Re: [Intel-gfx] [PATCH 29/29] drm/i915/gem: Roll all of context creation together

On Thu, May 27, 2021 at 11:26:50AM -0500, Jason Ekstrand wrote:

Now that we have the whole engine set and VM at context creation time, we can just assign those fields instead of creating first and handling the VM and engines later. This lets us avoid creating useless VMs and engine sets and lets us get rid of the complex VM setting code.

Signed-off-by: Jason Ekstrand jason@jlekstrand.net

On the last three patches:

Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch

Looking at the end result we still have the ctx->user_flags which are muttable, and I think for again no reason at all. Especially for persistence I think it'd be nice to have that immutable, since some of the dedicated cleanup code for that is rather hairy.

But really also would be nice if the other 3 hang related flags would be immutable too.

Anyway that's a separate thing for sure, since the big ones are clearly the mutable vm/engines, and that's now gone.

Cheers!

I'll check with Zbyscek who cross-checks the revised igt coverage against the revised uapi. And to avoid confusion like last round: I'll expect you to ping me if you disagree on some or send out v6. Next round should already come with r-b: me on all the patches (well one maybe I need to check out again when you've moved the wrongly squashed hunk to the right place). -Daniel

---

drivers/gpu/drm/i915/gem/i915_gem_context.c | 159 ++++++------------ .../gpu/drm/i915/gem/selftests/mock_context.c | 33 ++-- 2 files changed, 64 insertions(+), 128 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index e6a6ead477ff4..502a2bd1a043e 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -1298,56 +1298,6 @@ static int __context_set_persistence(struct i915_gem_context *ctx, bool state) return 0; }

-static struct i915_gem_context * -__create_context(struct drm_i915_private *i915,

•  const struct i915_gem_proto_context *pc)
  

-{

• struct i915_gem_context *ctx;
• struct i915_gem_engines *e;
• int err;
• int i;
• ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
• if (!ctx)

• return ERR_PTR(-ENOMEM);
  

• kref_init(&ctx->ref);
• ctx->i915 = i915;
• ctx->sched = pc->sched;
• mutex_init(&ctx->mutex);
• INIT_LIST_HEAD(&ctx->link);
• spin_lock_init(&ctx->stale.lock);
• INIT_LIST_HEAD(&ctx->stale.engines);
• mutex_init(&ctx->engines_mutex);
• e = default_engines(ctx, pc->legacy_rcs_sseu);
• if (IS_ERR(e)) {

• err = PTR_ERR(e);
  

• goto err_free;
  

• }
• RCU_INIT_POINTER(ctx->engines, e);
• INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);
• mutex_init(&ctx->lut_mutex);
• /* NB: Mark all slices as needing a remap so that when the context first

• * loads it will restore whatever remap state already exists. If there
  

• * is no remap info, it will be a NOP. */
  

• ctx->remap_slice = ALL_L3_SLICES(i915);
• ctx->user_flags = pc->user_flags;
• for (i = 0; i < ARRAY_SIZE(ctx->hang_timestamp); i++)

• ctx->hang_timestamp[i] = jiffies - CONTEXT_FAST_HANG_JIFFIES;
  

• return ctx;

-err_free:

• kfree(ctx);
• return ERR_PTR(err);

-}

static inline struct i915_gem_engines * __context_engines_await(const struct i915_gem_context *ctx, bool *user_engines) @@ -1391,86 +1341,77 @@ context_apply_all(struct i915_gem_context *ctx, i915_sw_fence_complete(&e->fence); }

-static void __apply_ppgtt(struct intel_context *ce, void *vm) -{

• i915_vm_put(ce->vm);
• ce->vm = i915_vm_get(vm);

-}

-static struct i915_address_space * -__set_ppgtt(struct i915_gem_context *ctx, struct i915_address_space *vm) -{

• struct i915_address_space *old;
• old = rcu_replace_pointer(ctx->vm,

• 		  i915_vm_open(vm),
  

• 		  lockdep_is_held(&ctx->mutex));
  

• GEM_BUG_ON(old && i915_vm_is_4lvl(vm) != i915_vm_is_4lvl(old));
• context_apply_all(ctx, __apply_ppgtt, vm);
• return old;

-}

-static void __assign_ppgtt(struct i915_gem_context *ctx,

• 	   struct i915_address_space *vm)
  

-{

• if (vm == rcu_access_pointer(ctx->vm))

• return;
  

• vm = __set_ppgtt(ctx, vm);
• if (vm)

• i915_vm_close(vm);
  

-}

static struct i915_gem_context * i915_gem_create_context(struct drm_i915_private *i915, const struct i915_gem_proto_context *pc) { struct i915_gem_context *ctx;

• int ret;

• struct i915_gem_engines *e;
• int err;
• int i;

• ctx = __create_context(i915, pc);
• if (IS_ERR(ctx))

• return ctx;
  

• ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
• if (!ctx)

• return ERR_PTR(-ENOMEM);
  
  

• if (pc->vm) {

• mutex_lock(&ctx->mutex);
  

• __assign_ppgtt(ctx, pc->vm);
  

• mutex_unlock(&ctx->mutex);
  

• }

• kref_init(&ctx->ref);
• ctx->i915 = i915;
• ctx->sched = pc->sched;
• mutex_init(&ctx->mutex);
• INIT_LIST_HEAD(&ctx->link);

• if (pc->num_user_engines >= 0) {

• struct i915_gem_engines *engines;
  

• spin_lock_init(&ctx->stale.lock);
• INIT_LIST_HEAD(&ctx->stale.engines);

• engines = user_engines(ctx, pc->num_user_engines,
  

• 		       pc->user_engines);
  

• if (IS_ERR(engines)) {
  

• 	context_close(ctx);
  

• 	return ERR_CAST(engines);
  

• }
  

• if (pc->vm)

• RCU_INIT_POINTER(ctx->vm, i915_vm_open(pc->vm));
  
  

• mutex_lock(&ctx->engines_mutex);
  

• mutex_init(&ctx->engines_mutex);
• if (pc->num_user_engines >= 0) { i915_gem_context_set_user_engines(ctx);

• engines = rcu_replace_pointer(ctx->engines, engines, 1);
  

• mutex_unlock(&ctx->engines_mutex);
  

• free_engines(engines);
  

• e = user_engines(ctx, pc->num_user_engines, pc->user_engines);
  

• } else {

• i915_gem_context_clear_user_engines(ctx);
  

• e = default_engines(ctx, pc->legacy_rcs_sseu);
  

  }

• if (IS_ERR(e)) {

• err = PTR_ERR(e);
  

• goto err_vm;
  

• }

• RCU_INIT_POINTER(ctx->engines, e);

• INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);

• mutex_init(&ctx->lut_mutex);

• /* NB: Mark all slices as needing a remap so that when the context first

• * loads it will restore whatever remap state already exists. If there
  

• * is no remap info, it will be a NOP. */
  

• ctx->remap_slice = ALL_L3_SLICES(i915);

• ctx->user_flags = pc->user_flags;

• for (i = 0; i < ARRAY_SIZE(ctx->hang_timestamp); i++)

• ctx->hang_timestamp[i] = jiffies - CONTEXT_FAST_HANG_JIFFIES;
  
  

  if (pc->single_timeline) {

• ret = drm_syncobj_create(&ctx->syncobj,
  

• err = drm_syncobj_create(&ctx->syncobj,
  		 DRM_SYNCOBJ_CREATE_SIGNALED,
  		 NULL);
  

• if (ret) {
  

• 	context_close(ctx);
  

• 	return ERR_PTR(ret);
  

• }
  

• if (err)
  

• 	goto err_engines;
  

  }

  trace_i915_context_create(ctx);

  return ctx;

+err_engines:

• free_engines(e);

+err_vm:

• if (ctx->vm)

• i915_vm_close(ctx->vm);
  

• kfree(ctx);
• return ERR_PTR(err);

}

static void init_contexts(struct i915_gem_contexts *gc) diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c index 500ef27ba4771..fee070df1c97b 100644 --- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c +++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c @@ -31,15 +31,6 @@ mock_context(struct drm_i915_private *i915,

i915_gem_context_set_persistence(ctx);

• mutex_init(&ctx->engines_mutex);
• e = default_engines(ctx, null_sseu);
• if (IS_ERR(e))

• goto err_free;
  

• RCU_INIT_POINTER(ctx->engines, e);
• INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);
• mutex_init(&ctx->lut_mutex);
• if (name) { struct i915_ppgtt *ppgtt;

@@ -47,25 +38,29 @@ mock_context(struct drm_i915_private *i915,

ppgtt = mock_ppgtt(i915, name);
if (!ppgtt)

• 	goto err_put;
  

• mutex_lock(&ctx->mutex);
  

• __set_ppgtt(ctx, &ppgtt->vm);
  

• mutex_unlock(&ctx->mutex);
  

• 	goto err_free;
  
  

• ctx->vm = i915_vm_open(&ppgtt->vm);
  

  i915_vm_put(&ppgtt->vm); }

• mutex_init(&ctx->engines_mutex);

• e = default_engines(ctx, null_sseu);

• if (IS_ERR(e))

• goto err_vm;
  

• RCU_INIT_POINTER(ctx->engines, e);

• INIT_RADIX_TREE(&ctx->handles_vma, GFP_KERNEL);

• mutex_init(&ctx->lut_mutex);

• return ctx;

+err_vm:

• if (ctx->vm)

• i915_vm_close(ctx->vm);
  

err_free: kfree(ctx); return NULL;

-err_put:

• i915_gem_context_set_closed(ctx);
• i915_gem_context_put(ctx);
• return NULL;

}

void mock_context_close(struct i915_gem_context *ctx)

2.31.1

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