From e32f2cda301289b92c4fe3f25a8b38267f03d4ff Mon Sep 17 00:00:00 2001
From: Default email <noreply+nixpkgs@lukegb.com>
Date: Tue, 24 Nov 2020 21:58:05 +0100
Subject: [PATCH] Project import generated by Copybara.

GitOrigin-RevId: 6f0c00907bbd81b47052eef59f7b284926a77289
---
 .../nixpkgs/nixos/modules/config/zram.nix        | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/third_party/nixpkgs/nixos/modules/config/zram.nix b/third_party/nixpkgs/nixos/modules/config/zram.nix
index 341101bc18..1f513b7e4d 100644
--- a/third_party/nixpkgs/nixos/modules/config/zram.nix
+++ b/third_party/nixpkgs/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);
+                    ${lib.optionalString (cfg.memoryMax != null) ''
+                      memory_max=int(${toString cfg.memoryMax}/${toString devicesCount});
+                      if (value > memory_max) { value = memory_max }
+                    ''}
+                  print value
               }' /proc/meminfo)
 
               ${pkgs.util-linux}/sbin/zramctl --size $mem --algorithm ${cfg.algorithm} /dev/${dev}