The throttle test cases uses _throtl_issue_io function to submit IO to
the device. This function typically runs in the background process however
before this function starts execution and submit IO, we need to set the PID
of the background process into cgroup.procs. The current implementation
adds sleep 0.1 before _throtl_issue_io and it's assumed that during this
sleep time of 0.1 second we shall be able to write the PID of the background
process to cgroup.procs. However this may not be always true as background
process might starts running after sleep of 0.1 seconds (and hence start
submitting IO) before we could actually write the PID of background process
into cgroup.procs.
This commit helps fix the above race condition by touching a temp file. The
the existence of the temp file is then polled by the background process at
regular interval. Until the temp file is created, the background process
would not forward progress and starts submitting IO and from the main
thread we'd touch temp file only after we write PID of the background
process into cgroup.procs.
Signed-off-by: Nilay Shroff <nilay@xxxxxxxxxxxxx>
---
tests/throtl/004 | 8 +++++++-
tests/throtl/005 | 9 ++++++++-
tests/throtl/rc | 9 ++++++++-
3 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/tests/throtl/004 b/tests/throtl/004
index 6e28612..44b33ec 100755
--- a/tests/throtl/004
+++ b/tests/throtl/004
@@ -21,12 +21,18 @@ test() {
_throtl_set_limits wbps=$((1024 * 1024))
{
- sleep 0.1
+ while true; do
+ if [[ -e "$TMPDIR/test-io" ]]; then
+ break
+ fi
+ sleep 0.1
+ done
_throtl_issue_io write 10M 1
} &
local pid=$!
echo "$pid" > "$CGROUP2_DIR/$THROTL_DIR/cgroup.procs"
+ touch "$TMPDIR/test-io"
sleep 0.6
echo 0 > "/sys/kernel/config/nullb/$THROTL_DEV/power"
diff --git a/tests/throtl/005 b/tests/throtl/005
index 0778258..4797ea3 100755
--- a/tests/throtl/005
+++ b/tests/throtl/005
@@ -20,12 +20,19 @@ test() {
_throtl_set_limits wbps=$((512 * 1024))
{
- sleep 0.1
+ while true; do
+ if [[ -e "$TMPDIR/test-io" ]]; then
+ break
+ fi
+ sleep 0.1
+ done
+
_throtl_issue_io write 1M 1
} &
local pid=$!
echo "$pid" > "$CGROUP2_DIR/$THROTL_DIR/cgroup.procs"
+ touch "$TMPDIR/test-io"
sleep 1
_throtl_set_limits wbps=$((256 * 1024))
diff --git a/tests/throtl/rc b/tests/throtl/rc
index 330e6b9..a9c1889 100644
--- a/tests/throtl/rc
+++ b/tests/throtl/rc
@@ -104,11 +104,18 @@ _throtl_test_io() {
local bs=$2
local count=$3
- sleep 0.1
+ while true; do
+ if [[ -e "$TMPDIR/test-io" ]]; then
+ break
+ fi
+ sleep 0.1
+ done
_throtl_issue_io "$rw" "$bs" "$count"
} &
pid=$!
echo "$pid" > "$CGROUP2_DIR/$THROTL_DIR/cgroup.procs"
+ touch "$TMPDIR/test-io"
wait $pid
+ rm "$TMPDIR/test-io"
}
--
2.45.2
