Allow to configure virtofsd's --thread-pool-size

Author: SuperSandro2000

nixos-modules/host/default.nix

@@ -281,7 +281,7 @@ in
               --socket-group=${config.users.users.microvm.group} \
               --shared-dir "$SOURCE" \
               --rlimit-nofile ${toString serviceConfig.LimitNOFILE} \
-              --thread-pool-size `nproc` \
+              --thread-pool-size ${toString config.microvm.virtiofsd.threadPoolSize} \
               --posix-acl --xattr \
               ${lib.optionalString (config.microvm.virtiofsd.inodeFileHandles != null)
                 "--inode-file-handles=${config.microvm.virtiofsd.inodeFileHandles}"

nixos-modules/host/options.nix

@@ -170,6 +170,15 @@
       '';
     };
 
+    virtiofsd.threadPoolSize = mkOption {
+      type = with types; oneOf [ str ints.unsigned ];
+      default = "`nproc`";
+      description = ''
+        The amounts of threads virtiofsd should spawn. This option also takes the special
+        string `\`nproc\`` which spawns as many threads as the host has cores.
+      '';
+    };
+
     virtiofsd.extraArgs = mkOption {
       type = with types; listOf str;
       default = [];