From 86ef67db1a04d2002e691c350fbc937fb36df95d Mon Sep 17 00:00:00 2001 From: Janusz Krzysztofik Date: Thu, 23 Oct 2025 10:25:20 +0200 Subject: [PATCH] drm/i915: Wait longer for threads in migrate selftest on CHV/BXT+VTD When running on a Cherryview, or on a Broxton with VTD enabled, pinning of a VMA to GGTT is now committed asynchronously to avoid lock inversion among reservation_ww and cpu_hotplug locks, the latter acquired from stop_machine(). That may defer further processing of resources that depend on that VMA. As a consequence, a 10ms delay in a multithreaded migrate test case may occur too short and still incomplete threads may be interrupted, and the test case may fail with -ERESTARTSYS or -EINTR error code returned by any of those threads. Extend the delay to empirically determined 100ms on affected platforms. v3: Add an in-line comment that explains why 100ms (Andi). v2: Fix spelling (Sebastian, Krzysztof), - explain why VMA pinning is commited asynchronously on CHV/BXT+VTD (Krzysztof). Cc: Andi Shyti Signed-off-by: Janusz Krzysztofik Reviewed-by: Sebastian Brzezinka Reviewed-by: Krzysztof Karas Acked-by: Andi Shyti Signed-off-by: Andi Shyti Link: https://lore.kernel.org/r/20251023082925.351307-7-janusz.krzysztofik@linux.intel.com --- drivers/gpu/drm/i915/gt/selftest_migrate.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gt/selftest_migrate.c b/drivers/gpu/drm/i915/gt/selftest_migrate.c index 54bc447efce0b..fdf0e98586076 100644 --- a/drivers/gpu/drm/i915/gt/selftest_migrate.c +++ b/drivers/gpu/drm/i915/gt/selftest_migrate.c @@ -710,7 +710,14 @@ static int threaded_migrate(struct intel_migrate *migrate, thread[i].tsk = tsk; } - msleep(10 * n_cpus); /* start all threads before we kthread_stop() */ + /* + * Start all threads before we kthread_stop(). + * In CHV / BXT+VTD environments, where VMA pinning is committed + * asynchronously, empirically determined 100ms delay is needed + * to avoid stopping threads that may still wait for completion of + * intel_ggtt_bind_vma and fail with -ERESTARTSYS when interrupted. + */ + msleep((intel_vm_no_concurrent_access_wa(migrate->context->vm->i915) ? 100 : 10) * n_cpus); for (i = 0; i < n_cpus; ++i) { struct task_struct *tsk = thread[i].tsk; -- 2.47.3