Drop the atomic shrink_pin stuff, and just have make_{un}shrinkable update the shrinker visible lists immediately. This at least simplifies the next patch, and does make the behaviour more obvious. The potential downside is that make_unshrinkable now grabs a global lock even when the object itself is no longer shrinkable(transitioning from purgeable <-> shrinkable doesn't seem to be a thing), for example in the ppGTT insertion paths we should now be careful not to needlessly call make_unshrinkable multiple times. Outside of that there is some fallout in intel_context which relies on nesting calls to shrink_pin.
Signed-off-by: Matthew Auld matthew.auld@intel.com Cc: Thomas Hellström thomas.hellstrom@linux.intel.com --- drivers/gpu/drm/i915/gem/i915_gem_object.c | 9 ---- .../gpu/drm/i915/gem/i915_gem_object_types.h | 3 +- drivers/gpu/drm/i915/gem/i915_gem_pages.c | 16 +----- drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 52 +++++++++++++------ drivers/gpu/drm/i915/gt/gen6_ppgtt.c | 1 - drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 1 - drivers/gpu/drm/i915/gt/intel_context.c | 9 +--- 7 files changed, 41 insertions(+), 50 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c index 6fb9afb65034..e8265a432fcb 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c @@ -305,15 +305,6 @@ static void i915_gem_free_object(struct drm_gem_object *gem_obj) */ atomic_inc(&i915->mm.free_count);
- /* - * This serializes freeing with the shrinker. Since the free - * is delayed, first by RCU then by the workqueue, we want the - * shrinker to be able to free pages of unreferenced objects, - * or else we may oom whilst there are plenty of deferred - * freed objects. - */ - i915_gem_object_make_unshrinkable(obj); - /* * Since we require blocking on struct_mutex to unbind the freed * object from the GPU before releasing resources back to the diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h index 1b7ba859cf5e..a0069c643e3d 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h @@ -455,7 +455,6 @@ struct drm_i915_gem_object { * instead go through the pin/unpin interfaces. */ atomic_t pages_pin_count; - atomic_t shrink_pin;
/** * Priority list of potential placements for this object. @@ -516,7 +515,7 @@ struct drm_i915_gem_object { struct i915_gem_object_page_iter get_dma_page;
/** - * Element within i915->mm.unbound_list or i915->mm.bound_list, + * Element within i915->mm.shrink_list or i915->mm.purge_list, * locked by i915->mm.obj_lock. */ struct list_head link; diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c index 8eb1c3a6fc9c..f0df1394d7f6 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c @@ -64,28 +64,16 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj, GEM_BUG_ON(i915_gem_object_has_tiling_quirk(obj)); i915_gem_object_set_tiling_quirk(obj); GEM_BUG_ON(!list_empty(&obj->mm.link)); - atomic_inc(&obj->mm.shrink_pin); shrinkable = false; }
if (shrinkable) { - struct list_head *list; - unsigned long flags; - assert_object_held(obj); - spin_lock_irqsave(&i915->mm.obj_lock, flags); - - i915->mm.shrink_count++; - i915->mm.shrink_memory += obj->base.size;
if (obj->mm.madv != I915_MADV_WILLNEED) - list = &i915->mm.purge_list; + i915_gem_object_make_purgeable(obj); else - list = &i915->mm.shrink_list; - list_add_tail(&obj->mm.link, list); - - atomic_set(&obj->mm.shrink_pin, 0); - spin_unlock_irqrestore(&i915->mm.obj_lock, flags); + i915_gem_object_make_shrinkable(obj); } }
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c index 478663dc42b4..4f5d49ada9e6 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c @@ -460,23 +460,26 @@ void i915_gem_shrinker_taints_mutex(struct drm_i915_private *i915,
#define obj_to_i915(obj__) to_i915((obj__)->base.dev)
+/** + * i915_gem_object_make_unshrinkable - Hide the object from the shrinker. By + * default all object types that support shrinking(see IS_SHRINKABLE), will also + * make the object visible to the shrinker after allocating the system memory + * pages. + * @obj: The GEM object. + * + * This is typically used for special kernel internal objects that can't be + * easily processed by the shrinker, like if they are perma-pinned. + */ void i915_gem_object_make_unshrinkable(struct drm_i915_gem_object *obj) { struct drm_i915_private *i915 = obj_to_i915(obj); unsigned long flags;
- /* - * We can only be called while the pages are pinned or when - * the pages are released. If pinned, we should only be called - * from a single caller under controlled conditions; and on release - * only one caller may release us. Neither the two may cross. - */ - if (atomic_add_unless(&obj->mm.shrink_pin, 1, 0)) + if (!i915_gem_object_is_shrinkable(obj)) return;
spin_lock_irqsave(&i915->mm.obj_lock, flags); - if (!atomic_fetch_inc(&obj->mm.shrink_pin) && - !list_empty(&obj->mm.link)) { + if (!list_empty(&obj->mm.link)) { list_del_init(&obj->mm.link); i915->mm.shrink_count--; i915->mm.shrink_memory -= obj->base.size; @@ -494,28 +497,45 @@ static void __i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj, if (!i915_gem_object_is_shrinkable(obj)) return;
- if (atomic_add_unless(&obj->mm.shrink_pin, -1, 1)) - return; - spin_lock_irqsave(&i915->mm.obj_lock, flags); + GEM_BUG_ON(!kref_read(&obj->base.refcount)); - if (atomic_dec_and_test(&obj->mm.shrink_pin)) { - GEM_BUG_ON(!list_empty(&obj->mm.link));
- list_add_tail(&obj->mm.link, head); + if (list_empty(&obj->mm.link)) { i915->mm.shrink_count++; i915->mm.shrink_memory += obj->base.size; - + list_add_tail(&obj->mm.link, head); + } else { + list_move_tail(&obj->mm.link, head); } + spin_unlock_irqrestore(&i915->mm.obj_lock, flags); }
+ +/** + * i915_gem_object_make_shrinkable - Move the object to the tail of the + * shrinkable list. Objects on this list might be swapped out. Used with + * WILLNEED objects. + * @obj: The GEM object. + * + * Should only be called on objects which have backing pages. + */ void i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj) { __i915_gem_object_make_shrinkable(obj, &obj_to_i915(obj)->mm.shrink_list); }
+/** + * i915_gem_object_make_purgeable - Move the object to the tail of the purgeable + * list. Used with DONTNEED objects. Unlike with shrinkable objects, the + * shrinker will attempt to discard the backing pages, instead of trying to swap + * them out. + * @obj: The GEM object. + * + * Should only be called on objects which have backing pages. + */ void i915_gem_object_make_purgeable(struct drm_i915_gem_object *obj) { __i915_gem_object_make_shrinkable(obj, diff --git a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c index 1aee5e6b1b23..dd5ebc1659cf 100644 --- a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c +++ b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c @@ -185,7 +185,6 @@ static void gen6_alloc_va_range(struct i915_address_space *vm,
pt = stash->pt[0]; __i915_gem_object_pin_pages(pt->base); - i915_gem_object_make_unshrinkable(pt->base);
fill32_px(pt, vm->scratch[0]->encode);
diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c index 6a5af995f5b1..1b946978e377 100644 --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c @@ -301,7 +301,6 @@ static void __gen8_ppgtt_alloc(struct i915_address_space * const vm,
pt = stash->pt[!!lvl]; __i915_gem_object_pin_pages(pt->base); - i915_gem_object_make_unshrinkable(pt->base);
fill_px(pt, vm->scratch[lvl]->encode);
diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c index ff637147b1a9..1b7dc57e6ec1 100644 --- a/drivers/gpu/drm/i915/gt/intel_context.c +++ b/drivers/gpu/drm/i915/gt/intel_context.c @@ -111,11 +111,6 @@ static int __context_pin_state(struct i915_vma *vma, struct i915_gem_ww_ctx *ww) if (err) goto err_unpin;
- /* - * And mark it as a globally pinned object to let the shrinker know - * it cannot reclaim the object until we release it. - */ - i915_vma_make_unshrinkable(vma); vma->obj->mm.dirty = true;
return 0; @@ -127,7 +122,6 @@ static int __context_pin_state(struct i915_vma *vma, struct i915_gem_ww_ctx *ww)
static void __context_unpin_state(struct i915_vma *vma) { - i915_vma_make_shrinkable(vma); i915_active_release(&vma->active); __i915_vma_unpin(vma); } @@ -180,7 +174,6 @@ static int intel_context_pre_pin(struct intel_context *ce, if (err) goto err_timeline;
- return 0;
err_timeline: @@ -338,6 +331,8 @@ static void __intel_context_retire(struct i915_active *active)
set_bit(CONTEXT_VALID_BIT, &ce->flags); intel_context_post_unpin(ce); + if (ce->state) + i915_vma_make_shrinkable(ce->state); intel_context_put(ce); }