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.

Changes since v1: - update changelog/comments and variable name to make code more easier to read/understand(stolen from Mike Kravetz)

Link: http://lkml.kernel.org/r/20180302024356.83359-1-zhijianx.li@intel.com Signed-off-by: Li Zhijian zhijianx.li@intel.com Cc: Shuah Khan shuah@kernel.org Cc: SeongJae Park sj38.park@gmail.com Cc: Philippe Ombredanne pombredanne@nexb.com Cc: Aneesh Kumar K.V aneesh.kumar@linux.vnet.ibm.com Cc: Mike Kravetz mike.kravetz@oracle.com Signed-off-by: Andrew Morton akpm@linux-foundation.org --- tools/testing/selftests/vm/run_vmtests | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/vm/run_vmtests b/tools/testing/selftests/vm/run_vmtests index d2561895a021a..22d5646738302 100755 --- 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