From: Kars de Jong <karsdejong@home.nl>
To: Mike Rapoport <rppt@linux.ibm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Randy Dunlap <rdunlap@infradead.org>,
linux-m68k <linux-m68k@lists.linux-m68k.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: m68k Kconfig warning
Date: Wed, 4 Dec 2019 12:58:59 +0100 [thread overview]
Message-ID: <CACz-3riEr_HFAxQV8aorSqSwCyX9ZutwUqRR0qK8DuWg8ZWsJg@mail.gmail.com> (raw)
In-Reply-To: <20191202160101.GB17203@linux.ibm.com>
Hi Mike!
Op ma 2 dec. 2019 om 17:01 schreef Mike Rapoport <rppt@linux.ibm.com>:
> The patches are here:
> https://www.spinics.net/lists/linux-m68k/msg13588.html
>
> Aside from some technicalities we had troubles deciding what should be the
> section size. With larger section size we might end up with wasted memory
> for memory maps and with smaller section size we'll have to limit the
> addressable physical memory...
I read through that thread. I believe our current page->flags needs 22
bits for the normal FLAGS and 2 bits for the ZONES, which leaves 8
bits for the SECTION. This is what Geert found out (it worked with
MAX_PHYSMEM_BITS = 30 and SECTION_SIZE_BITS = 22).
I think we can reduces ZONES to a single bit. We currently put all
memory in ZONE_DMA, so I think we might just as well put it in
ZONE_NORMAL and disable ZONE_DMA.
That would enable us to have 8 MB sections and use the full 32-bit
address space, correct? That may be a working compromise?
Kind regards,
Kars.
prev parent reply other threads:[~2019-12-04 11:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-27 1:27 m68k Kconfig warning Randy Dunlap
2019-11-27 7:12 ` Geert Uytterhoeven
2019-12-02 11:42 ` Kars de Jong
2019-12-02 13:32 ` Geert Uytterhoeven
2019-12-02 16:01 ` Mike Rapoport
2019-12-04 11:58 ` Kars de Jong [this message]
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