[pve-devel] [PATCH qemu-server 06/10] memory: use 64 slots && static dimm size with max is defined

[Fiona Ebner]

Am 09.12.22 um 20:27 schrieb Alexandre Derumier:
> default kernel vhost config only support 64 slots by default,
> for performance since 2015.
> 
> Original memory hotplug code was done before, using qemu
> max supported 255 slots.
> 
> To reach max mem (4TB), we used incremental dimm size.
> 
> Instead of dynamic memory size, use 1 static dimm size, compute
> from max memory/64.
> 
> Fix:
> https://bugzilla.proxmox.com/show_bug.cgi?id=3446
> https://bugzilla.proxmox.com/show_bug.cgi?id=1426
> Signed-off-by: Alexandre Derumier <aderumier at odiso.com>
> ---
>  PVE/QemuServer/Memory.pm | 31 ++++++++++++++++++++-----------
>  1 file changed, 20 insertions(+), 11 deletions(-)
> 
> diff --git a/PVE/QemuServer/Memory.pm b/PVE/QemuServer/Memory.pm
> index b847742..8bbbf07 100644
> --- a/PVE/QemuServer/Memory.pm
> +++ b/PVE/QemuServer/Memory.pm
> @@ -140,14 +140,15 @@ sub foreach_dimm{
>      my ($conf, $vmid, $memory, $sockets, $func) = @_;
>  
>      my $dimm_id = 0;
> -    my $current_size = 0;
> +    my $current_size = get_static_mem($conf);
>      my $dimm_size = 0;
>  
> -    if($conf->{hugepages} && $conf->{hugepages} == 1024) {
> -	$current_size = 1024 * $sockets;
> +    my $confmem = PVE::QemuServer::parse_memory($conf->{memory});
> +    if ($confmem->{max}) {
> +       $dimm_size = $confmem->{max}/64;

Style nit: missing spaces around division operator

> +    } elsif($conf->{hugepages} && $conf->{hugepages} == 1024) {
>  	$dimm_size = 1024;
>      } else {
> -	$current_size = 1024;
>  	$dimm_size = 512;
>      }
>  
> @@ -164,7 +165,7 @@ sub foreach_dimm{
>  	    &$func($conf, $vmid, $name, $dimm_size, $numanode, $current_size, $memory);
>  	    return  $current_size if $current_size >= $memory;
>  	}
> -	$dimm_size *= 2;
> +	$dimm_size *= 2 if !$confmem->{max};
>      }
>  }
>  
> @@ -175,7 +176,12 @@ sub foreach_reverse_dimm {
>      my $current_size = 0;
>      my $dimm_size = 0;
>  
> -    if($conf->{hugepages} && $conf->{hugepages} == 1024) {
> +    my $confmem = PVE::QemuServer::parse_memory($conf->{memory});
> +    if ($confmem->{max}) {
> +       $dimm_id = 63;
> +       $current_size = $confmem->{max};
> +       $dimm_size = $confmem->{max}/64;
> +    } elsif ($conf->{hugepages} && $conf->{hugepages} == 1024) {
>  	$current_size = 8355840;
>  	$dimm_size = 131072;
>      } else {
> @@ -197,6 +203,7 @@ sub foreach_reverse_dimm {
>  	    return  $current_size if $current_size <= $memory;
>  	}
>  	$dimm_size /= 2;

This line should be removed?

> +	$dimm_size /= 2 if !$confmem->{max};
>      }
>  }
>  
> @@ -263,7 +270,7 @@ sub qemu_memory_hotplug {
>  		    die $err;
>  		}
>  		#update conf after each succesful module hotplug
> -		my $mem = {};
> +		my $mem = { max => $MAX_MEM };
>  		$mem->{current} = $current_size;
>  		$conf->{memory} = PVE::QemuServer::print_memory($mem);
>  		PVE::QemuConfig->write_config($vmid, $conf);
> @@ -289,7 +296,7 @@ sub qemu_memory_hotplug {
>  		}
>  
>  		#update conf after each succesful module unplug
> -		my $mem = {};
> +		my $mem = { max => $MAX_MEM };
>  		$mem->{current} = $current_size;
>  		$conf->{memory} = PVE::QemuServer::print_memory($mem);
>  
> @@ -322,8 +329,9 @@ sub config {
>      my $memory = get_current_memory($conf);
>  
>      my $static_memory = get_static_mem($conf);
> +    my $confmem = PVE::QemuServer::parse_memory($conf->{memory});
>  
> -    if ($hotplug_features->{memory}) {
> +    if ($hotplug_features->{memory} || defined($confmem->{max})) {

So setting 'max' auto-attches the dimms[0], but without memory hotplug
enabled, those are useless? Or am I missing something? I feel like we
can just keep the conditional here and below[0] as-is.

>  	die "NUMA needs to be enabled for memory hotplug\n" if !$conf->{numa};
>  	my $MAX_MEM = get_max_mem($conf);
>  	die "Total memory is bigger than ${MAX_MEM}MB\n" if $memory > $MAX_MEM;
> @@ -334,7 +342,8 @@ sub config {
>  	}
>  
>  	die "minimum memory must be ${static_memory}MB\n" if($memory < $static_memory);
> -	push @$cmd, '-m', "size=${static_memory},slots=255,maxmem=${MAX_MEM}M";
> +	my $slots = $confmem->{max} ? 64 : 255;
> +	push @$cmd, '-m', "size=${static_memory},slots=$slots,maxmem=${MAX_MEM}M";
>  
>      } else {
>  	push @$cmd, '-m', $static_memory;
> @@ -403,7 +412,7 @@ sub config {
>  	}
>      }
>  
> -    if ($hotplug_features->{memory}) {
> +    if ($hotplug_features->{memory} || $confmem->{max}) {

[0]: here

>  	foreach_dimm($conf, $vmid, $memory, $sockets, sub {
>  	    my ($conf, $vmid, $name, $dimm_size, $numanode, $current_size, $memory) = @_;
>