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From: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>
To: Christophe LEROY <christophe.leroy@c-s.fr>
Cc: "Jonathan Neuschäfer" <j.neuschaefer@gmx.net>,
	linuxppc-dev@lists.ozlabs.org, "Joel Stanley" <joel@jms.id.au>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 0/6] DISCONTIGMEM support for PPC32
Date: Thu, 22 Feb 2018 00:31:58 +0100	[thread overview]
Message-ID: <20180221233158.4rnxsyxffhevtj44@latitude> (raw)
In-Reply-To: <a36983ec-5e97-e968-8143-1b2615ea55f8@c-s.fr>

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On Wed, Feb 21, 2018 at 04:02:25PM +0100, Christophe LEROY wrote:
[...]
> > > My question might me stupid, as I don't know PCC64 in deep, but when looking
> > > at page_is_ram() in arch/powerpc/mm/mem.c, I have the feeling the PPC64
> > > implements ram by blocks. Isn't it what you are trying to achieve ? Wouldn't
> > > it be feasible to map to what's done in PPC64 for PPC32 ?
> > 
> > Using page_is_ram in __ioremap_caller and the same memblock-based
> > approach that's used on PPC64 on PPC32 *should* work, but I think due to
> > the following line in initmem_init, it won't:
> > 
> > 	memblock_set_node(0, (phys_addr_t)ULLONG_MAX, &memblock.memory, 0);
> 
> Can't we just fix that ?

Turns out I was completely wrong about this. memblock_set_node as called
above only assigns all memory to node 0 and merges *adjacent* memblocks.
It doesn't merge the memblocks on the Wii, which are far apart.

So now I actually have a working patchset (coming soon), that's a good
deal shorter than this patchset, and hopefully won't break
CONFIG_HIGHMEM in the same way.

Thanks for your input! :)


Jonathan Neuschäfer

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      parent reply	other threads:[~2018-02-21 23:32 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-20 16:14 [PATCH 0/6] DISCONTIGMEM support for PPC32 Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 1/6] powerpc/mm/32: Use pfn_valid to check if pointer is in RAM Jonathan Neuschäfer
2018-02-20 17:45   ` christophe leroy
2018-02-21 13:51     ` Jonathan Neuschäfer
2018-02-21 14:44       ` Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 2/6] powerpc: numa: Fix overshift on PPC32 Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 3/6] powerpc: numa: Use the right #ifdef guards around functions Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 4/6] powerpc: numa: Restrict fake NUMA enulation to CONFIG_NUMA systems Jonathan Neuschäfer
2018-02-20 16:14 ` [PATCH 5/6] powerpc: Implement DISCONTIGMEM and allow selection on PPC32 Jonathan Neuschäfer
2018-02-20 23:46   ` kbuild test robot
2018-02-21 16:08     ` Jonathan Neuschäfer
2018-02-21 17:53       ` christophe leroy
2018-02-20 16:14 ` [PATCH 6/6] powerpc: wii: Don't rely on reserved memory hack if DISCONTIGMEM is set Jonathan Neuschäfer
2018-02-21  7:06 ` [PATCH 0/6] DISCONTIGMEM support for PPC32 Christophe LEROY
2018-02-21 14:42   ` Jonathan Neuschäfer
2018-02-21 15:02     ` Christophe LEROY
2018-02-21 16:52       ` Jonathan Neuschäfer
2018-02-21 23:31       ` Jonathan Neuschäfer [this message]

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