On 18/01/2019 14:01, Chris Wilson wrote:
Previously, our view has been always to run the engines independently
within a context. (Multiple engines happened before we had contexts and
timelines, so they always operated independently and that behaviour
persisted into contexts.) However, at the user level the context often
represents a single timeline (e.g. GL contexts) and userspace must
ensure that the individual engines are serialised to present that
ordering to the client (or forgot about this detail entirely and hope no
one notices - a fair ploy if the client can only directly control one
engine themselves ;)
In the next patch, we will want to construct a set of engines that
operate as one, that have a single timeline interwoven between them, to
present a single virtual engine to the user. (They submit to the virtual
engine, then we decide which engine to execute on based.)
To that end, we want to be able to create contexts which have a single
timeline (fence context) shared between all engines, rather than multiple
timelines.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_context.c | 33 +++++++++++++---
drivers/gpu/drm/i915/i915_gem_context.h | 3 ++
drivers/gpu/drm/i915/i915_request.c | 10 ++++-
drivers/gpu/drm/i915/i915_request.h | 5 ++-
drivers/gpu/drm/i915/i915_sw_fence.c | 39 ++++++++++++++++---
drivers/gpu/drm/i915/i915_sw_fence.h | 13 ++++++-
drivers/gpu/drm/i915/intel_lrc.c | 5 ++-
.../gpu/drm/i915/selftests/i915_gem_context.c | 17 ++++----
drivers/gpu/drm/i915/selftests/mock_context.c | 2 +-
include/uapi/drm/i915_drm.h | 1 +
10 files changed, 103 insertions(+), 25 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index ec5e3e1c6402..e28be242399d 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -225,6 +225,9 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
ce->ops->destroy(ce);
}
+ if (ctx->timeline)
+ i915_timeline_put(ctx->timeline);
+
kfree(ctx->name);
put_pid(ctx->pid);
@@ -425,12 +428,17 @@ static void __set_ppgtt(struct i915_gem_context *ctx,
static struct i915_gem_context *
i915_gem_create_context(struct drm_i915_private *dev_priv,
- struct drm_i915_file_private *file_priv)
+ struct drm_i915_file_private *file_priv,
+ unsigned int flags)
{
struct i915_gem_context *ctx;
lockdep_assert_held(&dev_priv->drm.struct_mutex);
+ if (flags & I915_GEM_CONTEXT_SINGLE_TIMELINE &&
+ !HAS_EXECLISTS(dev_priv))
+ return ERR_PTR(-EINVAL);
+
/* Reap the most stale context */
contexts_free_first(dev_priv);
@@ -453,6 +461,18 @@ i915_gem_create_context(struct drm_i915_private *dev_priv,
i915_ppgtt_put(ppgtt);
}
+ if (flags & I915_GEM_CONTEXT_SINGLE_TIMELINE) {
+ struct i915_timeline *timeline;
+
+ timeline = i915_timeline_create(dev_priv, ctx->name, NULL);
+ if (IS_ERR(timeline)) {
+ __destroy_hw_context(ctx, file_priv);
+ return ERR_CAST(timeline);
+ }
+
+ ctx->timeline = timeline;
+ }
+
trace_i915_context_create(ctx);
return ctx;
@@ -481,7 +501,7 @@ i915_gem_context_create_gvt(struct drm_device *dev)
if (ret)
return ERR_PTR(ret);
- ctx = i915_gem_create_context(to_i915(dev), NULL);
+ ctx = i915_gem_create_context(to_i915(dev), NULL, 0);
if (IS_ERR(ctx))
goto out;
@@ -517,7 +537,7 @@ i915_gem_context_create_kernel(struct drm_i915_private *i915, int prio)
struct i915_gem_context *ctx;
int err;
- ctx = i915_gem_create_context(i915, NULL);
+ ctx = i915_gem_create_context(i915, NULL, 0);
if (IS_ERR(ctx))
return ctx;
@@ -638,7 +658,7 @@ int i915_gem_context_open(struct drm_i915_private *i915,
idr_init_base(&file_priv->vm_idr, 1);
mutex_lock(&i915->drm.struct_mutex);
- ctx = i915_gem_create_context(i915, file_priv);
+ ctx = i915_gem_create_context(i915, file_priv, 0);
mutex_unlock(&i915->drm.struct_mutex);
if (IS_ERR(ctx)) {
idr_destroy(&file_priv->context_idr);
@@ -992,7 +1012,8 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
if (!DRIVER_CAPS(dev_priv)->has_logical_contexts)
return -ENODEV;
- if (args->flags)
+ if (args->flags &
+ ~(I915_GEM_CONTEXT_SINGLE_TIMELINE))
return -EINVAL;
if (client_is_banned(file_priv)) {
@@ -1007,7 +1028,7 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
if (ret)
return ret;
- ctx = i915_gem_create_context(dev_priv, file_priv);
+ ctx = i915_gem_create_context(dev_priv, file_priv, args->flags);
mutex_unlock(&dev->struct_mutex);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
diff --git a/drivers/gpu/drm/i915/i915_gem_context.h b/drivers/gpu/drm/i915/i915_gem_context.h
index 9786f86b659d..b3a840747330 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -41,6 +41,7 @@ struct drm_i915_private;
struct drm_i915_file_private;
struct i915_hw_ppgtt;
struct i915_request;
+struct i915_timeline;
struct i915_vma;
struct intel_ring;
@@ -66,6 +67,8 @@ struct i915_gem_context {
/** file_priv: owning file descriptor */
struct drm_i915_file_private *file_priv;
+ struct i915_timeline *timeline;
+
/**
* @ppgtt: unique address space (GTT)
*
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 7bccf578cd65..ca432d3d8211 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -860,8 +860,14 @@ void i915_request_add(struct i915_request *request)
prev = i915_gem_active_raw(&timeline->last_request,
&request->i915->drm.struct_mutex);
if (prev && !i915_request_completed(prev)) {
- i915_sw_fence_await_sw_fence(&request->submit, &prev->submit,
- &request->submitq);
+ if (prev->engine == engine)
+ i915_sw_fence_await_sw_fence(&request->submit,
+ &prev->submit,
+ &request->submitq);
+ else
+ __i915_sw_fence_await_dma_fence(&request->submit,
+ &prev->fence,
+ &request->dmaq);
Drop a comment here explaining this trick, at least I always forget the
many different await flavours.
The subtlety of why we need a special flavour here of await helpers
which use the builtin call back storage, vs using the existing ones
which allocate that, totally escapes me at the moment.
It's probably a good idea to put a paragraph in the commit message
explaining what new sw fence facility needs to be added to implement
this and why.
if (engine->schedule)
__i915_sched_node_add_dependency(&request->sched,
&prev->sched,
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 679b4663f774..f715384ff485 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -108,7 +108,10 @@ struct i915_request {
* It is used by the driver to then queue the request for execution.
*/
struct i915_sw_fence submit;
- wait_queue_entry_t submitq;
+ union {
+ wait_queue_entry_t submitq;
+ struct i915_sw_dma_fence_cb dmaq;
+ };
Union deserves a comment as well I think, like this is for that and that
is for this, and only one can be in use at a time because of the third
thing.
/*
* A list of everyone we wait upon, and everyone who waits upon us.
diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
index 7c58b049ecb5..7bb64437dbbe 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.c
+++ b/drivers/gpu/drm/i915/i915_sw_fence.c
@@ -359,11 +359,6 @@ int i915_sw_fence_await_sw_fence_gfp(struct i915_sw_fence *fence,
return __i915_sw_fence_await_sw_fence(fence, signaler, NULL, gfp);
}
-struct i915_sw_dma_fence_cb {
- struct dma_fence_cb base;
- struct i915_sw_fence *fence;
-};
-
struct i915_sw_dma_fence_cb_timer {
struct i915_sw_dma_fence_cb base;
struct dma_fence *dma;
@@ -480,6 +475,40 @@ int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
return ret;
}
+static void __dma_i915_sw_fence_wake(struct dma_fence *dma,
+ struct dma_fence_cb *data)
+{
+ struct i915_sw_dma_fence_cb *cb = container_of(data, typeof(*cb), base);
+
+ i915_sw_fence_complete(cb->fence);
+}
+
+int __i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
+ struct dma_fence *dma,
+ struct i915_sw_dma_fence_cb *cb)
+{
+ int ret;
+
+ debug_fence_assert(fence);
+
+ if (dma_fence_is_signaled(dma))
+ return 0;
+
+ cb->fence = fence;
+ i915_sw_fence_await(fence);
+
+ ret = dma_fence_add_callback(dma, &cb->base, __dma_i915_sw_fence_wake);
+ if (ret == 0) {
+ ret = 1;
+ } else {
+ i915_sw_fence_complete(fence);
+ if (ret == -ENOENT) /* fence already signaled */
+ ret = 0;
+ }
+
+ return ret;
+}
+
int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
struct reservation_object *resv,
const struct dma_fence_ops *exclude,
diff --git a/drivers/gpu/drm/i915/i915_sw_fence.h b/drivers/gpu/drm/i915/i915_sw_fence.h
index 0e055ea0179f..b420ceadb813 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.h
+++ b/drivers/gpu/drm/i915/i915_sw_fence.h
@@ -9,14 +9,13 @@
#ifndef _I915_SW_FENCE_H_
#define _I915_SW_FENCE_H_
+#include <linux/dma-fence.h>
#include <linux/gfp.h>
#include <linux/kref.h>
#include <linux/notifier.h> /* for NOTIFY_DONE */
#include <linux/wait.h>
struct completion;
-struct dma_fence;
-struct dma_fence_ops;
struct reservation_object;
struct i915_sw_fence {
@@ -68,10 +67,20 @@ int i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence,
int i915_sw_fence_await_sw_fence_gfp(struct i915_sw_fence *fence,
struct i915_sw_fence *after,
gfp_t gfp);
+
+struct i915_sw_dma_fence_cb {
+ struct dma_fence_cb base;
+ struct i915_sw_fence *fence;
+};
+
+int __i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
+ struct dma_fence *dma,
+ struct i915_sw_dma_fence_cb *cb);
int i915_sw_fence_await_dma_fence(struct i915_sw_fence *fence,
struct dma_fence *dma,
unsigned long timeout,
gfp_t gfp);
+
int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
struct reservation_object *resv,
const struct dma_fence_ops *exclude,
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 323341e9bf2d..10c42820bb46 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -2644,7 +2644,10 @@ static int execlists_context_deferred_alloc(struct i915_gem_context *ctx,
goto error_deref_obj;
}
- timeline = i915_timeline_create(ctx->i915, ctx->name, NULL);
+ if (ctx->timeline)
+ timeline = i915_timeline_get(ctx->timeline);
+ else
+ timeline = i915_timeline_create(ctx->i915, ctx->name, NULL);
if (IS_ERR(timeline)) {
ret = PTR_ERR(timeline);
goto error_deref_obj;
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_context.c b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
index 2864cfb82325..3e68c2888b9c 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_context.c
@@ -143,7 +143,7 @@ static int live_nop_switch(void *arg)
}
for (n = 0; n < nctx; n++) {
- ctx[n] = i915_gem_create_context(i915, file->driver_priv);
+ ctx[n] = i915_gem_create_context(i915, file->driver_priv, 0);
if (IS_ERR(ctx[n])) {
err = PTR_ERR(ctx[n]);
goto out_unlock;
@@ -601,7 +601,8 @@ static int igt_ctx_exec(void *arg)
struct i915_gem_context *ctx;
intel_wakeref_t wakeref;
- ctx = i915_gem_create_context(i915, file->driver_priv);
+ ctx = i915_gem_create_context(i915,
+ file->driver_priv, 0);
if (IS_ERR(ctx)) {
err = PTR_ERR(ctx);
goto out_unlock;
@@ -698,7 +699,8 @@ static int igt_shared_ctx_exec(void *arg)
if (err)
goto out_unlock;
- parent = i915_gem_create_context(i915, file->driver_priv);
+ parent = i915_gem_create_context(i915,
+ file->driver_priv, 0);
if (IS_ERR(parent)) {
err = PTR_ERR(parent);
if (err == -ENODEV) /* no logical ctx support */
@@ -720,7 +722,8 @@ static int igt_shared_ctx_exec(void *arg)
if (ctx)
__destroy_hw_context(ctx, file->driver_priv);
- ctx = i915_gem_create_context(i915, file->driver_priv);
+ ctx = i915_gem_create_context(i915,
+ file->driver_priv, 0);
if (IS_ERR(ctx)) {
err = PTR_ERR(ctx);
goto out_unlock;
@@ -813,7 +816,7 @@ static int igt_ctx_readonly(void *arg)
if (err)
goto out_unlock;
- ctx = i915_gem_create_context(i915, file->driver_priv);
+ ctx = i915_gem_create_context(i915, file->driver_priv, 0);
if (IS_ERR(ctx)) {
err = PTR_ERR(ctx);
goto out_unlock;
@@ -1139,13 +1142,13 @@ static int igt_vm_isolation(void *arg)
if (err)
goto out_unlock;
- ctx_a = i915_gem_create_context(i915, file->driver_priv);
+ ctx_a = i915_gem_create_context(i915, file->driver_priv, 0);
if (IS_ERR(ctx_a)) {
err = PTR_ERR(ctx_a);
goto out_unlock;
}
- ctx_b = i915_gem_create_context(i915, file->driver_priv);
+ ctx_b = i915_gem_create_context(i915, file->driver_priv, 0);
if (IS_ERR(ctx_b)) {
err = PTR_ERR(ctx_b);
goto out_unlock;
diff --git a/drivers/gpu/drm/i915/selftests/mock_context.c b/drivers/gpu/drm/i915/selftests/mock_context.c
index b9fd2a4b95e9..f13f9c726034 100644
--- a/drivers/gpu/drm/i915/selftests/mock_context.c
+++ b/drivers/gpu/drm/i915/selftests/mock_context.c
@@ -99,7 +99,7 @@ live_context(struct drm_i915_private *i915, struct drm_file *file)
{
lockdep_assert_held(&i915->drm.struct_mutex);
- return i915_gem_create_context(i915, file->driver_priv);
+ return i915_gem_create_context(i915, file->driver_priv, 0);
}
struct i915_gem_context *
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 704e9d2fe2d6..72749dc9801e 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1444,6 +1444,7 @@ struct drm_i915_gem_context_create {
struct drm_i915_gem_context_create_ext {
__u32 ctx_id; /* output: id of new context*/
__u32 flags;
+#define I915_GEM_CONTEXT_SINGLE_TIMELINE 0x1
And some kernel doc please.
__u64 extensions;
};
Look fine, no complaints, apart from needing help to remind me how some
things work.
Regards,
Tvrtko
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