From: Jérôme Glisse <[email protected]> When range of virtual address is updated read only and corresponding user ptr object are already read only it is pointless to do anything. Optimize this case out.
Signed-off-by: Jérôme Glisse <[email protected]> Cc: Christian König <[email protected]> Cc: Jan Kara <[email protected]> Cc: Felix Kuehling <[email protected]> Cc: Jason Gunthorpe <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Ross Zwisler <[email protected]> Cc: Dan Williams <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Radim Krčmář <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Ralph Campbell <[email protected]> Cc: John Hubbard <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: Arnd Bergmann <[email protected]> --- drivers/gpu/drm/i915/i915_gem_userptr.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index 9558582c105e..23330ac3d7ea 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -59,6 +59,7 @@ struct i915_mmu_object { struct interval_tree_node it; struct list_head link; struct work_struct work; + bool read_only; bool attached; }; @@ -119,6 +120,7 @@ static int i915_gem_userptr_mn_invalidate_range_start(struct mmu_notifier *_mn, container_of(_mn, struct i915_mmu_notifier, mn); struct i915_mmu_object *mo; struct interval_tree_node *it; + bool update_to_read_only; LIST_HEAD(cancelled); unsigned long end; @@ -128,6 +130,8 @@ static int i915_gem_userptr_mn_invalidate_range_start(struct mmu_notifier *_mn, /* interval ranges are inclusive, but invalidate range is exclusive */ end = range->end - 1; + update_to_read_only = mmu_notifier_range_update_to_read_only(range); + spin_lock(&mn->lock); it = interval_tree_iter_first(&mn->objects, range->start, end); while (it) { @@ -145,6 +149,17 @@ static int i915_gem_userptr_mn_invalidate_range_start(struct mmu_notifier *_mn, * object if it is not in the process of being destroyed. */ mo = container_of(it, struct i915_mmu_object, it); + + /* + * If it is already read only and we are updating to + * read only then we do not need to change anything. + * So save time and skip this one. + */ + if (update_to_read_only && mo->read_only) { + it = interval_tree_iter_next(it, range->start, end); + continue; + } + if (kref_get_unless_zero(&mo->obj->base.refcount)) queue_work(mn->wq, &mo->work); @@ -270,6 +285,7 @@ i915_gem_userptr_init__mmu_notifier(struct drm_i915_gem_object *obj, mo->mn = mn; mo->obj = obj; mo->it.start = obj->userptr.ptr; + mo->read_only = i915_gem_object_is_readonly(obj); mo->it.last = obj->userptr.ptr + obj->base.size - 1; INIT_WORK(&mo->work, cancel_userptr); -- 2.17.2
