On Thu, Jan 28, 2021 at 2:08 PM Adam Williamson
<adamwill(a)fedoraproject.org> wrote:
On Thu, 2021-01-28 at 13:46 -0700, Chris Murphy wrote:
>
> OK I'm seeing this problem in a VM with
> Fedora-Workstation-Live-x86_64-Rawhide-20210128.n.0.iso but I'm not
> sure how consistent it is yet. MemTotal is ~3G for a VM that has 4G
> allocated. Something's wrong...
>
> VM 5.11.0-0.rc5.20210127git2ab38c17aac1.136.fc34.x86_64
> [ 0.701792] Memory: 3016992K/4190656K available (43019K kernel
> code, 11036K rwdata, 27184K rodata, 5036K init, 31780K bss, 1173408K
> reserved, 0K cma-reserved)
>
> Baremetal 5.10.11-200.fc33.x86_64
> [ 0.125875] Memory: 12059084K/12493424K available (14345K kernel
> code, 3465K rwdata, 9704K rodata, 2536K init, 5504K bss, 434080K
> reserved, 0K cma-reserved)
>
> Why is reserved so much higher in the VM case? It clearly sees the 4G
> but is delimiting it to 3G for some reason I don't understand. This is
> well before the zram module is loaded, by the way.
I've filed
https://bugzilla.redhat.com/show_bug.cgi?id=1921923 for
this. zdzichu suggests
https://lkml.org/lkml/2021/1/25/701 may be
related.
I'm not sure, because
Revert "mm: fix initialization of struct page for holes in memory layout"
landed in 5.10.11 and I wasn't have any of these memory related issues
with 5.10.10. I'm only seeing this so far with the debug kernels. Even
rc5 nodebug doesn't exhibit the problem.
--
Chris Murphy