lkml.org 
[lkml]   [2012]   [Jul]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: x86/mm: Limit 2/4M size calculation to x86_32
    On 07/24/2012 06:52 PM, Cong Wang wrote:

    >> From 6b679d1af20656929c0e829f29eed60b0a86a74f Mon Sep 17 00:00:00 2001
    >> From: Stefan Bader <stefan.bader@canonical.com>
    >> Date: Fri, 13 Jul 2012 15:16:33 +0200
    >> Subject: [PATCH] x86/mm: Limit 2/4M size calculation to x86_32
    >>
    >> commit 722bc6b (x86/mm: Fix the size calculation of mapping tables)
    >> did modify the extra space calculation for mapping tables in order
    >> to make up for the first 2/4M memory range using 4K pages.
    >> However this setup is only used when compiling for 32bit. On 64bit
    >> there is only the trailing area of 4K pages (which is already added).
    >>
    >> The code was already adapted once for things went wrong on a 8TB
    >> machine (bd2753b x86/mm: Only add extra pages count for the first memory
    >> range during pre-allocation early page table space), but it looks a bit
    >> like it currently would overdo things for 64bit.
    >> I only noticed while bisecting for the reason I could not make a crash
    >> kernel boot (which ended up on this patch).
    >>
    >> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
    >> Cc: WANG Cong <xiyou.wangcong@gmail.com>
    >> Cc: Yinghai Lu <yinghai@kernel.org>
    >> Cc: Tejun Heo <tj@kernel.org>
    >
    > Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
    >
    > Sorry for that I was not aware of x86_64 is different with x86 in the
    > first 2/4M.

    Why would there be a difference?

    Shouldn't the IO space at 0xa0000-0x100000 be mapped with uncacheable
    attributes (or WC for VGA)? If it's done later, it can be done later
    for both.

    --
    error compiling committee.c: too many arguments to function




    \
     
     \ /
      Last update: 2012-07-25 13:21    [W:3.115 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site