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[23.128.96.18]) by mx.google.com with ESMTP id c3si3669439ejm.314.2020.08.06.09.29.55; Thu, 06 Aug 2020 09:30:18 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=fzkzyegv; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727103AbgHFQ2s (ORCPT + 99 others); Thu, 6 Aug 2020 12:28:48 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:52889 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727977AbgHFQSp (ORCPT ); Thu, 6 Aug 2020 12:18:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596730669; 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=tvRZphwGLcKXWF0F9sTs95B5v17a5GMwIlyltTlNMcU=; b=fzkzyegvVUwNy2qYUChW6AtI83fl/hZonENCGf+kPzU5S1NVyVGrMvzCO+ZrM3CGDytMVN 6PiRCz4o7/ZXJ/8sQ4nIsdCuYdpReDOMcZdCDEos6GB+YOMXh2u/6xPQTXRqLtTe3gA5BI W9SyxJRIcoBnstGsdCkRSRNyOK3IgCc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-227-OZxF1WYZN6-uEj33VNIDqQ-1; Thu, 06 Aug 2020 07:38:05 -0400 X-MC-Unique: OZxF1WYZN6-uEj33VNIDqQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 866391B18BC0; Thu, 6 Aug 2020 11:38:02 +0000 (UTC) Received: from dhcp-128-65.nay.redhat.com (ovpn-12-96.pek2.redhat.com [10.72.12.96]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6F65119C4F; Thu, 6 Aug 2020 11:37:53 +0000 (UTC) Date: Thu, 6 Aug 2020 19:37:50 +0800 From: Dave Young To: Chen Zhou Cc: catalin.marinas@arm.com, will@kernel.org, james.morse@arm.com, tglx@linutronix.de, mingo@redhat.com, bhe@redhat.com, corbet@lwn.net, John.P.donnelly@oracle.com, prabhakar.pkin@gmail.com, bhsharma@redhat.com, wangkefeng.wang@huawei.com, arnd@arndb.de, linux-doc@vger.kernel.org, xiexiuqi@huawei.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, horms@verge.net.au, nsaenzjulienne@suse.de, huawei.libin@huawei.com, guohanjun@huawei.com, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v11 0/5] support reserving crashkernel above 4G on arm64 kdump Message-ID: <20200806113750.GB2492@dhcp-128-65.nay.redhat.com> References: <20200801130856.86625-1-chenzhou10@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200801130856.86625-1-chenzhou10@huawei.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chen, Thanks for the update. I was busy on other things, I will review your x86/common changes this weekend or early next week. On 08/01/20 at 09:08pm, Chen Zhou wrote: > There are following issues in arm64 kdump: > 1. We use crashkernel=X to reserve crashkernel below 4G, which > will fail when there is no enough low memory. > 2. If reserving crashkernel above 4G, in this case, crash dump > kernel will boot failure because there is no low memory available > for allocation. > 3. Since commit 1a8e1cef7603 ("arm64: use both ZONE_DMA and ZONE_DMA32"), > if the memory reserved for crash dump kernel falled in ZONE_DMA32, > the devices in crash dump kernel need to use ZONE_DMA will alloc > fail. > > To solve these issues, change the behavior of crashkernel=X. > crashkernel=X tries low allocation in ZONE_DMA, and fall back to > high allocation if it fails. > > If requized size X is too large and leads to very little free memory > in ZONE_DMA after low allocation, the system may not work normally. > So add a threshold and go for high allocation directly if the required > size is too large. The value of threshold is set as the half of > the low memory. > > If crash_base is outside ZONE_DMA, try to allocate at least 256M in > ZONE_DMA automatically. "crashkernel=Y,low" can be used to allocate > specified size low memory. > For non-RPi4 platforms, change ZONE_DMA memtioned above to ZONE_DMA32. > > When reserving crashkernel in high memory, some low memory is reserved > for crash dump kernel devices. So there may be two regions reserved for > crash dump kernel, one is below 4G, the other is above 4G. > In order to distinct from the high region and make no effect to the use > of existing kexec-tools, rename the low region as "Crash kernel (low)", > and pass the low region by reusing DT property > "linux,usable-memory-range". We made the low memory region as the last > range of "linux,usable-memory-range" to keep compatibility with existing > user-space and older kdump kernels. > > Besides, we need to modify kexec-tools: > arm64: support more than one crash kernel regions(see [1]) > > Another update is document about DT property 'linux,usable-memory-range': > schemas: update 'linux,usable-memory-range' node schema(see [2]) > > Changes since [v10] > - Reimplement crashkernel=X suggested by Catalin, Many thanks to Catalin. > > Changes since [v9] > - Patch 1 add Acked-by from Dave. > - Update patch 5 according to Dave's comments. > - Update chosen schema. > > Changes since [v8] > - Reuse DT property "linux,usable-memory-range". > Suggested by Rob, reuse DT property "linux,usable-memory-range" to pass the low > memory region. > - Fix kdump broken with ZONE_DMA reintroduced. > - Update chosen schema. > > Changes since [v7] > - Move x86 CRASH_ALIGN to 2M > Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M. > - Update Documentation/devicetree/bindings/chosen.txt. > Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt > suggested by Arnd. > - Add Tested-by from Jhon and pk. > > Changes since [v6] > - Fix build errors reported by kbuild test robot. > > Changes since [v5] > - Move reserve_crashkernel_low() into kernel/crash_core.c. > - Delete crashkernel=X,high. > - Modify crashkernel=X,low. > If crashkernel=X,low is specified simultaneously, reserve spcified size low > memory for crash kdump kernel devices firstly and then reserve memory above 4G. > In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then > pass to crash dump kernel by DT property "linux,low-memory-range". > - Update Documentation/admin-guide/kdump/kdump.rst. > > Changes since [v4] > - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike. > > Changes since [v3] > - Add memblock_cap_memory_ranges back for multiple ranges. > - Fix some compiling warnings. > > Changes since [v2] > - Split patch "arm64: kdump: support reserving crashkernel above 4G" as > two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate > patch. > > Changes since [v1]: > - Move common reserve_crashkernel_low() code into kernel/kexec_core.c. > - Remove memblock_cap_memory_ranges() i added in v1 and implement that > in fdt_enforce_memory_region(). > There are at most two crash kernel regions, for two crash kernel regions > case, we cap the memory range [min(regs[*].start), max(regs[*].end)] > and then remove the memory range in the middle. > > [1]: http://lists.infradead.org/pipermail/kexec/2020-June/020737.html > [2]: https://github.com/robherring/dt-schema/pull/19 > [v1]: https://lkml.org/lkml/2019/4/2/1174 > [v2]: https://lkml.org/lkml/2019/4/9/86 > [v3]: https://lkml.org/lkml/2019/4/9/306 > [v4]: https://lkml.org/lkml/2019/4/15/273 > [v5]: https://lkml.org/lkml/2019/5/6/1360 > [v6]: https://lkml.org/lkml/2019/8/30/142 > [v7]: https://lkml.org/lkml/2019/12/23/411 > [v8]: https://lkml.org/lkml/2020/5/21/213 > [v9]: https://lkml.org/lkml/2020/6/28/73 > [v10]: https://lkml.org/lkml/2020/7/2/1443 > > Chen Zhou (5): > arm64: kdump: add macro CRASH_ALIGN and CRASH_ADDR_LOW_MAX > x86: kdump: move reserve_crashkernel_low() into crash_core.c > arm64: kdump: reimplement crashkernel=X > arm64: kdump: add memory for devices by DT property > linux,usable-memory-range > kdump: update Documentation about crashkernel > > Documentation/admin-guide/kdump/kdump.rst | 21 +++- > .../admin-guide/kernel-parameters.txt | 11 ++- > arch/arm64/include/asm/kexec.h | 9 ++ > arch/arm64/include/asm/processor.h | 1 + > arch/arm64/kernel/setup.c | 8 +- > arch/arm64/mm/init.c | 99 +++++++++++++++---- > arch/x86/include/asm/kexec.h | 24 +++++ > arch/x86/kernel/setup.c | 86 ++-------------- > include/linux/crash_core.h | 3 + > include/linux/kexec.h | 2 - > kernel/crash_core.c | 74 ++++++++++++++ > kernel/kexec_core.c | 17 ---- > 12 files changed, 233 insertions(+), 122 deletions(-) > > -- > 2.20.1 > > > _______________________________________________ > kexec mailing list > kexec@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec >