slow boot with 7fef431be9c9 ("mm/page_alloc: place pages to tail in __free_pages_core()")

[Liang, Liang (Leo)]

[AMD Public Use]

Hi David,

root at scbu-Chachani:~# cat /proc/mtrr
reg00: base=0x000000000 (    0MB), size= 2048MB, count=1: write-back
reg01: base=0x0ffe00000 ( 4094MB), size=    2MB, count=1: write-protect
reg02: base=0x100000000 ( 4096MB), size=   16MB, count=1: write-protect
reg03: base=0x0ffde0000 ( 4093MB), size=  128KB, count=1: write-protect
reg04: base=0x0ff000000 ( 4080MB), size=  512KB, count=1: write-protect

BRs,
Leo
-----Original Message-----
From: David Hildenbrand <david at redhat.com> 
Sent: Tuesday, March 16, 2021 4:54 PM
To: Liang, Liang (Leo) <Liang.Liang at amd.com>; Mike Rapoport <rppt at linux.ibm.com>
Cc: Deucher, Alexander <Alexander.Deucher at amd.com>; linux-kernel at vger.kernel.org; amd-gfx list <amd-gfx at lists.freedesktop.org>; Andrew Morton <akpm at linux-foundation.org>; Huang, Ray <Ray.Huang at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>; Rafael J. Wysocki <rafael at kernel.org>; George Kennedy <george.kennedy at oracle.com>
Subject: Re: slow boot with 7fef431be9c9 ("mm/page_alloc: place pages to tail in __free_pages_core()")

On 16.03.21 09:43, Liang, Liang (Leo) wrote:
> [AMD Public Use]
> 
> Hi David,
> 
> Thanks for your explanation. We saw slow boot issue on our farm/QA's machines and mine. All of machines are same SoC/board.

I cannot spot anything really special in the logs -- it's just ordinary system ram -- except:

[    0.000027] MTRR fixed ranges enabled:
[    0.000028]   00000-9FFFF write-back
[    0.000029]   A0000-BFFFF uncachable
[    0.000030]   C0000-FFFFF write-through
[    0.000031] MTRR variable ranges enabled:
[    0.000032]   0 base 000000000000 mask FFFF80000000 write-back
[    0.000034]   1 base 0000FFE00000 mask FFFFFFE00000 write-protect
[    0.000035]   2 base 000100000000 mask FFFFFF000000 write-protect
[    0.000036]   3 base 0000FFDE0000 mask FFFFFFFE0000 write-protect
[    0.000038]   4 base 0000FF000000 mask FFFFFFF80000 write-protect
[    0.000039]   5 disabled
[    0.000039]   6 disabled
[    0.000040]   7 disabled

Not sure if "2 base 000100000000" indicates something nasty. Not sure how to interpret the masks.

Can you provide the output of "cat /proc/mtrr" ?

--
Thanks,

David / dhildenb