[Intel-gfx] [RFC 08/10] drm/i915/vm_bind: userptr dma-resv changes
Niranjana Vishwanathapura
niranjana.vishwanathapura at intel.com
Fri Jul 8 14:51:58 UTC 2022
On Thu, Jul 07, 2022 at 06:11:13AM -0700, Hellstrom, Thomas wrote:
>On Fri, 2022-07-01 at 15:50 -0700, Niranjana Vishwanathapura wrote:
>> For persistent (vm_bind) vmas of userptr BOs, handle the user
>> page pinning by using the i915_gem_object_userptr_submit_init()
>> /done() functions
>>
>> Signed-off-by: Niranjana Vishwanathapura
>> <niranjana.vishwanathapura at intel.com>
>> ---
>> .../gpu/drm/i915/gem/i915_gem_execbuffer3.c | 67
>> +++++++++++++++++++
>> .../drm/i915/gem/i915_gem_vm_bind_object.c | 16 +++++
>> drivers/gpu/drm/i915/gt/intel_gtt.c | 1 +
>> drivers/gpu/drm/i915/gt/intel_gtt.h | 1 +
>> 4 files changed, 85 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c
>> index 2079f5ca9010..bf13dd6d642e 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c
>> @@ -22,6 +22,7 @@
>> #include "i915_gem_vm_bind.h"
>> #include "i915_trace.h"
>>
>> +#define __EXEC3_USERPTR_USED BIT_ULL(34)
>> #define __EXEC3_HAS_PIN BIT_ULL(33)
>> #define __EXEC3_ENGINE_PINNED BIT_ULL(32)
>> #define __EXEC3_INTERNAL_FLAGS (~0ull << 32)
>> @@ -147,10 +148,36 @@ static void eb_scoop_unbound_vmas(struct
>> i915_address_space *vm)
>> spin_unlock(&vm->vm_rebind_lock);
>> }
>>
>> +static int eb_lookup_persistent_userptr_vmas(struct i915_execbuffer
>> *eb)
>> +{
>> + struct i915_address_space *vm = eb->context->vm;
>> + struct i915_vma *last_vma = NULL;
>> + struct i915_vma *vma;
>> + int err;
>> +
>> + assert_vm_bind_held(vm);
>> +
>> + list_for_each_entry(vma, &vm->vm_bind_list, vm_bind_link) {
>> + if (i915_gem_object_is_userptr(vma->obj)) {
>> + err =
>> i915_gem_object_userptr_submit_init(vma->obj);
>> + if (err)
>> + return err;
>> +
>> + last_vma = vma;
>> + }
>> + }
>> +
>
>Don't we need to loop also over non-private userptr objects?
No, as explained in other thread, non-private BOs will also be
there in vm_bind/bound_list.
>
>
>> + if (last_vma)
>> + eb->args->flags |= __EXEC3_USERPTR_USED;
>> +
>> + return 0;
>> +}
>> +
>> static int eb_lookup_vmas(struct i915_execbuffer *eb)
>> {
>> unsigned int i, current_batch = 0;
>> struct i915_vma *vma;
>> + int err = 0;
>>
>> for (i = 0; i < eb->num_batches; i++) {
>> vma = eb_find_vma(eb->context->vm, eb-
>> >batch_addresses[i]);
>> @@ -163,6 +190,10 @@ static int eb_lookup_vmas(struct i915_execbuffer
>> *eb)
>>
>> eb_scoop_unbound_vmas(eb->context->vm);
>>
>> + err = eb_lookup_persistent_userptr_vmas(eb);
>> + if (err)
>> + return err;
>> +
>> return 0;
>> }
>>
>> @@ -358,15 +389,51 @@ static void
>> eb_persistent_vmas_move_to_active(struct i915_execbuffer *eb)
>>
>> static int eb_move_to_gpu(struct i915_execbuffer *eb)
>> {
>> + int err = 0, j;
>> +
>> assert_vm_bind_held(eb->context->vm);
>> assert_vm_priv_held(eb->context->vm);
>>
>> eb_persistent_vmas_move_to_active(eb);
>>
>> +#ifdef CONFIG_MMU_NOTIFIER
>> + if (!err && (eb->args->flags & __EXEC3_USERPTR_USED)) {
>> + struct i915_vma *vma;
>> +
>> + assert_vm_bind_held(eb->context->vm);
>> + assert_vm_priv_held(eb->context->vm);
>> +
>> + read_lock(&eb->i915->mm.notifier_lock);
>> + list_for_each_entry(vma, &eb->context->vm-
>> >vm_bind_list,
>> + vm_bind_link) {
>> + if (!i915_gem_object_is_userptr(vma->obj))
>> + continue;
>> +
>> + err =
>> i915_gem_object_userptr_submit_done(vma->obj);
>> + if (err)
>> + break;
>> + }
>> +
>> + read_unlock(&eb->i915->mm.notifier_lock);
>> + }
>
>Since we don't loop over the vm_bound_list, there is a need to check
>whether the rebind_list is empty here under the notifier_lock in read
>mode, and in that case, restart from eb_lookup_vmas(). That might also
>eliminate the need for the __EXEC3_USERPTR_USED flag?
>
>That will also catch any objects that were evicted between
>eb_lookup_vmas() where the rebind_list was last checked, and
>i915_gem_vm_priv_lock(), which prohibits further eviction, but if we
>want to catch these earlier (which I think is a good idea), we could
>check that the rebind_list is indeed empty just after taking the
>vm_priv_lock(), and if not, restart from eb_lookup_vmas().
Yah, right, we need to check rebind_list here and if not empty, restart
from lookup phase.
It is bit tricky with userptr here as the unbind happens during
submit_init() call after we scoop unbound vmas here, the vmas gets
re-added to rebind_list :(.
I think we need a separate 'invalidated_userptr_list' here and we
iterate through it for submit_init() and submit_done() calls (yes,
__EXEC3_USERPTR_USED flag won't be needed then).
And, we call, eb_scoop_unbound_vmas() after calling
eb_lookup_persistent_userptr_vmas(), so that we scoop all unbound
vmas properly.
>
>
>> +#endif
>> +
>> + if (unlikely(err))
>> + goto err_skip;
>> +
>> /* Unconditionally flush any chipset caches (for streaming
>> writes). */
>> intel_gt_chipset_flush(eb->gt);
>>
>> return 0;
>> +
>> +err_skip:
>> + for_each_batch_create_order(eb, j) {
>> + if (!eb->requests[j])
>> + break;
>> +
>> + i915_request_set_error_once(eb->requests[j], err);
>> + }
>> + return err;
>> }
>>
>> static int eb_request_submit(struct i915_execbuffer *eb,
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>> index 1a8efa83547f..cae282b91618 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>> @@ -263,6 +263,12 @@ int i915_gem_vm_bind_obj(struct
>> i915_address_space *vm,
>> goto put_obj;
>> }
>>
>> + if (i915_gem_object_is_userptr(obj)) {
>> + ret = i915_gem_object_userptr_submit_init(obj);
>> + if (ret)
>> + goto put_obj;
>> + }
>> +
>> ret = i915_gem_vm_bind_lock_interruptible(vm);
>> if (ret)
>> goto put_obj;
>> @@ -295,6 +301,16 @@ int i915_gem_vm_bind_obj(struct
>> i915_address_space *vm,
>> /* Make it evictable */
>> __i915_vma_unpin(vma);
>>
>> +#ifdef CONFIG_MMU_NOTIFIER
>> + if (i915_gem_object_is_userptr(obj)) {
>> + write_lock(&vm->i915->mm.notifier_lock);
>
>Why do we need the lock in write mode here?
Looks like it was no intentional. Should switch to read_lock here.
Niranjana
>
>> + ret = i915_gem_object_userptr_submit_done(obj);
>> + write_unlock(&vm->i915->mm.notifier_lock);
>> + if (ret)
>> + goto out_ww;
>> + }
>> +#endif
>> +
>> list_add_tail(&vma->vm_bind_link, &vm->vm_bound_list);
>> i915_vm_bind_it_insert(vma, &vm->va);
>> if (!obj->priv_root)
>> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c
>> b/drivers/gpu/drm/i915/gt/intel_gtt.c
>> index 55d5389b2c6c..4ab3bda644ff 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_gtt.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
>> @@ -295,6 +295,7 @@ void i915_address_space_init(struct
>> i915_address_space *vm, int subclass)
>> GEM_BUG_ON(IS_ERR(vm->root_obj));
>> INIT_LIST_HEAD(&vm->vm_rebind_list);
>> spin_lock_init(&vm->vm_rebind_lock);
>> + INIT_LIST_HEAD(&vm->invalidate_link);
>> }
>>
>> void *__px_vaddr(struct drm_i915_gem_object *p)
>> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h
>> b/drivers/gpu/drm/i915/gt/intel_gtt.h
>> index fe5485c4a1cd..f9edf11c144f 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_gtt.h
>> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
>> @@ -267,6 +267,7 @@ struct i915_address_space {
>> struct list_head vm_bound_list;
>> struct list_head vm_rebind_list;
>> spinlock_t vm_rebind_lock; /* Protects vm_rebind_list */
>> + struct list_head invalidate_link;
>> /* va tree of persistent vmas */
>> struct rb_root_cached va;
>> struct list_head non_priv_vm_bind_list;
>
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