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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7576DC43217 for ; Mon, 21 Nov 2022 08:33:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=G8CN4bwdXbqM2WOVbPwGoiZBUqRt2hEIaljmO0OQb3I=; b=hmmL70zJf8W5Wj nFlVD9N9d0E2nqrRlGR52gJegrtHAZCFScq4mJkLWpSdre3LW7xEjL7Fa9T6tESZ+G36H0vcZvVKb HzlXjgQ0WUYXfEZ9V/PpxmDfvWZmFIOP7rXzFl0zf42JSgVSPOEv9BqlQLgH1WxzhH41KiU2F9Cfy 3xkudCItm7njKoXTciRd/Z5WdHtx8FQa2wVclDHtdamo5kbPCwVQxK2J2lkqANCAfGAaZdC1l2N8C VDTfSaeekheXjsqGTKpoNIziFX6tm37LYYNelpk2ugjDhGAXKxHK3lU3PshECqhdl2QSjXzJtw+va sPIDifJZkAdlvqb3wZYA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ox2Da-00BI3L-1c; Mon, 21 Nov 2022 08:31:54 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ox2DR-00BI0G-Vk for linux-arm-kernel@lists.infradead.org; Mon, 21 Nov 2022 08:31:47 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669019503; 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: in-reply-to:in-reply-to:references:references; bh=lS+1v4t3MHKdnVMtm8dzAIaMzgKu70EAh1YPkpsaRUY=; b=K4NsOg0e5eV47dn75+Te0Dp1u/nIdzs5/8rNK5EFbTO3iwwukPudJM35S+vJAo62c+vGT3 WYvXmSghS3vs+TCwOa8bmEsFfbct2qTePuXfwYtoL9I1fJkxBz2eFKkL4af0sJEOLQTRIC QVv5yUeE+qq5vccZRt4iffKqrPnrFFA= 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-616-5tZ5hloXMymn1Pe7RqWmjg-1; Mon, 21 Nov 2022 03:31:40 -0500 X-MC-Unique: 5tZ5hloXMymn1Pe7RqWmjg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5F6B887B2A0; Mon, 21 Nov 2022 08:31:39 +0000 (UTC) Received: from localhost (ovpn-13-22.pek2.redhat.com [10.72.13.22]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CF436492CA2; Mon, 21 Nov 2022 08:31:37 +0000 (UTC) Date: Mon, 21 Nov 2022 16:31:32 +0800 From: Baoquan He To: Zhen Lei Cc: Dave Young , Vivek Goyal , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Jonathan Corbet , linux-doc@vger.kernel.org, "Eric W . Biederman" , Randy Dunlap , Feng Zhou , Kefeng Wang , Chen Zhou , John Donnelly , Dave Kleikamp Subject: Re: [PATCH v4 2/2] arm64: kdump: Support crashkernel=X fall back to reserve region above DMA zones Message-ID: References: <20221116121044.1690-1-thunder.leizhen@huawei.com> <20221116121044.1690-3-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221116121044.1690-3-thunder.leizhen@huawei.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221121_003146_132181_99CC4DEA X-CRM114-Status: GOOD ( 29.49 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 11/16/22 at 08:10pm, Zhen Lei wrote: > For crashkernel=X without '@offset', select a region within DMA zones > first, and fall back to reserve region above DMA zones. This allows > users to use the same configuration on multiple platforms. > > Signed-off-by: Zhen Lei > Acked-by: Baoquan He > --- > Documentation/admin-guide/kernel-parameters.txt | 2 +- > arch/arm64/mm/init.c | 17 ++++++++++++++++- > 2 files changed, 17 insertions(+), 2 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index a7b7147447b8bf8..ef6d922ed26b9dc 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -842,7 +842,7 @@ > memory region [offset, offset + size] for that kernel > image. If '@offset' is omitted, then a suitable offset > is selected automatically. > - [KNL, X86-64] Select a region under 4G first, and > + [KNL, X86-64, ARM64] Select a region under 4G first, and > fall back to reserve region above 4G when '@offset' > hasn't been specified. > See Documentation/admin-guide/kdump/kdump.rst for further details. > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index ba7227179822d10..58a0bb2c17f18cf 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -132,6 +132,7 @@ static void __init reserve_crashkernel(void) > unsigned long long crash_max = CRASH_ADDR_LOW_MAX; > char *cmdline = boot_command_line; > int ret; > + bool fixed_base = false; > > if (!IS_ENABLED(CONFIG_KEXEC_CORE)) > return; > @@ -163,12 +164,26 @@ static void __init reserve_crashkernel(void) > crash_size = PAGE_ALIGN(crash_size); > > /* User specifies base address explicitly. */ > - if (crash_base) > + if (crash_base) { > + fixed_base = true; > crash_max = crash_base + crash_size; > + } > > +retry: > crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, > crash_base, crash_max); This pachset looks good to me. While we observed a unexpected case, where a reserved region cross the high and low meomry region. I noticed Catalin has pointed that out. Even with the suggested code, we could have the kernel parameters like: crashkernel=512M,high crashkernel=128M,low, we finally have [4G-126M, 4G+386M], [1G, 1G+128M] regions in running kernel. This looks strange. I am wondering if we can specify explicit search_base in memblock_phys_alloc_range() to avoid above case. Like this, crashkernel,high region will only exist in high memory, crashkernel,low region only exists in low memory region. I made a draft patch based on this patchset to present what the code looks like. diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 58a0bb2c17f1..fd9d35e17a62 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -127,7 +127,7 @@ static int __init reserve_crashkernel_low(unsigned long long low_size) */ static void __init reserve_crashkernel(void) { - unsigned long long crash_base, crash_size; + unsigned long long crash_base, crash_size, search_base; unsigned long long crash_low_size = 0; unsigned long long crash_max = CRASH_ADDR_LOW_MAX; char *cmdline = boot_command_line; @@ -155,6 +155,7 @@ static void __init reserve_crashkernel(void) else if (ret) return; + search_base = CRASH_ADDR_LOW_MAX; crash_max = CRASH_ADDR_HIGH_MAX; } else if (ret || !crash_size) { /* The specified value is invalid */ @@ -166,12 +167,13 @@ static void __init reserve_crashkernel(void) /* User specifies base address explicitly. */ if (crash_base) { fixed_base = true; + search_base = crash_base; crash_max = crash_base + crash_size; } retry: crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, - crash_base, crash_max); + search_base, crash_max); if (!crash_base) { /* * If the first attempt was for low memory, fall back to @@ -180,6 +182,7 @@ static void __init reserve_crashkernel(void) */ if (!fixed_base && (crash_max == CRASH_ADDR_LOW_MAX)) { crash_max = CRASH_ADDR_HIGH_MAX; + search_base = CRASH_ADDR_LOW_MAX; crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE; goto retry; } @@ -189,7 +192,7 @@ static void __init reserve_crashkernel(void) return; } - if ((crash_base > CRASH_ADDR_LOW_MAX - crash_low_size) && + if ((crash_base > CRASH_ADDR_LOW_MAX) && crash_low_size && reserve_crashkernel_low(crash_low_size)) { memblock_phys_free(crash_base, crash_size); return; _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel