Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: > As we have pinned the timeline (using tl->active_count), we can safely > drop the tl->mutex as we wait for what we believe to be the final > request on that timeline. This is useful for ensuring that we do not > block the engine heartbeat by hogging the kernel_context's timeline on a > dead GPU. > > References: https://gitlab.freedesktop.org/drm/intel/issues/1364 > Fixes: 058179e72e09 ("drm/i915/gt: Replace hangcheck by heartbeats") > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/gt/intel_gt_requests.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c > index 8a5054f21bf8..436412d07689 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c > +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c > @@ -147,24 +147,31 @@ long intel_gt_retire_requests_timeout(struct intel_gt *gt, long timeout) > > fence = i915_active_fence_get(&tl->last_request); > if (fence) { > + mutex_unlock(&tl->mutex); > + > timeout = dma_fence_wait_timeout(fence, > interruptible, > timeout); > dma_fence_put(fence); > + > + if (!mutex_trylock(&tl->mutex)) { If you can't take it, it must be active and for the retirement advancement we can bail out early. Or is there something else with a sampled try? > + active_count++; > + goto out_active; > + } > } > } > > if (!retire_requests(tl) || flush_submission(gt)) > active_count++; > + mutex_unlock(&tl->mutex); > > - spin_lock(&timelines->lock); > +out_active: spin_lock(&timelines->lock); > > /* Resume iteration after dropping lock */ You either fixed this comment with this patch. Or that the comment remains a highly confusing. > list_safe_reset_next(tl, tn, link); > if (atomic_dec_and_test(&tl->active_count)) > list_del(&tl->link); We have the timelines lock and the above seems safe wtithout the actual mutex. But the comment is still hauting me. -Mika > > - mutex_unlock(&tl->mutex); > > /* Defer the final release to after the spinlock */ > if (refcount_dec_and_test(&tl->kref.refcount)) { > -- > 2.25.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
