From nobody Mon Sep 15 03:56:28 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 45A9DC6379F for ; Tue, 17 Jan 2023 03:50:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235536AbjAQDuq (ORCPT ); Mon, 16 Jan 2023 22:50:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235501AbjAQDuf (ORCPT ); Mon, 16 Jan 2023 22:50:35 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8F12E227A6 for ; Mon, 16 Jan 2023 19:49:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673927387; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Tq8BWi7KIMXK19sTfFEOHzGCHbw3j+yt4nwzlz7Cvoc=; b=dYKtc0ph2+IQw29dI1QR2keVO8rJAia7hkB7v10J6o+Kn7H0Z5UXzROAWVWspmeGrwU3eo 6ZNJWw3CHy1h5jB6Auu+NqneVPBTo148oY/jlkTaA9BCRdnCWnMaWYhYHFjj+C+uzmXZLc sX2qQFcaJeTlqUaR4YuhfNFx7UTTrOw= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-487-upN5m9UrNDW622U8L_BpjQ-1; Mon, 16 Jan 2023 22:49:41 -0500 X-MC-Unique: upN5m9UrNDW622U8L_BpjQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CA8EA101A52E; Tue, 17 Jan 2023 03:49:40 +0000 (UTC) Received: from fedora.redhat.com (ovpn-12-229.pek2.redhat.com [10.72.12.229]) by smtp.corp.redhat.com (Postfix) with ESMTP id D146A14171B8; Tue, 17 Jan 2023 03:49:35 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, thunder.leizhen@huawei.com, John.p.donnelly@oracle.com, wangkefeng.wang@huawei.com, Baoquan He Subject: [PATCH 2/2] arm64/kdump: add code comments for crashkernel reservation cases Date: Tue, 17 Jan 2023 11:49:21 +0800 Message-Id: <20230117034921.185150-3-bhe@redhat.com> In-Reply-To: <20230117034921.185150-1-bhe@redhat.com> References: <20230117034921.185150-1-bhe@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This will help understand codes on crashkernel reservations on arm64. Signed-off-by: Baoquan He --- arch/arm64/mm/init.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 26a05af2bfa8..f88ad17cb20d 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -177,6 +177,10 @@ static void __init reserve_crashkernel(void) crash_base =3D memblock_phys_alloc_range(crash_size, CRASH_ALIGN, search_base, crash_max); if (!crash_base) { + /* + * For crashkernel=3Dsize[KMG]@offset[KMG], print out failure + * message if can't reserve the specified region. + */ if (fixed_base) { pr_warn("cannot reserve crashkernel region [0x%llx-0x%llx]\n", search_base, crash_max); @@ -188,6 +192,11 @@ static void __init reserve_crashkernel(void) * high memory, the minimum required low memory will be * reserved later. */ + /* + * For crashkernel=3Dsize[KMG], if the first attempt was for + * low memory, fall back to high memory, the minimum required + * low memory will be reserved later. + */ if (!high && crash_max =3D=3D CRASH_ADDR_LOW_MAX) { crash_max =3D CRASH_ADDR_HIGH_MAX; search_base =3D CRASH_ADDR_LOW_MAX; @@ -195,6 +204,10 @@ static void __init reserve_crashkernel(void) goto retry; } =20 + /* + * For crashkernel=3Dsize[KMG],high, if the first attempt was for + * high memory, fall back to low memory. + */ if (high && (crash_max =3D=3D CRASH_ADDR_HIGH_MAX)) { crash_max =3D CRASH_ADDR_LOW_MAX; search_base =3D 0; --=20 2.34.1