[Intel-gfx] [RFC 05/10] drm/i915/vm_bind: Handle persistent vmas

Zeng, Oak oak.zeng at intel.com
Mon Jul 4 17:05:38 UTC 2022



Thanks,
Oak

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of
> Niranjana Vishwanathapura
> Sent: July 1, 2022 6:51 PM
> To: intel-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org
> Cc: Zanoni, Paulo R <paulo.r.zanoni at intel.com>; Hellstrom, Thomas
> <thomas.hellstrom at intel.com>; Auld, Matthew <matthew.auld at intel.com>;
> Vetter, Daniel <daniel.vetter at intel.com>; christian.koenig at amd.com
> Subject: [Intel-gfx] [RFC 05/10] drm/i915/vm_bind: Handle persistent vmas
> 
> Treat VM_BIND vmas as persistent and handle them during the request
> submission in the execbuff path.

Hi Niranjana,

Is the meaning of "persistent" above persistent across all the subsequent execbuf ioctls?

Thanks,
Oak 

> 
> Support eviction by maintaining a list of evicted persistent vmas for rebinding
> during next submission.
> 
> Signed-off-by: Niranjana Vishwanathapura
> <niranjana.vishwanathapura at intel.com>
> ---
>  drivers/gpu/drm/i915/gem/i915_gem_object.c    |  1 +
>  drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h   |  3 +
>  .../drm/i915/gem/i915_gem_vm_bind_object.c    | 12 ++-
>  drivers/gpu/drm/i915/gt/intel_gtt.c           |  2 +
>  drivers/gpu/drm/i915/gt/intel_gtt.h           |  2 +
>  drivers/gpu/drm/i915/i915_gem_gtt.h           | 22 ++++++
>  drivers/gpu/drm/i915/i915_vma.c               | 32 +++++++-
>  drivers/gpu/drm/i915/i915_vma.h               | 78 +++++++++++++++++--
>  drivers/gpu/drm/i915/i915_vma_types.h         | 23 ++++++
>  9 files changed, 163 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c
> b/drivers/gpu/drm/i915/gem/i915_gem_object.c
> index ccec4055fde3..5121f02ba95c 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
> @@ -38,6 +38,7 @@
>  #include "i915_gem_mman.h"
>  #include "i915_gem_object.h"
>  #include "i915_gem_ttm.h"
> +#include "i915_gem_vm_bind.h"
>  #include "i915_memcpy.h"
>  #include "i915_trace.h"
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
> b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
> index 849bf3c1061e..eaadf5a6ab09 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind.h
> @@ -6,6 +6,7 @@
>  #ifndef __I915_GEM_VM_BIND_H
>  #define __I915_GEM_VM_BIND_H
> 
> +#include <linux/dma-resv.h>
>  #include "i915_drv.h"
> 
>  #define assert_vm_bind_held(vm)   lockdep_assert_held(&(vm)-
> >vm_bind_lock)
> @@ -26,6 +27,8 @@ static inline void i915_gem_vm_bind_unlock(struct
> i915_address_space *vm)
>  	mutex_unlock(&vm->vm_bind_lock);
>  }
> 
> +#define assert_vm_priv_held(vm)   assert_object_held((vm)->root_obj)
> +
>  static inline int i915_gem_vm_priv_lock(struct i915_address_space *vm,
>  					struct i915_gem_ww_ctx *ww)
>  {
> 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 96f139cc8060..1a8efa83547f 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
> @@ -85,6 +85,13 @@ void i915_gem_vm_bind_remove(struct i915_vma
> *vma, bool release_obj)  {
>  	assert_vm_bind_held(vma->vm);
> 
> +	spin_lock(&vma->vm->vm_rebind_lock);
> +	if (!list_empty(&vma->vm_rebind_link))
> +		list_del_init(&vma->vm_rebind_link);
> +	i915_vma_set_purged(vma);
> +	i915_vma_set_freed(vma);
> +	spin_unlock(&vma->vm->vm_rebind_lock);
> +
>  	if (!list_empty(&vma->vm_bind_link)) {
>  		list_del_init(&vma->vm_bind_link);
>  		list_del_init(&vma->non_priv_vm_bind_link);
> @@ -220,6 +227,7 @@ static struct i915_vma *vm_bind_get_vma(struct
> i915_address_space *vm,
> 
>  	vma->start = va->start;
>  	vma->last = va->start + va->length - 1;
> +	i915_vma_set_persistent(vma);
> 
>  	return vma;
>  }
> @@ -304,8 +312,10 @@ int i915_gem_vm_bind_obj(struct
> i915_address_space *vm,
> 
>  	i915_vm_bind_put_fence(vma);
>  put_vma:
> -	if (ret)
> +	if (ret) {
> +		i915_vma_set_freed(vma);
>  		i915_vma_destroy(vma);
> +	}
> 
>  	i915_gem_ww_ctx_fini(&ww);
>  unlock_vm:
> diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c
> b/drivers/gpu/drm/i915/gt/intel_gtt.c
> index df0a8459c3c6..55d5389b2c6c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gtt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
> @@ -293,6 +293,8 @@ void i915_address_space_init(struct
> i915_address_space *vm, int subclass)
>  	INIT_LIST_HEAD(&vm->non_priv_vm_bind_list);
>  	vm->root_obj = i915_gem_object_create_internal(vm->i915,
> PAGE_SIZE);
>  	GEM_BUG_ON(IS_ERR(vm->root_obj));
> +	INIT_LIST_HEAD(&vm->vm_rebind_list);
> +	spin_lock_init(&vm->vm_rebind_lock);
>  }
> 
>  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 f538ce9115c9..fe5485c4a1cd 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gtt.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
> @@ -265,6 +265,8 @@ struct i915_address_space {
>  	struct mutex vm_bind_lock;  /* Protects vm_bind lists */
>  	struct list_head vm_bind_list;
>  	struct list_head vm_bound_list;
> +	struct list_head vm_rebind_list;
> +	spinlock_t vm_rebind_lock;   /* Protects vm_rebind_list */
>  	/* va tree of persistent vmas */
>  	struct rb_root_cached va;
>  	struct list_head non_priv_vm_bind_list; diff --git
> a/drivers/gpu/drm/i915/i915_gem_gtt.h
> b/drivers/gpu/drm/i915/i915_gem_gtt.h
> index 8c2f57eb5dda..09b89d1913fc 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.h
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
> @@ -51,4 +51,26 @@ int i915_gem_gtt_insert(struct i915_address_space
> *vm,
> 
>  #define PIN_OFFSET_MASK		I915_GTT_PAGE_MASK
> 
> +static inline int i915_vm_sync(struct i915_address_space *vm) {
> +	int ret;
> +
> +	/* Wait for all requests under this vm to finish */
> +	ret = dma_resv_wait_timeout(vm->root_obj->base.resv,
> +				    DMA_RESV_USAGE_BOOKKEEP, false,
> +				    MAX_SCHEDULE_TIMEOUT);
> +	if (ret < 0)
> +		return ret;
> +	else if (ret > 0)
> +		return 0;
> +	else
> +		return -ETIMEDOUT;
> +}
> +
> +static inline bool i915_vm_is_active(const struct i915_address_space
> +*vm) {
> +	return !dma_resv_test_signaled(vm->root_obj->base.resv,
> +				       DMA_RESV_USAGE_BOOKKEEP);
> +}
> +
>  #endif
> diff --git a/drivers/gpu/drm/i915/i915_vma.c
> b/drivers/gpu/drm/i915/i915_vma.c index 6737236b7884..6adb013579be
> 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -237,6 +237,7 @@ vma_create(struct drm_i915_gem_object *obj,
> 
>  	INIT_LIST_HEAD(&vma->vm_bind_link);
>  	INIT_LIST_HEAD(&vma->non_priv_vm_bind_link);
> +	INIT_LIST_HEAD(&vma->vm_rebind_link);
>  	return vma;
> 
>  err_unlock:
> @@ -1622,7 +1623,8 @@ void i915_vma_close(struct i915_vma *vma)
>  	if (atomic_dec_and_lock_irqsave(&vma->open_count,
>  					&gt->closed_lock,
>  					flags)) {
> -		__vma_close(vma, gt);
> +		if (!i915_vma_is_persistent(vma))
> +			__vma_close(vma, gt);
>  		spin_unlock_irqrestore(&gt->closed_lock, flags);
>  	}
>  }
> @@ -1647,6 +1649,13 @@ static void force_unbind(struct i915_vma *vma)
>  	if (!drm_mm_node_allocated(&vma->node))
>  		return;
> 
> +	/*
> +	 * Mark persistent vma as purged to avoid it waiting
> +	 * for VM to be released.
> +	 */
> +	if (i915_vma_is_persistent(vma))
> +		i915_vma_set_purged(vma);
> +
>  	atomic_and(~I915_VMA_PIN_MASK, &vma->flags);
>  	WARN_ON(__i915_vma_unbind(vma));
>  	GEM_BUG_ON(drm_mm_node_allocated(&vma->node));
> @@ -1666,9 +1675,12 @@ static void release_references(struct i915_vma
> *vma, bool vm_ddestroy)
> 
>  	spin_unlock(&obj->vma.lock);
> 
> -	i915_gem_vm_bind_lock(vma->vm);
> -	i915_gem_vm_bind_remove(vma, true);
> -	i915_gem_vm_bind_unlock(vma->vm);
> +	if (i915_vma_is_persistent(vma) &&
> +	    !i915_vma_is_freed(vma)) {
> +		i915_gem_vm_bind_lock(vma->vm);
> +		i915_gem_vm_bind_remove(vma, true);
> +		i915_gem_vm_bind_unlock(vma->vm);
> +	}
> 
>  	spin_lock_irq(&gt->closed_lock);
>  	__i915_vma_remove_closed(vma);
> @@ -1839,6 +1851,8 @@ int _i915_vma_move_to_active(struct i915_vma
> *vma,
>  	int err;
> 
>  	assert_object_held(obj);
> +	if (i915_vma_is_persistent(vma))
> +		return -EINVAL;
> 
>  	GEM_BUG_ON(!vma->pages);
> 
> @@ -1999,6 +2013,16 @@ int __i915_vma_unbind(struct i915_vma *vma)
>  	__i915_vma_evict(vma, false);
> 
>  	drm_mm_remove_node(&vma->node); /* pairs with
> i915_vma_release() */
> +
> +	if (i915_vma_is_persistent(vma)) {
> +		spin_lock(&vma->vm->vm_rebind_lock);
> +		if (list_empty(&vma->vm_rebind_link) &&
> +		    !i915_vma_is_purged(vma))
> +			list_add_tail(&vma->vm_rebind_link,
> +				      &vma->vm->vm_rebind_list);
> +		spin_unlock(&vma->vm->vm_rebind_lock);
> +	}
> +
>  	return 0;
>  }
> 
> diff --git a/drivers/gpu/drm/i915/i915_vma.h
> b/drivers/gpu/drm/i915/i915_vma.h index dcb49f79ff7e..6c1369a40e03
> 100644
> --- a/drivers/gpu/drm/i915/i915_vma.h
> +++ b/drivers/gpu/drm/i915/i915_vma.h
> @@ -47,12 +47,6 @@ i915_vma_instance(struct drm_i915_gem_object *obj,
> 
>  void i915_vma_unpin_and_release(struct i915_vma **p_vma, unsigned int
> flags);  #define I915_VMA_RELEASE_MAP BIT(0)
> -
> -static inline bool i915_vma_is_active(const struct i915_vma *vma) -{
> -	return !i915_active_is_idle(&vma->active);
> -}
> -
>  /* do not reserve memory to prevent deadlocks */  #define
> __EXEC_OBJECT_NO_RESERVE BIT(31)
> 
> @@ -138,6 +132,48 @@ static inline u32 i915_ggtt_pin_bias(struct i915_vma
> *vma)
>  	return i915_vm_to_ggtt(vma->vm)->pin_bias;
>  }
> 
> +static inline bool i915_vma_is_persistent(const struct i915_vma *vma) {
> +	return test_bit(I915_VMA_PERSISTENT_BIT,
> __i915_vma_flags(vma)); }
> +
> +static inline void i915_vma_set_persistent(struct i915_vma *vma) {
> +	set_bit(I915_VMA_PERSISTENT_BIT, __i915_vma_flags(vma)); }
> +
> +static inline bool i915_vma_is_purged(const struct i915_vma *vma) {
> +	return test_bit(I915_VMA_PURGED_BIT, __i915_vma_flags(vma)); }
> +
> +static inline void i915_vma_set_purged(struct i915_vma *vma) {
> +	set_bit(I915_VMA_PURGED_BIT, __i915_vma_flags(vma)); }
> +
> +static inline bool i915_vma_is_freed(const struct i915_vma *vma) {
> +	return test_bit(I915_VMA_FREED_BIT, __i915_vma_flags(vma)); }
> +
> +static inline void i915_vma_set_freed(struct i915_vma *vma) {
> +	set_bit(I915_VMA_FREED_BIT, __i915_vma_flags(vma)); }
> +
> +static inline bool i915_vma_is_active(const struct i915_vma *vma) {
> +	if (i915_vma_is_persistent(vma)) {
> +		if (i915_vma_is_purged(vma))
> +			return false;
> +
> +		return i915_vm_is_active(vma->vm);
> +	}
> +
> +	return !i915_active_is_idle(&vma->active);
> +}
> +
>  static inline struct i915_vma *i915_vma_get(struct i915_vma *vma)  {
>  	i915_gem_object_get(vma->obj);
> @@ -408,8 +444,36 @@ int i915_vma_wait_for_bind(struct i915_vma *vma);
> 
>  static inline int i915_vma_sync(struct i915_vma *vma)  {
> +	int ret;
> +
>  	/* Wait for the asynchronous bindings and pending GPU reads */
> -	return i915_active_wait(&vma->active);
> +	ret = i915_active_wait(&vma->active);
> +	if (ret || !i915_vma_is_persistent(vma) ||
> i915_vma_is_purged(vma))
> +		return ret;
> +
> +	return i915_vm_sync(vma->vm);
> +}
> +
> +static inline bool i915_vma_is_bind_complete(struct i915_vma *vma) {
> +	/* Ensure vma bind is initiated */
> +	if (!i915_vma_is_bound(vma, I915_VMA_BIND_MASK))
> +		return false;
> +
> +	/* Ensure any binding started is complete */
> +	if (rcu_access_pointer(vma->active.excl.fence)) {
> +		struct dma_fence *fence;
> +
> +		rcu_read_lock();
> +		fence = dma_fence_get_rcu_safe(&vma->active.excl.fence);
> +		rcu_read_unlock();
> +		if (fence) {
> +			dma_fence_put(fence);
> +			return false;
> +		}
> +	}
> +
> +	return true;
>  }
> 
>  /**
> diff --git a/drivers/gpu/drm/i915/i915_vma_types.h
> b/drivers/gpu/drm/i915/i915_vma_types.h
> index 7d830a6a0b51..405c82e1bc30 100644
> --- a/drivers/gpu/drm/i915/i915_vma_types.h
> +++ b/drivers/gpu/drm/i915/i915_vma_types.h
> @@ -264,6 +264,28 @@ struct i915_vma {
>  #define I915_VMA_SCANOUT_BIT	17
>  #define I915_VMA_SCANOUT	((int)BIT(I915_VMA_SCANOUT_BIT))
> 
> +  /**
> +   * I915_VMA_PERSISTENT_BIT:
> +   * The vma is persistent (created with VM_BIND call).
> +   *
> +   * I915_VMA_PURGED_BIT:
> +   * The persistent vma is force unbound either due to VM_UNBIND call
> +   * from UMD or VM is released. Do not check/wait for VM activeness
> +   * in i915_vma_is_active() and i915_vma_sync() calls.
> +   *
> +   * I915_VMA_FREED_BIT:
> +   * The persistent vma is being released by UMD via VM_UNBIND call.
> +   * While releasing the vma, do not take VM_BIND lock as VM_UNBIND call
> +   * already holds the lock.
> +   */
> +#define I915_VMA_PERSISTENT_BIT	19
> +#define I915_VMA_PURGED_BIT	20
> +#define I915_VMA_FREED_BIT	21
> +
> +#define I915_VMA_PERSISTENT
> 	((int)BIT(I915_VMA_PERSISTENT_BIT))
> +#define I915_VMA_PURGED		((int)BIT(I915_VMA_PURGED_BIT))
> +#define I915_VMA_FREED		((int)BIT(I915_VMA_FREED_BIT))
> +
>  	struct i915_active active;
> 
>  #define I915_VMA_PAGES_BIAS 24
> @@ -292,6 +314,7 @@ struct i915_vma {
>  	struct list_head vm_bind_link; /* Link in persistent VMA list */
>  	/* Link in non-private persistent VMA list */
>  	struct list_head non_priv_vm_bind_link;
> +	struct list_head vm_rebind_link; /* Link in vm_rebind_list */
> 
>  	/** Timeline fence for vm_bind completion notification */
>  	struct {
> --
> 2.21.0.rc0.32.g243a4c7e27



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