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Date:   Fri, 7 Apr 2023 14:03:52 +0200
From:   Simon Horman <horms@kernel.org>
To:     Guo Ren <guoren@kernel.org>
Cc:     Chen Jiahao <chenjiahao16@huawei.com>,
        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, 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 v3 1/2] riscv: kdump: Implement
 crashkernel=X,[high,low]
Message-ID: <ZDAGqL6CZGrL499u@kernel.org>
References: <20230406220206.3067006-1-chenjiahao16@huawei.com>
 <20230406220206.3067006-2-chenjiahao16@huawei.com>
 <CAJF2gTRtj=-XONv3cMZFd+qCtqUQqYZo5Lv7cgQbkGKTB0j7yg@mail.gmail.com>
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On Fri, Apr 07, 2023 at 05:06:24PM +0800, Guo Ren wrote:
> On Thu, Apr 6, 2023 at 10:06 PM Chen Jiahao <chenjiahao16@huawei.com> 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".
> Asked-by: Guo Ren <guoren@kernel.org>

Perhaps 'Acked-by' :)