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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D17D1C433B4 for ; Fri, 7 May 2021 01:04:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF26B613B5 for ; Fri, 7 May 2021 01:04:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231271AbhEGBFm (ORCPT ); Thu, 6 May 2021 21:05:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:46330 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230384AbhEGBFl (ORCPT ); Thu, 6 May 2021 21:05:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 55A18613B9; Fri, 7 May 2021 01:04:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1620349482; bh=8sHBm7FVeCaTcPVAAlSZbcHtT9eMECCNvN6EiXYeKLw=; h=Date:From:To:Subject:In-Reply-To:From; b=KvJRbORTnItoP2ju+BjG5pz70TKzYBy6sBBjuznHX2XRzNYxVJFRUHCM8jWi0mWGy rzv8xnvM83Rbx+8vpdvh4s/6jbLcQK6vfkqagqtw6P1CF4cCek+FC0SCjG4DXQ9zKz Eb4o9IoAQnxUHbHOD01oxBR6WiWRVqF+obX1p+GM= Date: Thu, 06 May 2021 18:04:41 -0700 From: Andrew Morton To: akpm@linux-foundation.org, anton@enomsg.org, bhe@redhat.com, bhsharma@redhat.com, ccross@android.com, ebiederm@xmission.com, jmorris@namei.org, keescook@chromium.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, pasha.tatashin@soleen.com, pmladek@suse.com, sashal@kernel.org, tony.luck@intel.com, torvalds@linux-foundation.org, tyhicks@linux.microsoft.com Subject: [patch 51/91] kexec: dump kmessage before machine_kexec Message-ID: <20210507010441.lL4uYsEjV%akpm@linux-foundation.org> In-Reply-To: <20210506180126.03e1baee7ca52bedb6cc6003@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Pavel Tatashin Subject: kexec: dump kmessage before machine_kexec kmsg_dump(KMSG_DUMP_SHUTDOWN) is called before machine_restart(), machine_halt(), machine_power_off(), the only one that is missing is machine_kexec(). The dmesg output that it contains can be used to study the shutdown performance of both kernel and systemd during kexec reboot. Here is example of dmesg data collected after kexec: root@dplat-cp22:~# cat /sys/fs/pstore/dmesg-ramoops-0 | tail ... <6>[ 70.914592] psci: CPU3 killed (polled 0 ms) <5>[ 70.915705] CPU4: shutdown <6>[ 70.916643] psci: CPU4 killed (polled 4 ms) <5>[ 70.917715] CPU5: shutdown <6>[ 70.918725] psci: CPU5 killed (polled 0 ms) <5>[ 70.919704] CPU6: shutdown <6>[ 70.920726] psci: CPU6 killed (polled 4 ms) <5>[ 70.921642] CPU7: shutdown <6>[ 70.922650] psci: CPU7 killed (polled 0 ms) Link: https://lkml.kernel.org/r/20210319192326.146000-2-pasha.tatashin@soleen.com Signed-off-by: Pavel Tatashin Reviewed-by: Kees Cook Reviewed-by: Petr Mladek Reviewed-by: Bhupesh Sharma Acked-by: Baoquan He Reviewed-by: Tyler Hicks Cc: James Morris Cc: Sasha Levin Cc: Eric W. Biederman Cc: Anton Vorontsov Cc: Colin Cross Cc: Tony Luck Signed-off-by: Andrew Morton --- kernel/kexec_core.c | 2 ++ 1 file changed, 2 insertions(+) --- a/kernel/kexec_core.c~kexec-dump-kmessage-before-machine_kexec +++ a/kernel/kexec_core.c @@ -37,6 +37,7 @@ #include #include #include +#include #include #include @@ -1179,6 +1180,7 @@ int kernel_kexec(void) machine_shutdown(); } + kmsg_dump(KMSG_DUMP_SHUTDOWN); machine_kexec(kexec_image); #ifdef CONFIG_KEXEC_JUMP _