selftests: vm: Try harder to allocate huge pages

debian/patches/bugfix/all/selftests-vm-try-harder-to-allocate-huge-pages.patch

@@ -0,0 +1,40 @@
+From: Ben Hutchings <ben@decadent.org.uk>
+Date: Sat, 31 Oct 2015 17:56:11 +0000
+Subject: selftests: vm: Try harder to allocate huge pages
+
+If we need to increase the number of huge pages, drop caches first
+to reduce fragmentation and then check that we actually allocated
+as many as we wanted.  Retry once if that doesn't work.
+
+Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
+---
+--- a/tools/testing/selftests/vm/run_vmtests
++++ b/tools/testing/selftests/vm/run_vmtests
+@@ -20,13 +20,26 @@ done < /proc/meminfo
+ if [ -n "$freepgs" ] && [ -n "$pgsize" ]; then
+ 	nr_hugepgs=`cat /proc/sys/vm/nr_hugepages`
+ 	needpgs=`expr $needmem / $pgsize`
+-	if [ $freepgs -lt $needpgs ]; then
++	tries=2
++	while [ $tries -gt 0 ] && [ $freepgs -lt $needpgs ]; do
+ 		lackpgs=$(( $needpgs - $freepgs ))
++		echo 3 > /proc/sys/vm/drop_caches
+ 		echo $(( $lackpgs + $nr_hugepgs )) > /proc/sys/vm/nr_hugepages
+ 		if [ $? -ne 0 ]; then
+ 			echo "Please run this test as root"
+ 			exit 1
+ 		fi
++		while read name size unit; do
++			if [ "$name" = "HugePages_Free:" ]; then
++				freepgs=$size
++			fi
++		done < /proc/meminfo
++		tries=$((tries - 1))
++	done
++	if [ $freepgs -lt $needpgs ]; then
++		printf "Not enough huge pages available (%d < %d)\n" \
++		       $freepgs $needpgs
++		exit 1
+ 	fi
+ else
+ 	echo "no hugetlbfs support in kernel?"

debian/patches/series

@@ -86,3 +86,4 @@ bugfix/all/selftests-add-missing-include-directives.patch
 bugfix/all/selftests-memfd-stop-unnecessary-rebuilds.patch
 bugfix/all/selftests-kprobe-choose-an-always-defined-function-t.patch
 bugfix/all/selftests-make-scripts-executable.patch
+bugfix/all/selftests-vm-try-harder-to-allocate-huge-pages.patch