[Intel-gfx] [PATCH v4 15/17] drm/i915/vm_bind: Handle persistent vmas in execbuf3
Niranjana Vishwanathapura
niranjana.vishwanathapura at intel.com
Wed Oct 19 05:17:56 UTC 2022
On Tue, Oct 18, 2022 at 01:20:06PM -0700, Niranjana Vishwanathapura wrote:
>On Tue, Oct 18, 2022 at 07:01:57PM +0100, Matthew Auld wrote:
>>On 18/10/2022 08:16, Niranjana Vishwanathapura wrote:
>>>Handle persistent (VM_BIND) mappings during the request submission
>>>in the execbuf3 path.
>>>
>>>v2: Ensure requests wait for bindings to complete.
>>>v3: Remove short term pinning with PIN_VALIDATE flag.
>>> Individualize fences before adding to dma_resv obj.
>>>
>>>Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura at intel.com>
>>>Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
>>>---
>>> .../gpu/drm/i915/gem/i915_gem_execbuffer3.c | 208 +++++++++++++++++-
>>> 1 file changed, 207 insertions(+), 1 deletion(-)
>>>
>>>diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c
>>>index a9b4cc44bf66..8120e4c6b7da 100644
>>>--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c
>>>+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer3.c
>>>@@ -3,6 +3,7 @@
>>> * Copyright © 2022 Intel Corporation
>>> */
>>>+#include <linux/dma-fence-array.h>
>>> #include <linux/dma-resv.h>
>>> #include <linux/uaccess.h>
>>>@@ -19,6 +20,7 @@
>>> #include "i915_gem_vm_bind.h"
>>> #include "i915_trace.h"
>>>+#define __EXEC3_HAS_PIN BIT_ULL(33)
>>> #define __EXEC3_ENGINE_PINNED BIT_ULL(32)
>>> #define __EXEC3_INTERNAL_FLAGS (~0ull << 32)
>>>@@ -42,7 +44,9 @@
>>> * execlist. Hence, no support for implicit sync.
>>> *
>>> * The new execbuf3 ioctl only works in VM_BIND mode and the VM_BIND mode only
>>>- * works with execbuf3 ioctl for submission.
>>>+ * works with execbuf3 ioctl for submission. All BOs mapped on that VM (through
>>>+ * VM_BIND call) at the time of execbuf3 call are deemed required for that
>>>+ * submission.
>>> *
>>> * The execbuf3 ioctl directly specifies the batch addresses instead of as
>>> * object handles as in execbuf2 ioctl. The execbuf3 ioctl will also not
>>>@@ -58,6 +62,13 @@
>>> * So, a lot of code supporting execbuf2 ioctl, like relocations, VA evictions,
>>> * vma lookup table, implicit sync, vma active reference tracking etc., are not
>>> * applicable for execbuf3 ioctl.
>>>+ *
>>>+ * During each execbuf submission, request fence is added to all VM_BIND mapped
>>>+ * objects with DMA_RESV_USAGE_BOOKKEEP. The DMA_RESV_USAGE_BOOKKEEP usage will
>>>+ * prevent over sync (See enum dma_resv_usage). Note that DRM_I915_GEM_WAIT and
>>>+ * DRM_I915_GEM_BUSY ioctls do not check for DMA_RESV_USAGE_BOOKKEEP usage and
>>>+ * hence should not be used for end of batch check. Instead, the execbuf3
>>>+ * timeline out fence should be used for end of batch check.
>>> */
>>> /**
>>>@@ -127,6 +138,23 @@ eb_find_vma(struct i915_address_space *vm, u64 addr)
>>> return i915_gem_vm_bind_lookup_vma(vm, va);
>>> }
>>>+static void eb_scoop_unbound_vma_all(struct i915_address_space *vm)
>>>+{
>>>+ struct i915_vma *vma, *vn;
>>>+
>>>+ /**
>>>+ * Move all unbound vmas back into vm_bind_list so that they are
>>>+ * revalidated.
>>>+ */
>>>+ spin_lock(&vm->vm_rebind_lock);
>>>+ list_for_each_entry_safe(vma, vn, &vm->vm_rebind_list, vm_rebind_link) {
>>>+ list_del_init(&vma->vm_rebind_link);
>>>+ if (!list_empty(&vma->vm_bind_link))
>>>+ list_move_tail(&vma->vm_bind_link, &vm->vm_bind_list);
>>>+ }
>>>+ spin_unlock(&vm->vm_rebind_lock);
>>>+}
>>>+
>>> static int eb_lookup_vma_all(struct i915_execbuffer *eb)
>>> {
>>> unsigned int i, current_batch = 0;
>>>@@ -141,14 +169,108 @@ static int eb_lookup_vma_all(struct i915_execbuffer *eb)
>>> ++current_batch;
>>> }
>>>+ eb_scoop_unbound_vma_all(eb->context->vm);
>>>+
>>>+ return 0;
>>>+}
>>>+
>>>+static int eb_lock_vma_all(struct i915_execbuffer *eb)
>>>+{
>>>+ struct i915_address_space *vm = eb->context->vm;
>>>+ struct i915_vma *vma;
>>>+ int err;
>>>+
>>>+ err = i915_gem_object_lock(eb->context->vm->root_obj, &eb->ww);
>>>+ if (err)
>>>+ return err;
>>>+
>>>+ list_for_each_entry(vma, &vm->non_priv_vm_bind_list,
>>>+ non_priv_vm_bind_link) {
>>>+ err = i915_gem_object_lock(vma->obj, &eb->ww);
>>>+ if (err)
>>>+ return err;
>>>+ }
>>>+
>>> return 0;
>>> }
>>>+static void eb_release_persistent_vma_all(struct i915_execbuffer *eb)
>>>+{
>>>+ struct i915_address_space *vm = eb->context->vm;
>>>+ struct i915_vma *vma, *vn;
>>>+
>>>+ lockdep_assert_held(&vm->vm_bind_lock);
>>>+
>>>+ if (!(eb->args->flags & __EXEC3_HAS_PIN))
>>>+ return;
>>>+
>>>+ assert_object_held(vm->root_obj);
>>>+
>>>+ list_for_each_entry_safe(vma, vn, &vm->vm_bind_list, vm_bind_link)
>>>+ if (i915_vma_verify_bind_complete(vma))
>>>+ list_move_tail(&vma->vm_bind_link, &vm->vm_bound_list);
>>>+
>>>+ eb->args->flags &= ~__EXEC3_HAS_PIN;
>>>+}
>>>+
>>> static void eb_release_vma_all(struct i915_execbuffer *eb)
>>> {
>>>+ eb_release_persistent_vma_all(eb);
>>> eb_unpin_engine(eb);
>>> }
>>>+static int eb_reserve_fence_for_persistent_vma_all(struct i915_execbuffer *eb)
>>>+{
>>>+ struct i915_address_space *vm = eb->context->vm;
>>>+ u64 num_fences = 1;
>>>+ struct i915_vma *vma;
>>>+ int ret;
>>>+
>>>+ /* Reserve enough slots to accommodate composite fences */
>>>+ if (intel_context_is_parallel(eb->context))
>>>+ num_fences = eb->num_batches;
>>>+
>>>+ ret = dma_resv_reserve_fences(vm->root_obj->base.resv, num_fences);
>>>+ if (ret)
>>>+ return ret;
>>>+
>>>+ list_for_each_entry(vma, &vm->non_priv_vm_bind_list,
>>>+ non_priv_vm_bind_link) {
>>>+ ret = dma_resv_reserve_fences(vma->obj->base.resv, num_fences);
>>>+ if (ret)
>>>+ return ret;
>>>+ }
>>>+
>>>+ return 0;
>>>+}
>>>+
>>>+static int eb_validate_persistent_vma_all(struct i915_execbuffer *eb)
>>>+{
>>>+ struct i915_address_space *vm = eb->context->vm;
>>>+ struct i915_vma *vma;
>>>+ int ret = 0;
>>>+
>>>+ lockdep_assert_held(&vm->vm_bind_lock);
>>>+ assert_object_held(vm->root_obj);
>>>+
>>>+ ret = eb_reserve_fence_for_persistent_vma_all(eb);
>>>+ if (ret)
>>>+ return ret;
>>>+
>>>+ list_for_each_entry(vma, &vm->vm_bind_list, vm_bind_link) {
>>>+ u64 pin_flags = vma->start | PIN_OFFSET_FIXED |
>>>+ PIN_USER | PIN_VALIDATE;
>>>+
>>>+ ret = i915_vma_pin_ww(vma, &eb->ww, 0, 0, pin_flags);
>>>+ if (ret)
>>>+ break;
>>>+
>>>+ eb->args->flags |= __EXEC3_HAS_PIN;
>>>+ }
>>>+
>>>+ return ret;
>>>+}
>>>+
>>> /*
>>> * Using two helper loops for the order of which requests / batches are created
>>> * and added the to backend. Requests are created in order from the parent to
>>>@@ -160,13 +282,80 @@ static void eb_release_vma_all(struct i915_execbuffer *eb)
>>> */
>>> #define for_each_batch_create_order(_eb) \
>>> for (unsigned int i = 0; i < (_eb)->num_batches; ++i)
>>>+#define for_each_batch_add_order(_eb) \
>>>+ for (int i = (_eb)->num_batches - 1; i >= 0; --i)
>>>+
>>>+static void __eb_persistent_add_shared_fence(struct drm_i915_gem_object *obj,
>>>+ struct dma_fence *fence)
>>>+{
>>>+ struct dma_fence *curr;
>>>+ int idx;
>>>+
>>>+ dma_fence_array_for_each(curr, idx, fence)
>>>+ dma_resv_add_fence(obj->base.resv, curr,
>>>+ DMA_RESV_USAGE_BOOKKEEP);
>>>+
>>>+ obj->write_domain = 0;
>>>+ obj->read_domains |= I915_GEM_GPU_DOMAINS;
>>>+ obj->mm.dirty = true;
>>>+}
>>>+
>>>+static void eb_persistent_add_shared_fence(struct i915_execbuffer *eb)
>>>+{
>>>+ struct i915_address_space *vm = eb->context->vm;
>>>+ struct dma_fence *fence;
>>>+ struct i915_vma *vma;
>>>+
>>>+ fence = eb->composite_fence ? eb->composite_fence :
>>>+ &eb->requests[0]->fence;
>>>+
>>>+ __eb_persistent_add_shared_fence(vm->root_obj, fence);
>>>+ list_for_each_entry(vma, &vm->non_priv_vm_bind_list,
>>>+ non_priv_vm_bind_link)
>>>+ __eb_persistent_add_shared_fence(vma->obj, fence);
>>>+}
>>>+
>>>+static void eb_move_all_persistent_vma_to_active(struct i915_execbuffer *eb)
>>>+{
>>>+ /* Add fence to BOs dma-resv fence list */
>>>+ eb_persistent_add_shared_fence(eb);
>>>+}
>>> static int eb_move_to_gpu(struct i915_execbuffer *eb)
>>> {
>>>+ struct i915_address_space *vm = eb->context->vm;
>>>+ struct i915_vma *vma;
>>>+ int err = 0;
>>>+
>>>+ lockdep_assert_held(&vm->vm_bind_lock);
>>>+ assert_object_held(vm->root_obj);
>>>+
>>>+ eb_move_all_persistent_vma_to_active(eb);
>>>+
>>>+ list_for_each_entry(vma, &vm->vm_bind_list, vm_bind_link) {
>>>+ for_each_batch_add_order(eb) {
>>>+ if (!eb->requests[i])
>>>+ continue;
>>>+
>>>+ err = i915_request_await_bind(eb->requests[i], vma);
>>>+ if (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) {
>>>+ if (!eb->requests[i])
>>>+ break;
>>>+
>>>+ i915_request_set_error_once(eb->requests[i], err);
>>>+ }
>>>+ return err;
>>> }
>>> static int eb_request_submit(struct i915_execbuffer *eb,
>>>@@ -483,6 +672,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>>> mutex_lock(&eb.context->vm->vm_bind_lock);
>>>+lookup_vmas:
>>> err = eb_lookup_vma_all(&eb);
>>> if (err) {
>>> eb_release_vma_all(&eb);
>>>@@ -499,6 +689,22 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>>> /* only throttle once, even if we didn't need to throttle */
>>> throttle = false;
>>>+ err = eb_lock_vma_all(&eb);
>>>+ if (err)
>>>+ goto err_validate;
>>>+
>>>+ /**
>>>+ * No object unbinds possible once the objects are locked. So,
>>>+ * check for any unbinds here, which needs to be scooped up.
>>>+ */
>>>+ if (!list_empty(&eb.context->vm->vm_rebind_list)) {
>>>+ eb_release_vma_all(&eb);
>>>+ i915_gem_ww_ctx_fini(&eb.ww);
>>>+ goto lookup_vmas;
>>>+ }
>>
>>Is it not possible to grab the object locks first, and then move
>>stuff off the rebind_list to be re-validated? Or if not maybe a
>>comment to explain?
>>
>
>We need to do the rebind_list scooping in lookup phase of the execbuf
>path so that userptr_submit_init() can be called on them without
>holding the object lock. Object locks are held during validation phase.
>Ok, will add some documention where we invoke eb_scoop_unbound_vma_all().
>
Hmm...seems bit more complicated than that. For userptr, we have separate
userptr_invalidated_list. So, probably rebind_list can be scooped in the
validation phase under the object locks, unless there are other ways
the userptr objects gets unbound other than through mmu invalidation.
Niranjana
>Niranjana
>
>>>+
>>>+ err = eb_validate_persistent_vma_all(&eb);
>>>+
>>> err_validate:
>>> if (err == -EDEADLK) {
>>> eb_release_vma_all(&eb);
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