3p/nixpkgs: add zram patch

third_party/nixpkgs/copy.bara.sky

@@ -15,7 +15,9 @@ core.workflow(
     ]),
     authoring = authoring.pass_thru("Default email <noreply+nixpkgs@lukegb.com>"),
     transformations = [
-        patch.apply(patches = []),
+        patch.apply(patches = [
+		"patches/0002-zram-allow-memorymax.patch",
+	]),
         core.move("", "third_party/nixpkgs"),
     ],
 )

third_party/nixpkgs/patches/0002-zram-allow-memorymax.patch

@@ -0,0 +1,33 @@
+diff --git a/nixos/modules/config/zram.nix b/nixos/modules/config/zram.nix
+--- a/nixos/modules/config/zram.nix
++++ b/nixos/modules/config/zram.nix
+@@ -80,6 +80,15 @@ in
+         '';
+       };
+ 
++      memoryMax = mkOption {
++        default = null;
++        type = with types; nullOr int;
++        description = ''
++          Maximum total amount of memory (in bytes) that can be used by the zram
++          swap devices.
++        '';
++      };
++
+       priority = mkOption {
+         default = 5;
+         type = types.int;
+@@ -146,7 +155,12 @@ in
+ 
+               # Calculate memory to use for zram
+               mem=$(${pkgs.gawk}/bin/awk '/MemTotal: / {
+-                  print int($2*${toString cfg.memoryPercent}/100.0/${toString devicesCount}*1024)
++                  value=int($2*${toString cfg.memoryPercent}/100.0/${toString devicesCount}*1024);
++                    ${if cfg.memoryMax != null then ''
++                      memory_max=int(${toString cfg.memoryMax}/${toString devicesCount});
++                      if (value > memory_max) { value = memory_max }
++                    '' else ""}
++                  print value
+               }' /proc/meminfo)
+ 
+               ${pkgs.utillinux}/sbin/zramctl --size $mem --algorithm ${cfg.algorithm} /dev/${dev}