From 99013b10100c4b552eec845ee2ca5604c8332e92 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 10 Sep 2019 22:22:04 +0100 Subject: [PATCH] drm/i915: Make shrink/unshrink be atomic Add an atomic counter and always take the spinlock around the pin/unpin events, so that we can perform the list manipulation concurrently. Signed-off-by: Chris Wilson Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20190910212204.17190-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/gem/i915_gem_domain.c | 3 +- .../gpu/drm/i915/gem/i915_gem_object_types.h | 1 + drivers/gpu/drm/i915/gem/i915_gem_pages.c | 1 + drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 36 +++++++++++-------- drivers/gpu/drm/i915/gt/intel_context.c | 2 +- 5 files changed, 26 insertions(+), 17 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c index da3e7cf12aa1..55c3ab59e3aa 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c @@ -494,7 +494,8 @@ static void i915_gem_object_bump_inactive_ggtt(struct drm_i915_gem_object *obj) spin_lock_irqsave(&i915->mm.obj_lock, flags); - if (obj->mm.madv == I915_MADV_WILLNEED) + if (obj->mm.madv == I915_MADV_WILLNEED && + !atomic_read(&obj->mm.shrink_pin)) list_move_tail(&obj->mm.link, &i915->mm.shrink_list); spin_unlock_irqrestore(&i915->mm.obj_lock, flags); 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 a558edf15ec8..d695f187b790 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h @@ -156,6 +156,7 @@ struct drm_i915_gem_object { struct { struct mutex lock; /* protects the pages and their use */ atomic_t pages_pin_count; + atomic_t shrink_pin; struct sg_table *pages; void *mapping; diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c index 18f0ce0135c1..2e941f093a20 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c @@ -71,6 +71,7 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj, 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); } } diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c index 4e55cfc2b0dc..d2c05d752909 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c @@ -516,46 +516,52 @@ void i915_gem_shrinker_taints_mutex(struct drm_i915_private *i915, 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 (!list_empty(&obj->mm.link)) { /* pinned by caller */ - struct drm_i915_private *i915 = obj_to_i915(obj); - unsigned long flags; - - spin_lock_irqsave(&i915->mm.obj_lock, flags); - GEM_BUG_ON(list_empty(&obj->mm.link)); + if (atomic_add_unless(&obj->mm.shrink_pin, 1, 0)) + return; + spin_lock_irqsave(&i915->mm.obj_lock, flags); + if (!atomic_fetch_inc(&obj->mm.shrink_pin) && + !list_empty(&obj->mm.link)) { list_del_init(&obj->mm.link); i915->mm.shrink_count--; i915->mm.shrink_memory -= obj->base.size; - - spin_unlock_irqrestore(&i915->mm.obj_lock, flags); } + spin_unlock_irqrestore(&i915->mm.obj_lock, flags); } static void __i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj, struct list_head *head) { + struct drm_i915_private *i915 = obj_to_i915(obj); + unsigned long flags; + GEM_BUG_ON(!i915_gem_object_has_pages(obj)); - GEM_BUG_ON(!list_empty(&obj->mm.link)); + if (!i915_gem_object_is_shrinkable(obj)) + return; - if (i915_gem_object_is_shrinkable(obj)) { - struct drm_i915_private *i915 = obj_to_i915(obj); - unsigned long flags; + 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)); + 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); i915->mm.shrink_count++; i915->mm.shrink_memory += obj->base.size; - spin_unlock_irqrestore(&i915->mm.obj_lock, flags); } + spin_unlock_irqrestore(&i915->mm.obj_lock, flags); } void i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj) diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c index f55691d151ae..c0495811f493 100644 --- a/drivers/gpu/drm/i915/gt/intel_context.c +++ b/drivers/gpu/drm/i915/gt/intel_context.c @@ -134,8 +134,8 @@ static int __context_pin_state(struct i915_vma *vma) static void __context_unpin_state(struct i915_vma *vma) { - __i915_vma_unpin(vma); i915_vma_make_shrinkable(vma); + __i915_vma_unpin(vma); } static void __intel_context_retire(struct i915_active *active) -- 2.20.1