104.340193] systemd[1]: Detected virtualization kvm. >>>>>>>>> [ 104.340196] systemd[1]: Detected architecture x86-64. >>>>>>>>> [ 104.359032] systemd[1]: Set hostname to . >>>>>>>>> [ 105.740109] random: crng init done >>>>>>>>> [ 105.741267] systemd[1]: Reached target Remote File Systems. >>>>>>>>> >>>>>>>>>=20 >>>>>>>>> 2 - 11 and second delay is between 32 - 104. So there are still us= ers which must >>>>>>>>> be waiting for "RCU" in a sync way. >>>>>>>>=20 >>>>>>>> I was wondering if you can compare boot logs and see which timestam= p does the >>>>>>>> slow down start from. That way, we can narrow down the callback. Al= so another >>>>>>>> idea is, add "trace_event=3Drcu:rcu_callback,rcu:rcu_invoke_callbac= k >>>>>>>> ftrace_dump_on_oops" to the boot params, and then manually call >>>>>>>> "tracing_off(); panic();" from the code at the first printk that se= ems off in >>>>>>>> your comparison of good vs bad. For example, if "crng init done" ti= mestamp is >>>>>>>> off, put the "tracing_off(); panic();" there. Then grab the serial c= onsole >>>>>>>> output to see what were the last callbacks that was queued/invoked.= >>>>>>=20 >>>>>> Would you be willing to try these steps? Meanwhile I will try on my s= ide as >>>>>> well with the .config you sent me in another email. >>>>>>=20 >>>>> Not exactly those steps. But see below: >>>>>=20 >>>>> >>>>> [ 2.291319] e1000 0000:00:03.0 eth0: Intel(R) PRO/1000 Network Conn= ection >>>>> [ 17.302946] e1000 0000:00:03.0 ens3: renamed from eth0 >>>>> >>>>>=20 >>>>> 15 seconds delay between two prints. I have logged all call_rcu() user= s >>>>> between those two prints: >>>>>=20 >>>>> >>>>> # tracer: nop >>>>> # >>>>> # entries-in-buffer/entries-written: 166/166 #P:64 >>>>> # >>>>> # _-----=3D> irqs-off/BH-disabled >>>>> # / _----=3D> need-resched >>>>> # | / _---=3D> hardirq/softirq >>>>> # || / _--=3D> preempt-depth >>>>> # ||| / _-=3D> migrate-disable >>>>> # |||| / delay >>>>> # TASK-PID CPU# ||||| TIMESTAMP FUNCTION >>>>> # | | | ||||| | | >>>>> systemd-udevd-669 [002] ..... 2.338739: e1000_probe: Intel(R= ) PRO/1000 Network Connection >>>>> systemd-udevd-665 [061] ..... 2.338952: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 2.338962: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-665 [061] ..... 2.338965: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-645 [053] ..... 2.338968: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-665 [061] ..... 2.338987: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-645 [053] ..... 2.338989: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-645 [053] ..... 2.338999: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-645 [053] ..... 2.339002: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-645 [053] ..... 2.339024: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> kworker/0:3-546 [000] d..1. 6.329516: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70effe40a0 >>>>> rcuop/0-17 [000] b.... 6.337320: __call_rcu_common: -= > 0x0: exit_creds+0x63/0x70 <- 0x0 >>>>> kworker/38:1-744 [038] d..1. 6.841479: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f97e40a0 >>>>> <...>-739 [035] d..1. 6.841479: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f8be40a0 >>>>> <...>-732 [021] d..1. 6.841486: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f53e40a0 >>>>> kworker/36:1-740 [036] d..1. 6.841487: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f8fe40a0 >>>>> rcuop/21-170 [023] b.... 6.849276: __call_rcu_common: -= > 0x0: exit_creds+0x63/0x70 <- 0x0 >>>>> rcuop/38-291 [052] b.... 6.849950: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/38-291 [052] b.... 6.849957: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> kworker/5:1-712 [005] d..1. 7.097392: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f13e40a0 >>>>> kworker/19:1-727 [019] d..1. 7.097392: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f4be40a0 >>>>> <...>-719 [007] d..1. 7.097392: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f1be40a0 >>>>> kworker/13:1-721 [013] d..1. 7.097392: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f33e40a0 >>>>> kworker/52:1-756 [052] d..1. 7.097395: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fcfe40a0 >>>>> kworker/29:1-611 [029] d..1. 7.097395: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f73e40a0 >>>>> <...>-754 [049] d..1. 7.097405: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fc3e40a0 >>>>> kworker/12:1-726 [012] d..1. 7.097405: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f2fe40a0 >>>>> kworker/53:1-710 [053] d..1. 7.097405: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fd3e40a0 >>>>> <...>-762 [061] d..1. 7.097405: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70ff3e40a0 >>>>> <...>-757 [054] d..1. 7.097408: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fd7e40a0 >>>>> kworker/25:1-537 [025] d..1. 7.097408: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f63e40a0 >>>>> <...>-714 [004] d..1. 7.097408: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f0fe40a0 >>>>> <...>-749 [044] d..1. 7.097413: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fafe40a0 >>>>> kworker/51:1-755 [051] d..1. 7.097413: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fcbe40a0 >>>>> <...>-764 [063] d..1. 7.097415: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70ffbe40a0 >>>>> <...>-753 [045] d..1. 7.097416: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fb3e40a0 >>>>> kworker/43:1-748 [043] d..1. 7.097416: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fabe40a0 >>>>> kworker/41:1-747 [041] d..1. 7.097416: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fa3e40a0 >>>>> kworker/57:1-760 [057] d..1. 7.097416: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fe3e40a0 >>>>> <...>-720 [008] d..1. 7.097418: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f1fe40a0 >>>>> kworker/58:1-759 [058] d..1. 7.097421: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fe7e40a0 >>>>> kworker/16:1-728 [016] d..1. 7.097424: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f3fe40a0 >>>>> <...>-722 [010] d..1. 7.097427: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f27e40a0 >>>>> kworker/22:1-733 [022] d..1. 7.097432: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f57e40a0 >>>>> <...>-731 [026] d..1. 7.097432: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f67e40a0 >>>>> <...>-752 [048] d..1. 7.097437: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fbfe40a0 >>>>> kworker/18:0-147 [018] d..1. 7.097437: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f47e40a0 >>>>> kworker/39:1-745 [039] d..1. 7.097437: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f9be40a0 >>>>> <...>-716 [003] d..1. 7.097437: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70f0be40a0 >>>>> <...>-703 [050] d..1. 7.097437: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fc7e40a0 >>>>> kworker/42:1-746 [042] d..1. 7.097444: __call_rcu_common: -= > 0x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70fa7e40a0 >>>>> rcuop/13-113 [013] b.... 7.105592: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/13-113 [013] b.... 7.105595: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/10-92 [040] b.... 7.105608: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/10-92 [040] b.... 7.105610: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/16-135 [023] b.... 7.105613: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/8-78 [039] b.... 7.105636: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/8-78 [039] b.... 7.105640: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/12-106 [040] b.... 7.105651: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/12-106 [040] b.... 7.105652: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/19-156 [000] b.... 7.105727: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/19-156 [000] b.... 7.105730: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/5-56 [058] b.... 7.105808: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/5-56 [058] b.... 7.105814: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/20-163 [023] b.... 17.345648: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/20-163 [023] b.... 17.345655: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/14-120 [013] b.... 17.345675: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/14-120 [013] b.... 17.345681: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/6-63 [013] b.... 17.345714: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/6-63 [013] b.... 17.345715: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/9-85 [000] b.... 17.345753: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/9-85 [000] b.... 17.345758: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/17-142 [000] b.... 17.345775: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/17-142 [000] b.... 17.345776: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/17-142 [000] b.... 17.345777: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/11-99 [000] b.... 17.345810: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/11-99 [000] b.... 17.345811: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/15-127 [013] b.... 17.345832: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/15-127 [013] b.... 17.345834: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/1-28 [000] b.... 17.345834: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/1-28 [000] b.... 17.345835: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/15-127 [013] b.... 17.345835: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> rcuop/15-127 [013] b.... 17.345837: __call_rcu_common: -= > 0x0: file_free_rcu+0x32/0x50 <- 0x0 >>>>> systemd-udevd-633 [035] ..... 17.346591: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-633 [035] ..... 17.346609: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-633 [035] ..... 17.346659: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-633 [035] ..... 17.346666: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-669 [002] ..... 17.347573: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> kworker/2:2-769 [002] ..... 17.347659: __call_rcu_common: -= > 0x0: __wait_rcu_gp+0xff/0x120 <- 0x0 >>>>> systemd-udevd-675 [012] ..... 17.347981: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-675 [012] ..... 17.348002: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-675 [012] ..... 17.348037: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348098: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348117: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-665 [061] ..... 17.348120: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348156: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348166: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348176: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-642 [050] ..... 17.348179: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348186: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348197: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348200: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348231: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348240: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348250: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348259: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348262: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348305: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348317: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348332: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348336: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348394: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348403: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348406: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-645 [053] ..... 17.348503: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-645 [053] ..... 17.348531: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-645 [053] ..... 17.348535: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348536: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-645 [053] ..... 17.348563: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-665 [061] ..... 17.348575: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348628: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348704: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348828: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348884: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348904: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348954: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348983: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.348993: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349002: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349014: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349024: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349026: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349119: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349182: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349243: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349430: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349462: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349472: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349483: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349486: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349583: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349632: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349666: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349699: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-645 [053] ..... 17.349727: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349733: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-645 [053] ..... 17.349739: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-645 [053] ..... 17.349742: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349765: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-645 [053] ..... 17.349766: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-642 [050] ..... 17.349780: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-665 [061] ..... 17.349800: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-642 [050] ..... 17.349815: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-642 [050] ..... 17.349829: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-642 [050] ..... 17.349832: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349834: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-675 [012] ..... 17.349835: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-675 [012] ..... 17.349853: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-642 [050] ..... 17.349861: __call_rcu_common: -= > 0x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> systemd-udevd-675 [012] ..... 17.349873: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.349879: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.350007: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.350011: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.350080: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.350175: __call_rcu_common: -= > ____fput+0x0/0x10: task_work_run+0x5c/0x90 <- 0x0 >>>>> systemd-udevd-665 [061] ..... 17.350362: dev_change_name: -->= renamed from eth0 >>>>> >>>>>=20 >>>>> First delay: >>>>>=20 >>>>> >>>>> systemd-udevd-645 [053] ..... 2.339024: __call_rcu_common: -> 0= x0: __dentry_kill+0x140/0x180 <- 0x2 >>>>> kworker/0:3-546 [000] d..1. 6.329516: __call_rcu_common: -> 0= x0: queue_rcu_work+0x2b/0x40 <- 0xffff8c70effe40a0 >>>>> >>>>>=20 >>>>> __dentry_kill() function and after 4 seconds there is another one queu= e_rcu_work(). >>>>> I have checked the __dentry_kill() if it can do any sync talk with RCU= but from the >>>>> first glance i do not see anything critical. But more attention is req= uired. >>>>=20 >>>> Can you log rcu_barrier() as well? It could be that the print is just a= side >>>> effect of something else that is not being printed. >>>>=20 >>> It has nothing to do with rcu_barrier() in my case. Also i have checked >>> the synchronize_rcu() it also works as expected, i.e. it is not a >>> blocking reason. >>>=20 >>> Have you tried my config? >>>=20 >>> -- >>> Uladzislau Rezki >> OK. Seems one place i have spot: >>=20 >> >> [ 7.074847] calling init_sr+0x0/0x1000 [sr_mod] @ 668 >> [ 22.422808] sr 1:0:0:0: [sr0] scsi3-mmc drive: 4x/4x cd/rw xa/form2 tr= ay >> [ 22.422815] cdrom: Uniform CD-ROM driver Revision: 3.20 >> [ 32.664590] sr 1:0:0:0: Attached scsi CD-ROM sr0 >> [ 32.664642] initcall init_sr+0x0/0x1000 [sr_mod] returned 0 after 2558= 9786 usecs >> >>=20 >> -- >> Uladzislau Rezki >=20 > OK. Found the boot up issue. In my case i had 120 seconds delay: Wow, nice work. > > diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c > index 448748e3fba5..a56cfd612e3a 100644 > --- a/drivers/scsi/scsi_error.c > +++ b/drivers/scsi/scsi_error.c > @@ -312,7 +312,7 @@ void scsi_eh_scmd_add(struct scsi_cmnd *scmd) > * Ensure that all tasks observe the host state change before the > * host_failed change. > */ > - call_rcu(&scmd->rcu, scsi_eh_inc_host_failed); > + call_rcu_flush(&scmd->rcu, scsi_eh_inc_host_failed); Great! Thanks. I=E2=80=99ll include this and the other one you converted in t= he next revision. Thanks, - Joel=20 > } >=20 > /** > >=20 > After this change the boot-up time settles back to normal 4 seconds. >=20 > -- > Uladzislau Rezki