Commit e5661c6a authored by Chris Wilson's avatar Chris Wilson
Browse files

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

drivers/gpu/drm/i915/gem/selftests/i915_gem_context.c

+2 −0
Original line number Diff line number Diff line
@@ -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;

drivers/gpu/drm/i915/gem/selftests/i915_gem_object_blt.c

+2 −0
Original line number Diff line number Diff line
@@ -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;

drivers/gpu/drm/i915/gt/selftest_hangcheck.c

+2 −0
Original line number Diff line number Diff line
@@ -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 {

drivers/gpu/drm/i915/gt/selftest_lrc.c

+2 −0
Original line number Diff line number Diff line
@@ -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;

drivers/gpu/drm/i915/selftests/i915_request.c

+4 −0
Original line number Diff line number Diff line
@@ -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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