On Wed, Jan 29, 2020 at 07:54:52PM +0000, Chris Wilson wrote: > On Braswell and Broxton (also known as Valleyview and Apollolake), we > need to serialise updates of the GGTT using the big stop_machine() > hammer. This has the side effect of appearing to lockdep as a possible > reclaim (since it uses the cpuhp mutex and that is tainted by per-cpu > allocations). However, we want to use vm->mutex (including ggtt->mutex) > from wthin the shrinker and so must avoid such possible taints. For this > purpose, we introduced the asynchronous vma binding and we can apply it > to the PIN_GLOBAL so long as take care to add the necessary waits for > the worker afterwards. > > Closes: https://gitlab.freedesktop.org/drm/intel/issues/211 > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Hm, isn't that just the usual "lockdep cant see past a wait on another thread" trick that doesn't actually fix anything? The locking context for the pte writes and the wait seem exactly the same, at first glance at least. I dont' really have a different idea though :-/ -Daniel > --- > drivers/gpu/drm/i915/gt/intel_engine_cs.c | 7 +++--- > drivers/gpu/drm/i915/gt/intel_ggtt.c | 1 + > drivers/gpu/drm/i915/gt/intel_gt.c | 2 +- > drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +- > drivers/gpu/drm/i915/gt/intel_ring.c | 6 ++--- > drivers/gpu/drm/i915/gt/intel_timeline.c | 4 ++-- > drivers/gpu/drm/i915/gt/uc/intel_guc.c | 4 ++-- > drivers/gpu/drm/i915/i915_gem.c | 6 +++++ > drivers/gpu/drm/i915/i915_vma.c | 27 ++++++++++++++++++++++- > drivers/gpu/drm/i915/i915_vma.h | 2 ++ > 10 files changed, 46 insertions(+), 15 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c > index 39fe9a5b4820..2504f4d05edf 100644 > --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c > +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c > @@ -527,7 +527,6 @@ static int pin_ggtt_status_page(struct intel_engine_cs *engine, > { > unsigned int flags; > > - flags = PIN_GLOBAL; > if (!HAS_LLC(engine->i915) && i915_ggtt_has_aperture(engine->gt->ggtt)) > /* > * On g33, we cannot place HWS above 256MiB, so > @@ -540,11 +539,11 @@ static int pin_ggtt_status_page(struct intel_engine_cs *engine, > * above the mappable region (even though we never > * actually map it). > */ > - flags |= PIN_MAPPABLE; > + flags = PIN_MAPPABLE; > else > - flags |= PIN_HIGH; > + flags = PIN_HIGH; > > - return i915_vma_pin(vma, 0, 0, flags); > + return i915_ggtt_pin(vma, 0, flags); > } > > static int init_status_page(struct intel_engine_cs *engine) > diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c > index 79096722ce16..6af50d62d712 100644 > --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c > +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c > @@ -881,6 +881,7 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt) > ggtt->vm.insert_page = bxt_vtd_ggtt_insert_page__BKL; > if (ggtt->vm.clear_range != nop_clear_range) > ggtt->vm.clear_range = bxt_vtd_ggtt_clear_range__BKL; > + ggtt->vm.bind_async_flags = I915_VMA_GLOBAL_BIND; > } > > ggtt->invalidate = gen8_ggtt_invalidate; > diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c > index 143268083135..bf6c0f949e35 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gt.c > +++ b/drivers/gpu/drm/i915/gt/intel_gt.c > @@ -345,7 +345,7 @@ static int intel_gt_init_scratch(struct intel_gt *gt, unsigned int size) > goto err_unref; > } > > - ret = i915_vma_pin(vma, 0, 0, PIN_GLOBAL | PIN_HIGH); > + ret = i915_ggtt_pin(vma, 0, PIN_HIGH); > if (ret) > goto err_unref; > > diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c > index 8f15ab7d8d88..e63ae4a17110 100644 > --- a/drivers/gpu/drm/i915/gt/intel_lrc.c > +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c > @@ -3259,7 +3259,7 @@ static int lrc_setup_wa_ctx(struct intel_engine_cs *engine) > goto err; > } > > - err = i915_vma_pin(vma, 0, 0, PIN_GLOBAL | PIN_HIGH); > + err = i915_ggtt_pin(vma, 0, PIN_HIGH); > if (err) > goto err; > > diff --git a/drivers/gpu/drm/i915/gt/intel_ring.c b/drivers/gpu/drm/i915/gt/intel_ring.c > index 374b28f13ca0..366013367526 100644 > --- a/drivers/gpu/drm/i915/gt/intel_ring.c > +++ b/drivers/gpu/drm/i915/gt/intel_ring.c > @@ -31,17 +31,15 @@ int intel_ring_pin(struct intel_ring *ring) > if (atomic_fetch_inc(&ring->pin_count)) > return 0; > > - flags = PIN_GLOBAL; > - > /* Ring wraparound at offset 0 sometimes hangs. No idea why. */ > - flags |= PIN_OFFSET_BIAS | i915_ggtt_pin_bias(vma); > + flags = PIN_OFFSET_BIAS | i915_ggtt_pin_bias(vma); > > if (vma->obj->stolen) > flags |= PIN_MAPPABLE; > else > flags |= PIN_HIGH; > > - ret = i915_vma_pin(vma, 0, 0, flags); > + ret = i915_ggtt_pin(vma, 0, flags); > if (unlikely(ret)) > goto err_unpin; > > diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c b/drivers/gpu/drm/i915/gt/intel_timeline.c > index 87716529cd2f..465f87b65901 100644 > --- a/drivers/gpu/drm/i915/gt/intel_timeline.c > +++ b/drivers/gpu/drm/i915/gt/intel_timeline.c > @@ -308,7 +308,7 @@ int intel_timeline_pin(struct intel_timeline *tl) > if (atomic_add_unless(&tl->pin_count, 1, 0)) > return 0; > > - err = i915_vma_pin(tl->hwsp_ggtt, 0, 0, PIN_GLOBAL | PIN_HIGH); > + err = i915_ggtt_pin(tl->hwsp_ggtt, 0, PIN_HIGH); > if (err) > return err; > > @@ -431,7 +431,7 @@ __intel_timeline_get_seqno(struct intel_timeline *tl, > goto err_rollback; > } > > - err = i915_vma_pin(vma, 0, 0, PIN_GLOBAL | PIN_HIGH); > + err = i915_ggtt_pin(vma, 0, PIN_HIGH); > if (err) { > __idle_hwsp_free(vma->private, cacheline); > goto err_rollback; > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc.c > index 5d00a3b2d914..c4c1523da7a6 100644 > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.c > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.c > @@ -678,8 +678,8 @@ struct i915_vma *intel_guc_allocate_vma(struct intel_guc *guc, u32 size) > if (IS_ERR(vma)) > goto err; > > - flags = PIN_GLOBAL | PIN_OFFSET_BIAS | i915_ggtt_pin_bias(vma); > - ret = i915_vma_pin(vma, 0, 0, flags); > + flags = PIN_OFFSET_BIAS | i915_ggtt_pin_bias(vma); > + ret = i915_ggtt_pin(vma, 0, flags); > if (ret) { > vma = ERR_PTR(ret); > goto err; > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c > index ff79da5657f8..dda1a0365f39 100644 > --- a/drivers/gpu/drm/i915/i915_gem.c > +++ b/drivers/gpu/drm/i915/i915_gem.c > @@ -1009,6 +1009,12 @@ i915_gem_object_ggtt_pin(struct drm_i915_gem_object *obj, > if (ret) > return ERR_PTR(ret); > > + ret = i915_vma_wait_for_bind(vma); > + if (ret) { > + i915_vma_unpin(vma); > + return ERR_PTR(ret); > + } > + > return vma; > } > > diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c > index 84e03da0d5f9..f11abd9553e8 100644 > --- a/drivers/gpu/drm/i915/i915_vma.c > +++ b/drivers/gpu/drm/i915/i915_vma.c > @@ -339,6 +339,25 @@ struct i915_vma_work *i915_vma_work(void) > return vw; > } > > +int i915_vma_wait_for_bind(struct i915_vma *vma) > +{ > + int err = 0; > + > + if (!rcu_access_pointer(vma->active.excl.fence)) { > + struct dma_fence *fence; > + > + rcu_read_lock(); > + fence = dma_fence_get_rcu_safe(&vma->active.excl.fence); > + rcu_read_unlock(); > + if (fence) { > + err = dma_fence_wait(fence, MAX_SCHEDULE_TIMEOUT); > + dma_fence_put(fence); > + } > + } > + > + return err; > +} > + > /** > * i915_vma_bind - Sets up PTEs for an VMA in it's corresponding address space. > * @vma: VMA to map > @@ -977,8 +996,14 @@ int i915_ggtt_pin(struct i915_vma *vma, u32 align, unsigned int flags) > > do { > err = i915_vma_pin(vma, 0, align, flags | PIN_GLOBAL); > - if (err != -ENOSPC) > + if (err != -ENOSPC) { > + if (!err) { > + err = i915_vma_wait_for_bind(vma); > + if (err) > + i915_vma_unpin(vma); > + } > return err; > + } > > /* Unlike i915_vma_pin, we don't take no for an answer! */ > flush_idle_contexts(vm->gt); > diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h > index 02b31a62951e..e1ced1df13e1 100644 > --- a/drivers/gpu/drm/i915/i915_vma.h > +++ b/drivers/gpu/drm/i915/i915_vma.h > @@ -375,6 +375,8 @@ struct i915_vma *i915_vma_make_unshrinkable(struct i915_vma *vma); > void i915_vma_make_shrinkable(struct i915_vma *vma); > void i915_vma_make_purgeable(struct i915_vma *vma); > > +int i915_vma_wait_for_bind(struct i915_vma *vma); > + > static inline int i915_vma_sync(struct i915_vma *vma) > { > /* Wait for the asynchronous bindings and pending GPU reads */ > -- > 2.25.0 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
