Commit ef398881 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gem: Limit struct_mutex to eb_reserve 

We only need to serialise the multiple pinning during the eb_reserve
phase. Ideally this would be using the vm->mutex as an outer lock, or
using a composite global mutex (ww_mutex), but at the moment we are
using struct_mutex for the group.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/1381


Fixes: 003d8b91 ("drm/i915/gem: Only call eb_lookup_vma once during execbuf ioctl")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: default avatarMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200306071614.2846708-3-chris@chris-wilson.co.uk
parent 26fc4e4b

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c

+20 −31
Original line number Diff line number Diff line
@@ -611,7 +611,7 @@ static int eb_reserve(struct i915_execbuffer *eb) 
	struct list_head last;

	struct eb_vma *ev;

	unsigned int i, pass;

	int err;

	int err = 0;



	/*

	 * Attempt to pin all of the buffers into the GTT.
@@ -627,8 +627,10 @@ static int eb_reserve(struct i915_execbuffer *eb) 
	 * room for the earlier objects *unless* we need to defragment.

	 */



	if (mutex_lock_interruptible(&eb->i915->drm.struct_mutex))

		return -EINTR;



	pass = 0;

	err = 0;

	do {

		list_for_each_entry(ev, &eb->unbound, bind_link) {

			err = eb_reserve_vma(eb, ev, pin_flags);
@@ -636,7 +638,7 @@ static int eb_reserve(struct i915_execbuffer *eb) 
				break;

		}

		if (!(err == -ENOSPC || err == -EAGAIN))

			return err;

			break;



		/* Resort *all* the objects into priority order */

		INIT_LIST_HEAD(&eb->unbound);
@@ -667,7 +669,9 @@ static int eb_reserve(struct i915_execbuffer *eb) 
		list_splice_tail(&last, &eb->unbound);



		if (err == -EAGAIN) {

			mutex_unlock(&eb->i915->drm.struct_mutex);

			flush_workqueue(eb->i915->mm.userptr_wq);

			mutex_lock(&eb->i915->drm.struct_mutex);

			continue;

		}
@@ -681,15 +685,20 @@ static int eb_reserve(struct i915_execbuffer *eb) 
			err = i915_gem_evict_vm(eb->context->vm);

			mutex_unlock(&eb->context->vm->mutex);

			if (err)

				return err;

				goto unlock;

			break;



		default:

			return -ENOSPC;

			err = -ENOSPC;

			goto unlock;

		}



		pin_flags = PIN_USER;

	} while (1);



unlock:

	mutex_unlock(&eb->i915->drm.struct_mutex);

	return err;

}



static unsigned int eb_batch_index(const struct i915_execbuffer *eb)
@@ -1632,7 +1641,6 @@ static int eb_prefault_relocations(const struct i915_execbuffer *eb) 


static noinline int eb_relocate_slow(struct i915_execbuffer *eb)

{

	struct drm_device *dev = &eb->i915->drm;

	bool have_copy = false;

	struct eb_vma *ev;

	int err = 0;
@@ -1643,8 +1651,6 @@ repeat: 
		goto out;

	}



	mutex_unlock(&dev->struct_mutex);



	/*

	 * We take 3 passes through the slowpatch.

	 *
@@ -1667,21 +1673,8 @@ repeat: 
		cond_resched();

		err = 0;

	}

	if (err) {

		mutex_lock(&dev->struct_mutex);

		goto out;

	}



	/* A frequent cause for EAGAIN are currently unavailable client pages */

	flush_workqueue(eb->i915->mm.userptr_wq);



	err = i915_mutex_lock_interruptible(dev);

	if (err) {

		mutex_lock(&dev->struct_mutex);

	if (err)

		goto out;

	}



	GEM_BUG_ON(!eb->batch);



	list_for_each_entry(ev, &eb->relocs, reloc_link) {

		if (!have_copy) {
@@ -1739,9 +1732,11 @@ static int eb_relocate(struct i915_execbuffer *eb) 
	if (err)

		return err;



	if (!list_empty(&eb->unbound)) {

		err = eb_reserve(eb);

		if (err)

			return err;

	}



	/* The objects are in their final locations, apply the relocations. */

	if (eb->args->flags & __EXEC_HAS_RELOC) {
@@ -2691,10 +2686,6 @@ i915_gem_do_execbuffer(struct drm_device *dev, 
	if (unlikely(err))

		goto err_context;



	err = i915_mutex_lock_interruptible(dev);

	if (err)

		goto err_engine;



	err = eb_relocate(&eb);

	if (err) {

		/*
@@ -2838,8 +2829,6 @@ err_vma: 
		eb_release_vmas(&eb);

	if (eb.trampoline)

		i915_vma_unpin(eb.trampoline);

	mutex_unlock(&dev->struct_mutex);

err_engine:

	eb_unpin_engine(&eb);

err_context:

	i915_gem_context_put(eb.gem_context);

drivers/gpu/drm/i915/i915_drv.h

+0 −6
Original line number Diff line number Diff line
@@ -1734,12 +1734,6 @@ int i915_gem_object_unbind(struct drm_i915_gem_object *obj, 


void i915_gem_runtime_suspend(struct drm_i915_private *dev_priv);



static inline int __must_check

i915_mutex_lock_interruptible(struct drm_device *dev)

{

	return mutex_lock_interruptible(&dev->struct_mutex);

}



int i915_gem_dumb_create(struct drm_file *file_priv,

			 struct drm_device *dev,

			 struct drm_mode_create_dumb *args);

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