Re: [PATCH qemu-server v2 2/11] fix #6370: virtiofs: add support for thread-pool-size option

["Daniel Kral" <d.kral@proxmox.com>]

On Mon Feb 23, 2026 at 4:39 PM CET, Markus Frank wrote:
> Allows tuning the number of worker threads used by virtiofsd.
>
> Signed-off-by: Markus Frank <m.frank@proxmox.com>
> ---
>  src/PVE/QemuServer/Virtiofs.pm | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/src/PVE/QemuServer/Virtiofs.pm b/src/PVE/QemuServer/Virtiofs.pm
> index b181db5f..cd95470d 100644
> --- a/src/PVE/QemuServer/Virtiofs.pm
> +++ b/src/PVE/QemuServer/Virtiofs.pm
> @@ -60,6 +60,14 @@ my $virtiofs_fmt = {
>          default => 0,
>          optional => 1,
>      },
> +    'thread-pool-size' => {
> +        type => 'integer',
> +        description => "Controls the maximum number of worker threads used by virtiofsd to"
> +            . " handle requests. A value of '0' disables the thread pool.",
> +        default => 0,
> +        minimum => 0,
> +        optional => 1,
> +    },
>  };
>  PVE::JSONSchema::register_format('pve-qm-virtiofs', $virtiofs_fmt);
>  
> @@ -180,6 +188,8 @@ sub start_virtiofsd {
>              my $cmd = [$virtiofsd_bin, "--fd=$fd", "--shared-dir=$path"];
>              push @$cmd, '--xattr' if $virtiofs->{'expose-xattr'};
>              push @$cmd, '--posix-acl' if $virtiofs->{'expose-acl'};
> +            push @$cmd, '--thread-pool-size=' . $virtiofs->{'thread-pool-size'}
> +                if $virtiofs->{'thread-pool-size'};

nit: this should be `if defined($virtiofs->{'thread-pool-size'})`,
     otherwise it will not add `--thread-pool-size` at all. This still
     works as expected because virtiofsd itself falls back to 0 though
     [0].

[0] https://gitlab.com/virtio-fs/virtiofsd/-/blob/89a24d1eb57d20b497c53a11cbf60a79b5655de4/src/main.rs#L156

>              push @$cmd, '--announce-submounts';
>              push @$cmd, '--allow-direct-io' if $virtiofs->{'direct-io'};
>              push @$cmd, '--cache=' . $virtiofs->{cache} if $virtiofs->{cache};