From f44829e9fcd7b2d960677bdbb9e5d7a3bc2078a0 Mon Sep 17 00:00:00 2001
From: Michel Alexandre Salim <salimma@fedoraproject.org>
Date: Wed, 21 Jul 2021 15:18:49 -0700
Subject: [PATCH] Add macros.build-constraints

Signed-off-by: Michel Alexandre Salim <salimma@fedoraproject.org>
---
 epel-rpm-macros.spec     | 13 ++++++++++++-
 macros.build-constraints | 10 ++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 macros.build-constraints

diff --git a/epel-rpm-macros.spec b/epel-rpm-macros.spec
index 41b73bb..007962b 100644
--- a/epel-rpm-macros.spec
+++ b/epel-rpm-macros.spec
@@ -1,6 +1,6 @@
 Name:           epel-rpm-macros
 Version:        8
-Release:        22
+Release:        23
 Summary:        Extra Packages for Enterprise Linux RPM macros
 
 Group:          System Environment/Base
@@ -15,6 +15,8 @@ Source1:        macros.zzz-epel-override
 Source2:        gpgverify
 Source3:        pythondist.attr
 Source9:        GPL
+# misc macros
+Source150:      macros.build-constraints
 
 BuildArch:      noarch
 Requires:       redhat-release >= %{version}
@@ -55,6 +57,10 @@ install -Dpm 755 %{SOURCE2} \
 install -Dpm 644 %{SOURCE3} \
     %{buildroot}%{_fileattrsdir}/pythondist.attr
 
+# misc macros
+install -Dpm 644 %{SOURCE150} \
+    %{buildroot}/usr/lib/rpm/macros.d/macros.build-constraints
+
 
 %files
 %license GPL
@@ -62,9 +68,14 @@ install -Dpm 644 %{SOURCE3} \
 /etc/rpm/macros.zzz-epel-override
 %{_rpmconfigdir}/gpgverify
 %{_fileattrsdir}/pythondist.attr
+# misc macros
+/usr/lib/rpm/macros.d/macros.build-constraints
 
 
 %changelog
+* Sat Jul 24 2021 Michel Alexandre Salim <salimma@fedoraproject.org> - 8-23
+- Add macros.build-constraints
+
 * Wed Jul 14 2021 Miro Hrončok <mhroncok@redhat.com> - 8-22
 - Introduce %%py3_check_import
 
diff --git a/macros.build-constraints b/macros.build-constraints
new file mode 100644
index 0000000..1343cd8
--- /dev/null
+++ b/macros.build-constraints
@@ -0,0 +1,10 @@
+# Macros to constrain resource use during the build process
+
+# m: memory limit in MBs per core; default is 1024
+%limit_build(m:) \
+  _mem_per_process="%{-m:%{-m*}}%{!-m:1024}" \
+  _max_mem=$(awk '/MemTotal/ { print $2 }' /proc/meminfo) \
+  _max_jobs="$(($_max_mem / ($_mem_per_process * 1024)))" \
+  _cur_max_jobs="%{_smp_build_ncpus}" \
+  test "${_cur_max_jobs}" -gt "${_max_jobs}" && _cur_max_jobs="${_max_jobs}" && echo "Warning: Reducing build parallelism to -j${_max_jobs} because of memory limits" \
+  %global _smp_build_ncpus "${_cur_max_jobs}"