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Date:   Fri, 4 Mar 2022 16:10:52 +0100
From:   Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To:     Tiezhu Yang <yangtiezhu@loongson.cn>
Cc:     Mike Rapoport <rppt@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Xuefeng Li <lixuefeng@loongson.cn>, linux-mips@vger.kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 1/4] MIPS: Refactor early_parse_mem() to fix mem=
 parameter
Message-ID: <20220304151052.GA27642@alpha.franken.de>
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On Tue, Mar 01, 2022 at 12:28:58PM +0800, Tiezhu Yang wrote:
> According to Documentation/admin-guide/kernel-parameters.txt,
> the kernel command-line parameter mem= means "Force usage of
> a specific amount of memory", but when add "mem=3G" to the
> command-line, kernel boot hangs in sparse_init().
> 
> This commit is similar with the implementation of the other
> archs such as arm64, powerpc and riscv, refactor the function
> early_parse_mem() and then use memblock_enforce_memory_limit()
> to limit the memory size.
> 
> With this patch, when add "mem=3G" to the command-line, the
> kernel boots successfully, we can see the following messages:

unfortunately this patch would break platforms without memory detection,
which simply use mem=32M for memory configuration. Not sure how many
rely on this mechanism. If we can make sure nobody uses it, I'm fine
with your patch.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]