Re: [PVE-User] [pve-devel] [PATCH qemu-server 08/10] memory: add virtio-mem support

["DERUMIER, Alexandre" <Alexandre.DERUMIER@groupe-cyllene.com>]

Le mardi 20 décembre 2022 à 11:26 +0100, Fiona Ebner a écrit :
> Isn't ($MAX_MEM - $static_memory) / 32000 always strictly greater
> than
> 1? And if it could get smaller than 1, we also might have issues with
> the int()+1 approach, because the result of the first log() will
> become
> negative.
> 
> To be on the safe side we could just move the minimum check up:
> 
> my $blocksize = ($MAX_MEM - $static_memory) / 32000;
> $blocksize = 2 if $blocksize < 2;
> $blocksize = 2**(ceil(log($blocksize)/log(2)));

I think your are right.


I totally forget than mem was in bytes,

so the minimum blocksize is 2048


with a MAX_MEM of 64gb, the minimum blocksize is 2048.
(I remember now that I wanted 64GB minimum to have transparent huge
working out of the box).

if MAX_MEM was allowed 32gb ,the minimum blocksize with ceil is 1024.
so we need to force it to 2048

I'll rework the patch, thanks !