[PATCH 4.14 239/496] selftests/vm/run_vmtests: adjust hugetlb size according to nr_cpus

From: Greg Kroah-Hartman
Date: Mon May 28 2018 - 09:07:36 EST


4.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Li Zhijian <zhijianx.li@xxxxxxxxx>

[ Upstream commit 0627be7d3c871035364923559543c9b2ff5357f2 ]

Fix userfaultfd_hugetlb on hosts which have more than 64 cpus.

---------------------------
running userfaultfd_hugetlb
---------------------------
invalid MiB
Usage: <MiB> <bounces>
[FAIL]

Via userfaultfd.c we can know, hugetlb_size needs to meet hugetlb_size
>= nr_cpus * hugepage_size. hugepage_size is often 2M, so when host
cpus > 64, it requires more than 128M.

[zhijianx.li@xxxxxxxxx: update changelog/comments and variable name]
Link: http://lkml.kernel.org/r/20180302024356.83359-1-zhijianx.li@xxxxxxxxx
Link: http://lkml.kernel.org/r/20180303125027.81638-1-zhijianx.li@xxxxxxxxx
Link: http://lkml.kernel.org/r/20180302024356.83359-1-zhijianx.li@xxxxxxxxx
Signed-off-by: Li Zhijian <zhijianx.li@xxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: SeongJae Park <sj38.park@xxxxxxxxx>
Cc: Philippe Ombredanne <pombredanne@xxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/vm/run_vmtests | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)

--- a/tools/testing/selftests/vm/run_vmtests
+++ b/tools/testing/selftests/vm/run_vmtests
@@ -2,25 +2,33 @@
# SPDX-License-Identifier: GPL-2.0
#please run as root

-#we need 256M, below is the size in kB
-needmem=262144
mnt=./huge
exitcode=0

-#get pagesize and freepages from /proc/meminfo
+#get huge pagesize and freepages from /proc/meminfo
while read name size unit; do
if [ "$name" = "HugePages_Free:" ]; then
freepgs=$size
fi
if [ "$name" = "Hugepagesize:" ]; then
- pgsize=$size
+ hpgsize_KB=$size
fi
done < /proc/meminfo

+# Simple hugetlbfs tests have a hardcoded minimum requirement of
+# huge pages totaling 256MB (262144KB) in size. The userfaultfd
+# hugetlb test requires a minimum of 2 * nr_cpus huge pages. Take
+# both of these requirements into account and attempt to increase
+# number of huge pages available.
+nr_cpus=$(nproc)
+hpgsize_MB=$((hpgsize_KB / 1024))
+half_ufd_size_MB=$((((nr_cpus * hpgsize_MB + 127) / 128) * 128))
+needmem_KB=$((half_ufd_size_MB * 2 * 1024))
+
#set proper nr_hugepages
-if [ -n "$freepgs" ] && [ -n "$pgsize" ]; then
+if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
nr_hugepgs=`cat /proc/sys/vm/nr_hugepages`
- needpgs=`expr $needmem / $pgsize`
+ needpgs=$((needmem_KB / hpgsize_KB))
tries=2
while [ $tries -gt 0 ] && [ $freepgs -lt $needpgs ]; do
lackpgs=$(( $needpgs - $freepgs ))
@@ -107,8 +115,9 @@ fi
echo "---------------------------"
echo "running userfaultfd_hugetlb"
echo "---------------------------"
-# 256MB total huge pages == 128MB src and 128MB dst
-./userfaultfd hugetlb 128 32 $mnt/ufd_test_file
+# Test requires source and destination huge pages. Size of source
+# (half_ufd_size_MB) is passed as argument to test.
+./userfaultfd hugetlb $half_ufd_size_MB 32 $mnt/ufd_test_file
if [ $? -ne 0 ]; then
echo "[FAIL]"
exitcode=1