lkml.org 
[lkml]   [2007]   [Jun]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] trim memory not covered by WB MTRRs


On Tue, 12 Jun 2007, Pavel Machek wrote:

> Hi!
>
>>>> On some machines, buggy BIOSes don't properly setup WB MTRRs to
>>>> cover all available RAM, meaning the last few megs (or even gigs)
>>>> of memory will be marked uncached. Since Linux tends to allocate
>>>> from high memory addresses first, this causes the machine to be
>>>> unusably slow as soon as the kernel starts really using memory
>>>> (i.e. right around init time).
>>>>
>>>> + if ((highest_addr >> PAGE_SHIFT) != end_pfn) {
>>>> + printk(KERN_WARNING "***************\n");
>>>> + printk(KERN_WARNING "**** WARNING: likely BIOS bug\n");
>>>> + printk(KERN_WARNING "**** MTRRs don't cover all of "
>>>> + "memory, trimmed %ld pages\n", end_pfn -
>>>> + (highest_addr >> PAGE_SHIFT));
>>>> + printk(KERN_WARNING "***************\n");
>>>> + end_pfn = highest_addr >> PAGE_SHIFT;
>>>
>>> Missing 4K of memory is not worth 4K of junk in syslog per boot. Can
>>> you drop the stars and stop shouting?
>>
>> How missing about 1G of memory? We already discussed this, and Andi and
>> Venki felt that either a panic or a really obnoxious message was the
>> way to go...
>
> Just use panic, then.
> Pavel,
> who still thinks anyone missing 1GB of ram will not miss
> friendly notice in dmesg, even if it goes without 20 stars.
>
> --
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>

What is wrong with Jesse's patch? I've been using it for quite a few days
now, no issues.

Justin.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-06-12 23:35    [W:0.190 / U:1.908 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site