From: "H. Peter Anvin" <hpa@zytor.com>
To: Thomas Gleixner <tglx@linutronix.de>, Minfei Huang <mnfhuang@gmail.com>
Cc: mingo@redhat.com, x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: Avoid overlap the fixmap area on i386
Date: Tue, 28 Oct 2014 10:24:08 -0700 [thread overview]
Message-ID: <544FD138.3030305@zytor.com> (raw)
In-Reply-To: <alpine.DEB.2.11.1410281159590.5308@nanos>
On 10/28/2014 04:06 AM, Thomas Gleixner wrote:
>>
>> The available address we can use is lower than FIXADDR_BOOT_START. So
>> We will set the kmap boundary below the FIXADDR_BOOT_START, if configure
>> the high memory.
>>
>> If we configure the high memory, the vmalloc reserve area should end
>> up to PKMAP_BASE, otherwise should end up to FIXADDR_BOOT_START.
>
> Which is not really a problem, because the FIXADDR_BOOT area is only
> used during boot for early_ioremap() and it's unused when ioremap() is
> functional. vmalloc becomes available after early boot so the
> FIXADDR_BOOT area is available for reuse.
>
Given the very limited address space available on i386, it would be
extremely undesirable to not reuse address space when possible.
-hpa
next prev parent reply other threads:[~2014-10-28 17:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-23 15:36 [PATCH] mm: Avoid overlap the fixmap area on i386 Minfei Huang
2014-10-28 11:06 ` Thomas Gleixner
2014-10-28 17:24 ` H. Peter Anvin [this message]
2014-10-28 17:29 ` Thomas Gleixner
2014-10-29 3:14 ` H. Peter Anvin
2014-10-29 4:30 ` Minfei Huang
2014-10-28 11:24 ` [tip:x86/mm] x86/mm: " tip-bot for Minfei Huang
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