From: Chris Wilson Date: Tue, 3 Mar 2020 14:00:09 +0000 (+0000) Subject: drm/i915/gt: Drop the timeline->mutex as we wait for retirement X-Git-Tag: v5.7-rc1~136^2~11^2~105 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=82126e596d8519baac416aee83cad938f1d23cf8;p=thirdparty%2Fkernel%2Flinux.git drm/i915/gt: Drop the timeline->mutex as we wait for retirement 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") Fixes: f33a8a51602c ("drm/i915: Merge wait_for_timelines with retire_request") Signed-off-by: Chris Wilson Cc: Mika Kuoppala Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20200303140009.1494819-1-chris@chris-wilson.co.uk --- diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c index 8a5054f21bf88..24c99d0838af6 100644 --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c @@ -147,24 +147,32 @@ 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); + + /* Retirement is best effort */ + if (!mutex_trylock(&tl->mutex)) { + 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 */ + /* Resume list iteration after reacquiring spinlock */ list_safe_reset_next(tl, tn, link); if (atomic_dec_and_test(&tl->active_count)) list_del(&tl->link); - mutex_unlock(&tl->mutex); /* Defer the final release to after the spinlock */ if (refcount_dec_and_test(&tl->kref.refcount)) {