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From: Alex Ghiti <alex@ghiti.fr>
To: David Hildenbrand <david@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>, Arnd Bergmann <arnd@arndb.de>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	linux-doc@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
	linux-arch@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/3] Documentation: riscv: Add documentation that describes the VM layout
Date: Thu, 25 Feb 2021 06:56:11 -0500	[thread overview]
Message-ID: <7d9036d9-488b-47cc-4673-1b10c11baad0@ghiti.fr> (raw)
In-Reply-To: <5279e97c-3841-717c-2a16-c249a61573f9@redhat.com>

Le 2/25/21 à 5:34 AM, David Hildenbrand a écrit :
>                   |            |                  |         |> + 
> ffffffc000000000 | -256    GB | ffffffc7ffffffff |   32 GB | kasan
>> +   ffffffcefee00000 | -196    GB | ffffffcefeffffff |    2 MB | fixmap
>> +   ffffffceff000000 | -196    GB | ffffffceffffffff |   16 MB | PCI io
>> +   ffffffcf00000000 | -196    GB | ffffffcfffffffff |    4 GB | vmemmap
>> +   ffffffd000000000 | -192    GB | ffffffdfffffffff |   64 GB | 
>> vmalloc/ioremap space
>> +   ffffffe000000000 | -128    GB | ffffffff7fffffff |  126 GB | 
>> direct mapping of all physical memory
> 
> ^ So you could never ever have more than 126 GB, correct?
> 
> I assume that's nothing new.
> 

Before this patch, the limit was 128GB, so in my sense, there is nothing 
new. If ever we want to increase that limit, we'll just have to lower 
PAGE_OFFSET, there is still some unused virtual addresses after kasan 
for example.

Thanks,

Alex


  reply	other threads:[~2021-02-25 11:56 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-25  8:04 [PATCH 0/3] Move kernel mapping outside the linear mapping Alexandre Ghiti
2021-02-25  8:04 ` [PATCH 1/3] riscv: Move kernel mapping outside of " Alexandre Ghiti
2021-02-25  8:04 ` [PATCH 2/3] Documentation: riscv: Add documentation that describes the VM layout Alexandre Ghiti
2021-02-25 10:34   ` David Hildenbrand
2021-02-25 11:56     ` Alex Ghiti [this message]
2021-03-10 11:42       ` Arnd Bergmann
2021-03-10 19:12         ` Alex Ghiti
2021-03-11  8:42           ` Arnd Bergmann
2021-03-13  8:23             ` Alex Ghiti
2021-03-13 22:34               ` Arnd Bergmann
2021-02-25  8:04 ` [PATCH 3/3] riscv: Prepare ptdump for vm layout dynamic addresses Alexandre Ghiti
2021-03-10  2:54 ` [PATCH 0/3] Move kernel mapping outside the linear mapping Palmer Dabbelt
2021-03-13  9:26   ` Alex Ghiti
2021-03-17  5:05     ` Palmer Dabbelt
2021-03-20  8:48   ` Alex Ghiti

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