From: orca.chen@gmail.com (Min-Hua Chen)
To: kernelnewbies@lists.kernelnewbies.org
Subject: physical memory userspace/kernel split on Linux x86-64
Date: Wed, 27 May 2015 22:23:01 +0800 [thread overview]
Message-ID: <20150527142301.GA4358@debian777.Home> (raw)
In-Reply-To: <CACrq+iLS7cPyNb7qLKmQYdkZP2XcQ67ZtV7ne=PmBcCvwJ7VbQ@mail.gmail.com>
Hi,
Linux kernel basically manages all available physical memory pages.
If user-space need a page, kernel allocates a page for it. Hence a
physical page may be in mapped to user-space virtual address or
kernel-space virtual address or both.
The user-space and kernel-space exist in virtual address space, not
physical.
Thanks,
Min-Hua
On Wed, May 27, 2015 at 09:12:11AM +0800, Le Tan wrote:
> Hi,
> Is there an explict split between userspace and kernel in physical
> memory on Linux x86-64? That is, given a physical address, can I tell
> whether this address is from userspace or not?
> As far as I know, in virtual address space, the kernel will use the
> upper half and the userspace will use the lower half. But what about
> in physical address space?
>
> Thanks very much!
>
> Le
>
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> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
next prev parent reply other threads:[~2015-05-27 14:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-27 1:12 physical memory userspace/kernel split on Linux x86-64 Le Tan
2015-05-27 13:54 ` Karaoui mohamed lamine
2015-05-28 0:16 ` Le Tan
2015-05-27 14:23 ` Min-Hua Chen [this message]
2015-05-28 0:19 ` Le Tan
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