diff --git a/_constraints b/_constraints
index 6200bf7..c533cff 100644
--- a/_constraints
+++ b/_constraints
@@ -7,8 +7,10 @@
     <memory>
       <size unit="G">5</size>
     </memory>
+    <!--
     <memoryperjob>
-      <size unit="M">2200</size>
+      <size unit="M">2500</size>
     </memoryperjob>
+    -->
   </hardware>
 </constraints>
diff --git a/openscad.changes b/openscad.changes
index 29ef7b4..6948b24 100644
--- a/openscad.changes
+++ b/openscad.changes
@@ -1,3 +1,15 @@
+-------------------------------------------------------------------
+Sat May  8 07:00:15 UTC 2021 - Samu Voutilainen <smar@smar.fi>
+
+- Reintroduce memory-contraints macro %limit_build -m 2500.
+  Constraint memoryperjob is allowing too small workers for 
+  the jobs it provides.
+
+-------------------------------------------------------------------
+Thu May  6 05:08:29 UTC 2021 - Samu Voutilainen <smar@smar.fi>
+
+- Increased memoryperjob constraint to 2500 MB.
+
 -------------------------------------------------------------------
 Tue Apr 20 11:48:29 UTC 2021 - Samu Voutilainen <smar@smar.fi>
 
diff --git a/openscad.spec b/openscad.spec
index 876979c..09b3d92 100644
--- a/openscad.spec
+++ b/openscad.spec
@@ -39,6 +39,7 @@ BuildRequires:  libboost_thread-devel
 BuildRequires:  libcgal-devel
 BuildRequires:  libqscintilla-qt5-devel
 BuildRequires:  libspnav-devel
+BuildRequires:  memory-constraints
 BuildRequires:  opencsg-devel
 BuildRequires:  pkgconfig
 BuildRequires:  pkgconfig(Qt5Concurrent)
@@ -64,6 +65,9 @@ aspects, e.g. modelling of machine parts.
 
 %build
 %qmake5 PREFIX=%{_prefix} CONFIG+=qopenglwidget CONFIG+=c++14
+# As of 08.05.2021, memoryperjob constraint is not working correctly,
+# so limit memory per job here.
+%limit_build -m 2500
 %make_build
 
 %install