From: Alexey Dobriyan <adobriyan@gmail.com>
To: "Ozan Çağlayan" <ozan@pardus.org.tr>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC] A simple way to determine if the kernel needs HIGHMEM64G to be able to use all the installed memory
Date: Sat, 7 Mar 2009 22:30:26 +0300 [thread overview]
Message-ID: <20090307193026.GA2165@x200.localdomain> (raw)
In-Reply-To: <49B254C6.8010507@pardus.org.tr>
On Sat, Mar 07, 2009 at 01:04:38PM +0200, Ozan Çağlayan wrote:
> When the installed memory size is >= 4GB, kernel drops some messages like
>
> Warning only 4GB of memory will be used
> You have to enable HIGHMEM64G.
>
> I checked that the message comes from arch/x86/init_32.c after checking
> max_pfn.
>
> I'm quite dumb about the internal structures of the kernel but, wouldn't it
> be possible to create a simple read-only sysfs object like kexec_loaded
> that will contain "1" when the kernel needs HIGHMEM64G to see all of the memory
> and "0" when it doesn't?
Why do you need a file? If kernel says to enable HIGHMEM64G, enable it.
> I think that it would be a nice facility for distribution kernels to detect
> the need for a PAE enabled 32-bit kernel by just reading some /sys/.. entry.
next prev parent reply other threads:[~2009-03-07 19:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-07 11:04 Ozan Çağlayan
2009-03-07 19:30 ` Alexey Dobriyan [this message]
2009-03-07 19:43 ` Ozan Çağlayan
2009-03-08 20:20 ` Andi Kleen
2009-03-09 13:42 ` [PATCH] x86: suggest running a 64bit kernel on LM capable machines with plenty memory Peter Zijlstra
2009-03-09 19:15 ` Andi Kleen
2009-03-10 9:37 ` Peter Zijlstra
2009-03-10 12:50 ` Andi Kleen
2009-03-10 13:21 ` Arjan van de Ven
2009-03-11 12:01 ` Peter Zijlstra
2009-03-11 12:38 ` Andi Kleen
2009-03-11 11:47 ` Ingo Molnar
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