lkml.org 
[lkml]   [2008]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] [4/7] Don't use large pages to map the first 2/4MB of memory
Andi Kleen a écrit :
> Intel recommends to not use large pages for the first 1MB
> of the physical memory because there are fixed size MTRRs there
> which cause splitups in the TLBs.
>
> On AMD doing so is also a good idea.
>
> The implementation is a little different between 32bit and 64bit.
> On 32bit I just taught the initial page table set up about this
> because it was very simple to do. This also has the advantage
> that the risk of a prefetch ever seeing the page even
> if it only exists for a short time is minimized.
>
> On 64bit that is not quite possible, so use set_memory_4k() a little
> later (in check_bugs) instead.
>
> Signed-off-by: Andi Kleen <ak@suse.de>
>
> ---
> arch/x86/kernel/bugs_64.c | 12 ++++++++++++
> arch/x86/mm/init_32.c | 6 +++++-
> 2 files changed, 17 insertions(+), 1 deletion(-)
>

Should we then change CONFIG_PHYSICAL_START from 0x100000 to 0x400000 ?

Thank you
--
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: 2008-03-12 06:41    [W:0.143 / U:0.104 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site