lkml.org 
[lkml]   [2024]   [Apr]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: riscv32 EXT4 splat, 6.8 regression?
On 2024-04-17 Theodore Ts'o wrote:
> On Wed, Apr 17, 2024 at 12:36:39AM +0200, Nam Cao wrote:
> >
> > However, I am confused about one thing: doesn't this make one page of
> > physical memory inaccessible?
>
> So are these riscv32 systems really having multiple terabytes of
> memory? Why is this page in the physical memory map in the first
> place?

It's 32 bit, so it doesn't take much to fill up the entire address space.

Here's the memory layout from kernel boot log:

[ 0.000000] Virtual kernel memory layout:
[ 0.000000] fixmap : 0x9c800000 - 0x9d000000 (8192 kB)
[ 0.000000] pci io : 0x9d000000 - 0x9e000000 ( 16 MB)
[ 0.000000] vmemmap : 0x9e000000 - 0xa0000000 ( 32 MB)
[ 0.000000] vmalloc : 0xa0000000 - 0xc0000000 ( 512 MB)
[ 0.000000] lowmem : 0xc0000000 - 0x00000000 (1024 MB)

Note that lowmem occupies the last 1GB, including ERR_PTR (the last
address wraps to zero)

Best regards,
Nam

\
 
 \ /
  Last update: 2024-04-17 20:06    [W:0.074 / U:0.796 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site