From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: Enable CONFIG_COMPAT also for 64k page size
Date: Fri, 05 Dec 2014 13:24:49 +0100 [thread overview]
Message-ID: <2131163.V0fUaF9isN@wuerfel> (raw)
In-Reply-To: <20141205110507.GB28339@e104818-lin.cambridge.arm.com>
On Friday 05 December 2014 11:05:07 Catalin Marinas wrote:
>
> > Should we add support for 64k-pages in the arm32 kernel as well now?
>
> 32-bit LPAE doesn't support 64K pages but IIRC the classic MMU does
> (though I have to check whether it was optional). But it's not feasible
> to enable this in a 32-bit environment because of the memory wasted with
> large pages (on average 32KB per mapped file, possibly even more if you
> have lots of small files).
That sounds like a tradeoff that some users might be willing to make.
I remember that with ps3-linux, a lot of people wanted to enable 64k-pages
because the Cell processor has such a small number of TLB entries (256 or
1024), but Linux only has around 200MB of memory available. I believe
there are arm32 machines with more RAM and fewer TLBs.
Arnd
next prev parent reply other threads:[~2014-12-05 12:24 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-04 15:46 [PATCH] arm64: Enable CONFIG_COMPAT also for 64k page size Alexander Graf
2014-12-04 18:18 ` Laura Abbott
2014-12-04 18:20 ` Will Deacon
2014-12-04 23:37 ` Alexander Graf
2014-12-08 13:47 ` Michael Matz
2014-12-06 17:23 ` Alexander Graf
2014-12-08 10:10 ` Will Deacon
2014-12-08 10:47 ` Alexander Graf
2015-03-11 11:24 ` Alexander Graf
2015-03-11 12:43 ` Andreas Schwab
2015-03-11 12:47 ` Arnd Bergmann
2015-03-11 13:08 ` Alexander Graf
2015-03-11 13:35 ` Andreas Schwab
2015-03-11 13:51 ` Arnd Bergmann
2015-03-11 13:57 ` Andreas Schwab
2015-03-11 15:44 ` Alexander Graf
2015-03-11 16:09 ` Andreas Schwab
2015-03-11 18:11 ` Alexander Graf
2015-03-12 9:07 ` [PATCH] arm64: fix implementation of mmap2 compat syscall Andreas Schwab
2015-03-16 14:16 ` [PATCH] arm64: Enable CONFIG_COMPAT also for 64k page size Christopher Covington
2015-03-16 14:19 ` Arnd Bergmann
2014-12-04 21:15 ` Olof Johansson
2014-12-04 23:41 ` Alexander Graf
2014-12-04 23:48 ` Olof Johansson
2014-12-05 10:39 ` Arnd Bergmann
2014-12-05 11:05 ` Catalin Marinas
2014-12-05 12:24 ` Arnd Bergmann [this message]
2014-12-05 12:31 ` Catalin Marinas
2015-02-18 13:40 ` Christopher Covington
2014-12-05 12:06 ` Alexander Graf
2014-12-05 11:14 ` Catalin Marinas
2014-12-05 11:35 ` Will Deacon
2015-03-13 4:44 ` Jon Masters
2014-12-05 16:35 ` Liviu Dudau
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