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Date:   Tue, 11 Apr 2023 09:35:55 +0200
From:   Simon Horman <horms@kernel.org>
To:     Chen Jiahao <chenjiahao16@huawei.com>
Cc:     linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
        kexec@lists.infradead.org, linux-doc@vger.kernel.org,
        paul.walmsley@sifive.com, palmer@dabbelt.com,
        conor.dooley@microchip.com, guoren@kernel.org, heiko@sntech.de,
        bjorn@rivosinc.com, alex@ghiti.fr, akpm@linux-foundation.org,
        atishp@rivosinc.com, bhe@redhat.com, thunder.leizhen@huawei.com
Subject: Re: [PATCH -next v4 1/2] riscv: kdump: Implement
 crashkernel=X,[high,low]
Message-ID: <ZDUN2+WG3OKGN/oq@kernel.org>
References: <20230410130553.3226347-1-chenjiahao16@huawei.com>
 <20230410130553.3226347-2-chenjiahao16@huawei.com>
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On Mon, Apr 10, 2023 at 09:05:52PM +0800, Chen Jiahao wrote:
> On riscv, the current crash kernel allocation logic is trying to
> allocate within 32bit addressible memory region by default, if
> failed, try to allocate without 4G restriction.
> 
> In need of saving DMA zone memory while allocating a relatively large
> crash kernel region, allocating the reserved memory top down in
> high memory, without overlapping the DMA zone, is a mature solution.
> Here introduce the parameter option crashkernel=X,[high,low].
> 
> One can reserve the crash kernel from high memory above DMA zone range
> by explicitly passing "crashkernel=X,high"; or reserve a memory range
> below 4G with "crashkernel=X,low".
> 
> Signed-off-by: Chen Jiahao <chenjiahao16@huawei.com>
> Acked-by: Guo Ren <guoren@kernel.org>
> Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>

Reviewed-by: Simon Horman <horms@kernel.org>