From nobody Mon Dec 29 18:28:29 2025 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 4B0ECC61DF4 for ; Fri, 24 Nov 2023 19:58:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232601AbjKXT6g (ORCPT ); Fri, 24 Nov 2023 14:58:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232995AbjKXT6W (ORCPT ); Fri, 24 Nov 2023 14:58:22 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D2E92172A for ; Fri, 24 Nov 2023 11:58:28 -0800 (PST) Received: from relay2.suse.de (unknown [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 476CF1FE8F; Fri, 24 Nov 2023 19:58:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1700855907; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to; bh=qGzEJ9/paLrY7yN9mHnVDrutfQTfMGd2dXLSP1MKgTo=; b=LQLyN4VFubhseBPaSDv3sIMpCKyboHj3200tSV7VZiT2UHjBEltrsuDHzL43nvNBiYZTTZ iwLzxf3sxhCN4ljw+PfEzCPGByK/j1R6NIZ3/KzzhiDFD60wm+UvbdJflOvhrQG3nb2UaD cCdbkHkYvxoS91LEfTeebcj0m6aE3mQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1700855907; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to; bh=qGzEJ9/paLrY7yN9mHnVDrutfQTfMGd2dXLSP1MKgTo=; b=6N1XaEBpIJeFMnj/coakTwo4OtVDr1qA17zfdgNfSB5diJTD0EwzWrvRhafTW9pU1Y0b7j HutLmei93GtJBKDw== Received: from localhost (dwarf.suse.cz [10.100.12.32]) by relay2.suse.de (Postfix) with ESMTP id 679982C145; Fri, 24 Nov 2023 19:58:25 +0000 (UTC) Date: Fri, 24 Nov 2023 20:58:25 +0100 From: Jiri Bohac To: Baoquan He , Vivek Goyal , Dave Young , kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, mhocko@suse.cz Subject: [PATCH 4/4] kdump, documentation: describe craskernel CMA reservation Message-ID: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Spamd-Bar: +++++++++++++ X-Rspamd-Server: rspamd1 X-Rspamd-Queue-Id: 476CF1FE8F Authentication-Results: smtp-out2.suse.de; dkim=none; dmarc=none; spf=pass (smtp-out2.suse.de: domain of jbohac@suse.cz designates 149.44.160.134 as permitted sender) smtp.mailfrom=jbohac@suse.cz X-Spamd-Result: default: False [13.49 / 50.00]; RDNS_NONE(1.00)[]; SPAMHAUS_XBL(0.00)[149.44.160.134:from]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip4:149.44.0.0/16:c]; RWL_MAILSPIKE_GOOD(-1.00)[149.44.160.134:from]; HFILTER_HELO_IP_A(1.00)[relay2.suse.de]; HFILTER_HELO_NORES_A_OR_MX(0.30)[relay2.suse.de]; RCPT_COUNT_FIVE(0.00)[6]; MID_RHS_MATCH_FROMTLD(0.00)[]; MX_GOOD(-0.01)[]; RCVD_NO_TLS_LAST(0.10)[]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(2.20)[]; MIME_TRACE(0.00)[0:+]; RDNS_DNSFAIL(0.00)[]; ARC_NA(0.00)[]; FROM_HAS_DN(0.00)[]; NEURAL_SPAM_SHORT(3.00)[1.000]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(1.20)[suse.cz]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; NEURAL_SPAM_LONG(3.50)[1.000]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.cz:email]; FUZZY_BLOCKED(0.00)[rspamd.com]; RCVD_COUNT_TWO(0.00)[2]; HFILTER_HOSTNAME_UNKNOWN(2.50)[] Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Describe the new crashkernel ",cma" suffix in Documentation/ --- Documentation/admin-guide/kdump/kdump.rst | 10 ++++++++++ Documentation/admin-guide/kernel-parameters.txt | 7 +++++++ 2 files changed, 17 insertions(+) diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admi= n-guide/kdump/kdump.rst index 5762e7477a0c..4ec08e5843dc 100644 --- a/Documentation/admin-guide/kdump/kdump.rst +++ b/Documentation/admin-guide/kdump/kdump.rst @@ -317,6 +317,16 @@ crashkernel syntax =20 crashkernel=3D0,low =20 +4) crashkernel=3Dsize,cma + + Reserves additional memory from CMA. A standard crashkernel reservation= , as + described above, is still needed, but can be just small enough to hold = the + kernel and initrd. All the memory the crash kernel needs for its runtim= e and + for running the kdump userspace processes can be provided by this CMA + reservation, re-using memory available to the production system's users= pace. + Because of this re-using, the CMA reservation should not be used if it's + intended to dump userspce memory. + Boot into System Kernel ----------------------- 1) Update the boot loader (such as grub, yaboot, or lilo) configuration diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index 65731b060e3f..ee9fc40a97fd 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -914,6 +914,13 @@ 0: to disable low allocation. It will be ignored when crashkernel=3DX,high is not used or memory reserved is below 4G. + crashkernel=3Dsize[KMG],cma + [KNL, X86] Reserve additional crash kernel memory from CMA. + This reservation is usable by the 1st system's userspace, + so this should not be used if dumping of userspace=20 + memory is intended. A standard crashkernel reservation,=20 + as described above, is still needed to hold the crash=20 + kernel and initrd.=20 =20 cryptomgr.notests [KNL] Disable crypto self-tests --=20 Jiri Bohac SUSE Labs, Prague, Czechia