On 08-12-2021 13:07, Matthew Auld wrote:
> On Mon, 29 Nov 2021 at 13:58, Maarten Lankhorst
> <maarten.lankhorst@xxxxxxxxxxxxxxx> wrote:
>> i915_gem_execbuf will call i915_gem_evict_vm() after failing to pin
>> all objects in the first round. We are about to remove those short-term
>> pins, but even without those the objects are still locked. Add a special
>> case to allow i915_gem_evict_vm to evict locked objects as well.
>>
>> This might also allow multiple objects sharing the same resv to be evicted.
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
> Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
>
> Do we need similar treatment for stuff like evict_for_node etc?
Unfortunately not, we would risk evicting newly bound objects when we completely drop short term pinning
evict_vm is the exception, because you expect it to clean up the entire vm as much as possible, and is called explictly, not as a part of pinning. :)
>> ---
>> drivers/gpu/drm/i915/i915_gem_evict.c | 23 ++++++++++++++++++++++-
>> 1 file changed, 22 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_gem_evict.c b/drivers/gpu/drm/i915/i915_gem_evict.c
>> index 24f5e3345e43..f502a617b35c 100644
>> --- a/drivers/gpu/drm/i915/i915_gem_evict.c
>> +++ b/drivers/gpu/drm/i915/i915_gem_evict.c
>> @@ -410,21 +410,42 @@ int i915_gem_evict_vm(struct i915_address_space *vm, struct i915_gem_ww_ctx *ww)
>> do {
>> struct i915_vma *vma, *vn;
>> LIST_HEAD(eviction_list);
>> + LIST_HEAD(locked_eviction_list);
>>
>> list_for_each_entry(vma, &vm->bound_list, vm_link) {
>> if (i915_vma_is_pinned(vma))
>> continue;
>>
>> + /*
>> + * If we already own the lock, trylock fails. In case the resv
>> + * is shared among multiple objects, we still need the object ref.
>> + */
>> + if (ww && (dma_resv_locking_ctx(vma->obj->base.resv) == &ww->ctx)) {
>> + __i915_vma_pin(vma);
>> + list_add(&vma->evict_link, &locked_eviction_list);
>> + continue;
>> + }
>> +
>> if (!i915_gem_object_trylock(vma->obj, ww))
>> continue;
>>
>> __i915_vma_pin(vma);
>> list_add(&vma->evict_link, &eviction_list);
>> }
>> - if (list_empty(&eviction_list))
>> + if (list_empty(&eviction_list) && list_empty(&locked_eviction_list))
>> break;
>>
>> ret = 0;
>> + /* Unbind locked objects first, before unlocking the eviction_list */
>> + list_for_each_entry_safe(vma, vn, &locked_eviction_list, evict_link) {
>> + __i915_vma_unpin(vma);
>> +
>> + if (ret == 0)
>> + ret = __i915_vma_unbind(vma);
>> + if (ret != -EINTR) /* "Get me out of here!" */
>> + ret = 0;
>> + }
>> +
>> list_for_each_entry_safe(vma, vn, &eviction_list, evict_link) {
>> __i915_vma_unpin(vma);
>> if (ret == 0)
>> --
>> 2.34.0
>>
