From aa653a685d816648dd903f76c14a30d8baa23933 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 4 Aug 2016 07:52:27 +0100 Subject: [PATCH] drm/i915: Be more careful when unbinding vma When we call i915_vma_unbind(), we will wait upon outstanding rendering. This will also trigger a retirement phase, which may update the object lists. If, we extend request tracking to the VMA itself (rather than keep it at the encompassing object), then there is a potential that the obj->vma_list be modified for other elements upon i915_vma_unbind(). As a result, if we walk over the object list and call i915_vma_unbind(), we need to be prepared for that list to change. Signed-off-by: Chris Wilson Reviewed-by: Tvrtko Ursulin Reviewed-by: Joonas Lahtinen Link: http://patchwork.freedesktop.org/patch/msgid/1470293567-10811-8-git-send-email-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_drv.h | 2 ++ drivers/gpu/drm/i915/i915_gem.c | 57 +++++++++++++++++++++++--------- drivers/gpu/drm/i915/i915_gem_shrinker.c | 8 +---- drivers/gpu/drm/i915/i915_gem_userptr.c | 4 +-- 4 files changed, 46 insertions(+), 25 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 7a9a2d820aca..a6bab90bf832 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -3052,6 +3052,8 @@ int __must_check i915_vma_unbind(struct i915_vma *vma); * _guarantee_ VMA in question is _not in use_ anywhere. */ int __must_check __i915_vma_unbind_no_wait(struct i915_vma *vma); + +int i915_gem_object_unbind(struct drm_i915_gem_object *obj); int i915_gem_object_put_pages(struct drm_i915_gem_object *obj); void i915_gem_release_all_mmaps(struct drm_i915_private *dev_priv); void i915_gem_release_mmap(struct drm_i915_gem_object *obj); diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 0884870272ac..a38af9e58ec5 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -283,18 +283,38 @@ static const struct drm_i915_gem_object_ops i915_gem_phys_ops = { .release = i915_gem_object_release_phys, }; +int +i915_gem_object_unbind(struct drm_i915_gem_object *obj) +{ + struct i915_vma *vma; + LIST_HEAD(still_in_list); + int ret; + + /* The vma will only be freed if it is marked as closed, and if we wait + * upon rendering to the vma, we may unbind anything in the list. + */ + while ((vma = list_first_entry_or_null(&obj->vma_list, + struct i915_vma, + obj_link))) { + list_move_tail(&vma->obj_link, &still_in_list); + ret = i915_vma_unbind(vma); + if (ret) + break; + } + list_splice(&still_in_list, &obj->vma_list); + + return ret; +} + static int drop_pages(struct drm_i915_gem_object *obj) { - struct i915_vma *vma, *next; int ret; i915_gem_object_get(obj); - list_for_each_entry_safe(vma, next, &obj->vma_list, obj_link) - if (i915_vma_unbind(vma)) - break; - - ret = i915_gem_object_put_pages(obj); + ret = i915_gem_object_unbind(obj); + if (ret == 0) + ret = i915_gem_object_put_pages(obj); i915_gem_object_put(obj); return ret; @@ -3450,8 +3470,7 @@ i915_gem_object_set_to_gtt_domain(struct drm_i915_gem_object *obj, bool write) int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj, enum i915_cache_level cache_level) { - struct drm_device *dev = obj->base.dev; - struct i915_vma *vma, *next; + struct i915_vma *vma; int ret = 0; if (obj->cache_level == cache_level) @@ -3462,7 +3481,8 @@ int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj, * catch the issue of the CS prefetch crossing page boundaries and * reading an invalid PTE on older architectures. */ - list_for_each_entry_safe(vma, next, &obj->vma_list, obj_link) { +restart: + list_for_each_entry(vma, &obj->vma_list, obj_link) { if (!drm_mm_node_allocated(&vma->node)) continue; @@ -3471,11 +3491,18 @@ int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj, return -EBUSY; } - if (!i915_gem_valid_gtt_space(vma, cache_level)) { - ret = i915_vma_unbind(vma); - if (ret) - return ret; - } + if (i915_gem_valid_gtt_space(vma, cache_level)) + continue; + + ret = i915_vma_unbind(vma); + if (ret) + return ret; + + /* As unbinding may affect other elements in the + * obj->vma_list (due to side-effects from retiring + * an active vma), play safe and restart the iterator. + */ + goto restart; } /* We can reuse the existing drm_mm nodes but need to change the @@ -3494,7 +3521,7 @@ int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj, if (ret) return ret; - if (!HAS_LLC(dev) && cache_level != I915_CACHE_NONE) { + if (!HAS_LLC(obj->base.dev) && cache_level != I915_CACHE_NONE) { /* Access to snoopable pages through the GTT is * incoherent and on some machines causes a hard * lockup. Relinquish the CPU mmaping to force diff --git a/drivers/gpu/drm/i915/i915_gem_shrinker.c b/drivers/gpu/drm/i915/i915_gem_shrinker.c index b95cd9f404f6..64d179d4f684 100644 --- a/drivers/gpu/drm/i915/i915_gem_shrinker.c +++ b/drivers/gpu/drm/i915/i915_gem_shrinker.c @@ -172,8 +172,6 @@ i915_gem_shrink(struct drm_i915_private *dev_priv, (obj = list_first_entry_or_null(phase->list, typeof(*obj), global_list))) { - struct i915_vma *vma, *v; - list_move_tail(&obj->global_list, &still_in_list); if (flags & I915_SHRINK_PURGEABLE && @@ -193,11 +191,7 @@ i915_gem_shrink(struct drm_i915_private *dev_priv, i915_gem_object_get(obj); /* For the unbound phase, this should be a no-op! */ - list_for_each_entry_safe(vma, v, - &obj->vma_list, obj_link) - if (i915_vma_unbind(vma)) - break; - + i915_gem_object_unbind(obj); if (i915_gem_object_put_pages(obj) == 0) count += obj->base.size >> PAGE_SHIFT; diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index ca8b82ab93d6..e935b327f3f9 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -104,7 +104,6 @@ static void cancel_userptr(struct work_struct *work) if (obj->pages != NULL) { struct drm_i915_private *dev_priv = to_i915(dev); - struct i915_vma *vma, *tmp; bool was_interruptible; wait_rendering(obj); @@ -112,8 +111,7 @@ static void cancel_userptr(struct work_struct *work) was_interruptible = dev_priv->mm.interruptible; dev_priv->mm.interruptible = false; - list_for_each_entry_safe(vma, tmp, &obj->vma_list, obj_link) - WARN_ON(i915_vma_unbind(vma)); + WARN_ON(i915_gem_object_unbind(obj)); WARN_ON(i915_gem_object_put_pages(obj)); dev_priv->mm.interruptible = was_interruptible; -- 2.11.0