Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Waiman Long <longman@redhat.com>,
        Mina Almasry <almasrymina@google.com>,
        Shuah Khan <shuah@kernel.org>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0831/1039] selftests/vm: make charge_reserved_hugetlb.sh work with existing cgroup setting
Date:   Mon, 24 Jan 2022 19:43:40 +0100
Message-Id: <20220124184153.217227973@linuxfoundation.org>
In-Reply-To: <20220124184125.121143506@linuxfoundation.org>
References: <20220124184125.121143506@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Waiman Long <longman@redhat.com>

[ Upstream commit 209376ed2a8431ccb4c40fdcef11194fc1e749b0 ]

The hugetlb cgroup reservation test charge_reserved_hugetlb.sh assume
that no cgroup filesystems are mounted before running the test.  That is
not true in many cases.  As a result, the test fails to run.  Fix that
by querying the current cgroup mount setting and using the existing
cgroup setup instead before attempting to freshly mount a cgroup
filesystem.

Similar change is also made for hugetlb_reparenting_test.sh as well,
though it still has problem if cgroup v2 isn't used.

The patched test scripts were run on a centos 8 based system to verify
that they ran properly.

Link: https://lkml.kernel.org/r/20220106201359.1646575-1-longman@redhat.com
Fixes: 29750f71a9b4 ("hugetlb_cgroup: add hugetlb_cgroup reservation tests")
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Mina Almasry <almasrymina@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../selftests/vm/charge_reserved_hugetlb.sh   | 34 +++++++++++--------
 .../selftests/vm/hugetlb_reparenting_test.sh  | 21 +++++++-----
 .../selftests/vm/write_hugetlb_memory.sh      |  2 +-
 3 files changed, 34 insertions(+), 23 deletions(-)

diff --git a/tools/testing/selftests/vm/charge_reserved_hugetlb.sh b/tools/testing/selftests/vm/charge_reserved_hugetlb.sh
index fe8fcfb334e06..a5cb4b09a46c4 100644
--- a/tools/testing/selftests/vm/charge_reserved_hugetlb.sh
+++ b/tools/testing/selftests/vm/charge_reserved_hugetlb.sh
@@ -24,19 +24,23 @@ if [[ "$1" == "-cgroup-v2" ]]; then
   reservation_usage_file=rsvd.current
 fi
 
-cgroup_path=/dev/cgroup/memory
-if [[ ! -e $cgroup_path ]]; then
-  mkdir -p $cgroup_path
-  if [[ $cgroup2 ]]; then
+if [[ $cgroup2 ]]; then
+  cgroup_path=$(mount -t cgroup2 | head -1 | awk -e '{print $3}')
+  if [[ -z "$cgroup_path" ]]; then
+    cgroup_path=/dev/cgroup/memory
     mount -t cgroup2 none $cgroup_path
-  else
+    do_umount=1
+  fi
+  echo "+hugetlb" >$cgroup_path/cgroup.subtree_control
+else
+  cgroup_path=$(mount -t cgroup | grep ",hugetlb" | awk -e '{print $3}')
+  if [[ -z "$cgroup_path" ]]; then
+    cgroup_path=/dev/cgroup/memory
     mount -t cgroup memory,hugetlb $cgroup_path
+    do_umount=1
   fi
 fi
-
-if [[ $cgroup2 ]]; then
-  echo "+hugetlb" >/dev/cgroup/memory/cgroup.subtree_control
-fi
+export cgroup_path
 
 function cleanup() {
   if [[ $cgroup2 ]]; then
@@ -108,7 +112,7 @@ function setup_cgroup() {
 
 function wait_for_hugetlb_memory_to_get_depleted() {
   local cgroup="$1"
-  local path="/dev/cgroup/memory/$cgroup/hugetlb.${MB}MB.$reservation_usage_file"
+  local path="$cgroup_path/$cgroup/hugetlb.${MB}MB.$reservation_usage_file"
   # Wait for hugetlbfs memory to get depleted.
   while [ $(cat $path) != 0 ]; do
     echo Waiting for hugetlb memory to get depleted.
@@ -121,7 +125,7 @@ function wait_for_hugetlb_memory_to_get_reserved() {
   local cgroup="$1"
   local size="$2"
 
-  local path="/dev/cgroup/memory/$cgroup/hugetlb.${MB}MB.$reservation_usage_file"
+  local path="$cgroup_path/$cgroup/hugetlb.${MB}MB.$reservation_usage_file"
   # Wait for hugetlbfs memory to get written.
   while [ $(cat $path) != $size ]; do
     echo Waiting for hugetlb memory reservation to reach size $size.
@@ -134,7 +138,7 @@ function wait_for_hugetlb_memory_to_get_written() {
   local cgroup="$1"
   local size="$2"
 
-  local path="/dev/cgroup/memory/$cgroup/hugetlb.${MB}MB.$fault_usage_file"
+  local path="$cgroup_path/$cgroup/hugetlb.${MB}MB.$fault_usage_file"
   # Wait for hugetlbfs memory to get written.
   while [ $(cat $path) != $size ]; do
     echo Waiting for hugetlb memory to reach size $size.
@@ -574,5 +578,7 @@ for populate in "" "-o"; do
   done     # populate
 done       # method
 
-umount $cgroup_path
-rmdir $cgroup_path
+if [[ $do_umount ]]; then
+  umount $cgroup_path
+  rmdir $cgroup_path
+fi
diff --git a/tools/testing/selftests/vm/hugetlb_reparenting_test.sh b/tools/testing/selftests/vm/hugetlb_reparenting_test.sh
index 4a9a3afe9fd4d..bf2d2a684edfd 100644
--- a/tools/testing/selftests/vm/hugetlb_reparenting_test.sh
+++ b/tools/testing/selftests/vm/hugetlb_reparenting_test.sh
@@ -18,19 +18,24 @@ if [[ "$1" == "-cgroup-v2" ]]; then
   usage_file=current
 fi
 
-CGROUP_ROOT='/dev/cgroup/memory'
-MNT='/mnt/huge/'
 
-if [[ ! -e $CGROUP_ROOT ]]; then
-  mkdir -p $CGROUP_ROOT
-  if [[ $cgroup2 ]]; then
+if [[ $cgroup2 ]]; then
+  CGROUP_ROOT=$(mount -t cgroup2 | head -1 | awk -e '{print $3}')
+  if [[ -z "$CGROUP_ROOT" ]]; then
+    CGROUP_ROOT=/dev/cgroup/memory
     mount -t cgroup2 none $CGROUP_ROOT
-    sleep 1
-    echo "+hugetlb +memory" >$CGROUP_ROOT/cgroup.subtree_control
-  else
+    do_umount=1
+  fi
+  echo "+hugetlb +memory" >$CGROUP_ROOT/cgroup.subtree_control
+else
+  CGROUP_ROOT=$(mount -t cgroup | grep ",hugetlb" | awk -e '{print $3}')
+  if [[ -z "$CGROUP_ROOT" ]]; then
+    CGROUP_ROOT=/dev/cgroup/memory
     mount -t cgroup memory,hugetlb $CGROUP_ROOT
+    do_umount=1
   fi
 fi
+MNT='/mnt/huge/'
 
 function get_machine_hugepage_size() {
   hpz=$(grep -i hugepagesize /proc/meminfo)
diff --git a/tools/testing/selftests/vm/write_hugetlb_memory.sh b/tools/testing/selftests/vm/write_hugetlb_memory.sh
index d3d0d108924d4..70a02301f4c27 100644
--- a/tools/testing/selftests/vm/write_hugetlb_memory.sh
+++ b/tools/testing/selftests/vm/write_hugetlb_memory.sh
@@ -14,7 +14,7 @@ want_sleep=$8
 reserve=$9
 
 echo "Putting task in cgroup '$cgroup'"
-echo $$ > /dev/cgroup/memory/"$cgroup"/cgroup.procs
+echo $$ > ${cgroup_path:-/dev/cgroup/memory}/"$cgroup"/cgroup.procs
 
 echo "Method is $method"
 
-- 
2.34.1