Commit e5661c6a authored by Chris Wilson's avatar Chris Wilson

drm/i915/selftests: Start kthreads before stopping

An interesting observation made with our parallel selftests was that on
our small/single cpu systems we would call kthread_stop() before the
kthreads were spawned. If this happens, the kthread is never run at all;
completely bypassing the test.

A simple yield() from the parent will ensure that all children have the
opportunity to start before we reap them.
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191101084940.31838-1-chris@chris-wilson.co.uk
parent 292a27b0
......@@ -345,6 +345,8 @@ static int live_parallel_switch(void *arg)
get_task_struct(data[n].tsk);
}
yield(); /* start all threads before we kthread_stop() */
for (n = 0; n < count; n++) {
int status;
......
......@@ -473,6 +473,8 @@ static int igt_threaded_blt(struct drm_i915_private *i915,
get_task_struct(tsk[i]);
}
yield(); /* start all threads before we kthread_stop() */
for (i = 0; i < n_cpus; ++i) {
int status;
......
......@@ -826,6 +826,8 @@ static int __igt_reset_engines(struct intel_gt *gt,
get_task_struct(tsk);
}
yield(); /* start all threads before we begin */
intel_engine_pm_get(engine);
set_bit(I915_RESET_ENGINE + id, &gt->reset.flags);
do {
......
......@@ -2252,6 +2252,8 @@ static int smoke_crescendo(struct preempt_smoke *smoke, unsigned int flags)
get_task_struct(tsk[id]);
}
yield(); /* start all threads before we kthread_stop() */
count = 0;
for_each_engine(engine, smoke->gt, id) {
int status;
......
......@@ -464,6 +464,7 @@ static int mock_breadcrumbs_smoketest(void *arg)
get_task_struct(threads[n]);
}
yield(); /* start all threads before we begin */
msleep(jiffies_to_msecs(i915_selftest.timeout_jiffies));
for (n = 0; n < ncpus; n++) {
......@@ -1158,6 +1159,8 @@ static int live_parallel_engines(void *arg)
get_task_struct(tsk[idx++]);
}
yield(); /* start all threads before we kthread_stop() */
idx = 0;
for_each_uabi_engine(engine, i915) {
int status;
......@@ -1314,6 +1317,7 @@ static int live_breadcrumbs_smoketest(void *arg)
idx++;
}
yield(); /* start all threads before we begin */
msleep(jiffies_to_msecs(i915_selftest.timeout_jiffies));
out_flush:
......
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