From 0cf627b4e305f5cbaf53e3f10209092b7bd77c1b Mon Sep 17 00:00:00 2001
From: Nathan Cutler <ncutler@suse.com>
Date: Thu, 19 May 2016 20:03:29 +0200
Subject: [PATCH] build/ops: rpm: override %_smp_mflags if not enough memory
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Sometimes the build machine has lots of processor cores and not enough
memory to successfully build Ceph on all of them at once. Calculate
how many parallel build processes we can sustain with the memory we
have and set a lower build parallelism if necessary. Never exceed
the value set by %_smp_mflags even if memory is aplenty.

Credits to Tomáš Chvátal for the original idea and implementation.

Signed-off-by: Nathan Cutler <ncutler@suse.com>
---
 ceph.spec.in | 44 +++++++++++++++++++++++++++-----------------
 1 file changed, 27 insertions(+), 17 deletions(-)

diff --git a/ceph.spec.in b/ceph.spec.in
index 679e2fc6b15..8ea8e09d8c6 100644
--- a/ceph.spec.in
+++ b/ceph.spec.in
@@ -21,12 +21,10 @@
 %else
 %bcond_without tcmalloc
 %endif
-%bcond_with lowmem_builder
 %if 0%{?fedora} || 0%{?rhel}
 %bcond_without selinux
 %bcond_without ceph_test_package
 %bcond_without cephfs_java
-%bcond_with lowmem_builder
 %bcond_without lttng
 %global _remote_tarball_prefix https://download.ceph.com/tarballs/
 %endif
@@ -34,7 +32,6 @@
 %bcond_with selinux
 %bcond_with ceph_test_package
 %bcond_with cephfs_java
-%bcond_without lowmem_builder
 #Compat macro for new _fillupdir macro introduced in Nov 2017
 %if ! %{defined _fillupdir}
 %global _fillupdir /var/adm/fillup-templates
@@ -152,6 +149,7 @@ BuildRequires:	make
 BuildRequires:	parted
 BuildRequires:	perl
 BuildRequires:	pkgconfig
+BuildRequires:  procps
 BuildRequires:	python
 BuildRequires:	python-devel
 BuildRequires:	python-nose
@@ -813,7 +811,8 @@ for i in /usr/{lib64,lib}/jvm/java/include{,/linux}; do
 done
 %endif
 
-%if %{with lowmem_builder}
+%if 0%{?suse_version}
+# the following setting fixed an OOM condition we once encountered in the OBS
 RPM_OPT_FLAGS="$RPM_OPT_FLAGS --param ggc-min-expand=20 --param ggc-min-heapsize=32768"
 %endif
 export RPM_OPT_FLAGS=`echo $RPM_OPT_FLAGS | sed -e 's/i386/i486/'`
@@ -822,18 +821,29 @@ export CPPFLAGS="$java_inc"
 export CFLAGS="$RPM_OPT_FLAGS"
 export CXXFLAGS="$RPM_OPT_FLAGS"
 
-env | sort
-
-%if %{with lowmem_builder}
-%if 0%{?jobs} > 8
-%define _smp_mflags -j8
-%endif
-%endif
+# Parallel build settings ...
+CEPH_MFLAGS_JOBS="%{?_smp_mflags}"
+CEPH_SMP_NCPUS=$(echo "$CEPH_MFLAGS_JOBS" | sed 's/-j//')
+%if 0%{?__isa_bits} == 32
+# 32-bit builds can use 3G memory max, which is not enough even for -j2
+CEPH_SMP_NCPUS="1"
+%endif
+# do not eat all memory
+echo "Available memory:"
+free -h
+echo "System limits:"
+ulimit -a
+if test -n "$CEPH_SMP_NCPUS" -a "$CEPH_SMP_NCPUS" -gt 1 ; then
+    mem_per_process=1800
+    max_mem=$(LANG=C free -m | sed -n "s|^Mem: *\([0-9]*\).*$|\1|p")
+    max_jobs="$(($max_mem / $mem_per_process))"
+    test "$CEPH_SMP_NCPUS" -gt "$max_jobs" && CEPH_SMP_NCPUS="$max_jobs" && echo "Warning: Reducing build parallelism to -j$max_jobs because of memory limits"
+    test "$CEPH_SMP_NCPUS" -le 0 && CEPH_SMP_NCPUS="1" && echo "Warning: Not using parallel build at all because of memory limits"
+fi
+export CEPH_SMP_NCPUS
+export CEPH_MFLAGS_JOBS="-j$CEPH_SMP_NCPUS"
 
-# unlimit _smp_mflags in system macro if not set above
-%define _smp_ncpus_max 0
-# extract the number of processors for use with cmake
-%define _smp_ncpus %(echo %{_smp_mflags} | sed 's/-j//')
+env | sort
 
 mkdir build
 cd build
@@ -878,9 +888,9 @@ cmake .. \
 %else
     -DWITH_BOOST_CONTEXT=OFF \
 %endif
-    -DBOOST_J=%{_smp_ncpus}
+    -DBOOST_J=$CEPH_SMP_NCPUS
 
-make %{?_smp_mflags}
+make "$CEPH_MFLAGS_JOBS"
 
 
 %if 0%{with make_check}
-- 
2.39.5