>-----Original Message-----
>From: Intel-gfx <intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Chris
>Wilson
>Sent: Monday, January 20, 2020 5:49 AM
>To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
>Cc: Auld, Matthew <matthew.auld@xxxxxxxxx>
>Subject: [PATCH 4/5] drm/i915/gem: Convert vm idr to xarray
>
>Replace the vm_idr + vm_idr_mutex to an XArray. The XArray data
>structure is now used to implement IDRs, and provides its won locking.
s/won/own
>We can simply remove the IDR wrapper and in the process also remove our
>extra mutex.
>
>Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
>---
> drivers/gpu/drm/i915/gem/i915_gem_context.c | 80 ++++++---------------
> drivers/gpu/drm/i915/i915_drv.h | 4 +-
> 2 files changed, 22 insertions(+), 62 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>index a2e57e62af30..d2e4e8cbf4d4 100644
>--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>@@ -761,12 +761,6 @@ void i915_gem_driver_release__contexts(struct
>drm_i915_private *i915)
> flush_work(&i915->gem.contexts.free_work);
> }
>
>-static int vm_idr_cleanup(int id, void *p, void *data)
>-{
>- i915_vm_put(p);
>- return 0;
>-}
>-
> static int gem_context_register(struct i915_gem_context *ctx,
> struct drm_i915_file_private *fpriv,
> u32 *id)
>@@ -803,9 +797,7 @@ int i915_gem_context_open(struct drm_i915_private
>*i915,
> u32 id;
>
> xa_init_flags(&file_priv->context_xa, XA_FLAGS_ALLOC);
>-
>- mutex_init(&file_priv->vm_idr_lock);
>- idr_init_base(&file_priv->vm_idr, 1);
>+ xa_init_flags(&file_priv->vm_xa, XA_FLAGS_ALLOC1);
>
> ctx = i915_gem_create_context(i915, 0);
> if (IS_ERR(ctx)) {
>@@ -823,9 +815,8 @@ int i915_gem_context_open(struct drm_i915_private
>*i915,
> err_ctx:
> context_close(ctx);
> err:
>- idr_destroy(&file_priv->vm_idr);
>+ xa_destroy(&file_priv->vm_xa);
> xa_destroy(&file_priv->context_xa);
>- mutex_destroy(&file_priv->vm_idr_lock);
> return err;
> }
>
>@@ -833,6 +824,7 @@ void i915_gem_context_close(struct drm_file *file)
> {
> struct drm_i915_file_private *file_priv = file->driver_priv;
> struct drm_i915_private *i915 = file_priv->dev_priv;
>+ struct i915_address_space *vm;
> struct i915_gem_context *ctx;
> unsigned long idx;
>
>@@ -840,9 +832,9 @@ void i915_gem_context_close(struct drm_file *file)
> context_close(ctx);
> xa_destroy(&file_priv->context_xa);
>
>- idr_for_each(&file_priv->vm_idr, vm_idr_cleanup, NULL);
>- idr_destroy(&file_priv->vm_idr);
>- mutex_destroy(&file_priv->vm_idr_lock);
>+ xa_for_each(&file_priv->vm_xa, idx, vm)
>+ i915_vm_put(vm);
>+ xa_destroy(&file_priv->vm_xa);
>
> contexts_flush_free(&i915->gem.contexts);
> }
>@@ -876,23 +868,13 @@ int i915_gem_vm_create_ioctl(struct drm_device
>*dev, void *data,
> goto err_put;
> }
>
>- err = mutex_lock_interruptible(&file_priv->vm_idr_lock);
>+ err = xa_alloc(&file_priv->vm_xa, &args->vm_id,
>+ &ppgtt->vm, xa_limit_32b, GFP_KERNEL);
> if (err)
> goto err_put;
>
>- err = idr_alloc(&file_priv->vm_idr, &ppgtt->vm, 0, 0, GFP_KERNEL);
>- if (err < 0)
>- goto err_unlock;
>-
>- GEM_BUG_ON(err == 0); /* reserved for invalid/unassigned ppgtt */
Moving this comment to the xa_init_flags() would help me understand
why the index started at 1.
>- mutex_unlock(&file_priv->vm_idr_lock);
>-
>- args->vm_id = err;
> return 0;
>
>-err_unlock:
>- mutex_unlock(&file_priv->vm_idr_lock);
> err_put:
> i915_vm_put(&ppgtt->vm);
> return err;
>@@ -904,8 +886,6 @@ int i915_gem_vm_destroy_ioctl(struct drm_device
>*dev, void *data,
> struct drm_i915_file_private *file_priv = file->driver_priv;
> struct drm_i915_gem_vm_control *args = data;
> struct i915_address_space *vm;
>- int err;
>- u32 id;
>
> if (args->flags)
> return -EINVAL;
>@@ -913,17 +893,7 @@ int i915_gem_vm_destroy_ioctl(struct drm_device
>*dev, void *data,
> if (args->extensions)
> return -EINVAL;
>
>- id = args->vm_id;
>- if (!id)
>- return -ENOENT;
>-
>- err = mutex_lock_interruptible(&file_priv->vm_idr_lock);
>- if (err)
>- return err;
>-
>- vm = idr_remove(&file_priv->vm_idr, id);
>-
>- mutex_unlock(&file_priv->vm_idr_lock);
>+ vm = xa_erase(&file_priv->vm_xa, args->vm_id);
> if (!vm)
> return -ENOENT;
>
>@@ -1021,35 +991,27 @@ static int get_ppgtt(struct drm_i915_file_private
>*file_priv,
> struct drm_i915_gem_context_param *args)
> {
> struct i915_address_space *vm;
>- int ret;
>+ int err = -ENODEV;
>+ u32 id;
>
> if (!rcu_access_pointer(ctx->vm))
> return -ENODEV;
>
> rcu_read_lock();
> vm = context_get_vm_rcu(ctx);
>+ if (vm)
>+ err = xa_alloc(&file_priv->vm_xa, &id, vm,
>+ xa_limit_32b, GFP_KERNEL);
> rcu_read_unlock();
>+ if (!err) {
>+ i915_vm_open(vm);
Why did you switch to success path in the if here?
Can you do:
if (err)
goto err_put;
?
>- ret = mutex_lock_interruptible(&file_priv->vm_idr_lock);
>- if (ret)
>- goto err_put;
>-
>- ret = idr_alloc(&file_priv->vm_idr, vm, 0, 0, GFP_KERNEL);
>- GEM_BUG_ON(!ret);
>- if (ret < 0)
>- goto err_unlock;
>-
>- i915_vm_open(vm);
>-
>- args->size = 0;
>- args->value = ret;
>+ args->size = 0;
>+ args->value = id;
Would passing args->value to the xa_alloc be a useful?
Nice clean up.
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
Mike
>+ }
>
>- ret = 0;
>-err_unlock:
>- mutex_unlock(&file_priv->vm_idr_lock);
>-err_put:
> i915_vm_put(vm);
>- return ret;
>+ return err;
> }
>
> static void set_ppgtt_barrier(void *data)
>@@ -1151,7 +1113,7 @@ static int set_ppgtt(struct drm_i915_file_private
>*file_priv,
> return -ENOENT;
>
> rcu_read_lock();
>- vm = idr_find(&file_priv->vm_idr, args->value);
>+ vm = xa_load(&file_priv->vm_xa, args->value);
> if (vm && !kref_get_unless_zero(&vm->ref))
> vm = NULL;
> rcu_read_unlock();
>diff --git a/drivers/gpu/drm/i915/i915_drv.h
>b/drivers/gpu/drm/i915/i915_drv.h
>index 077af22b8340..50abf9113b2f 100644
>--- a/drivers/gpu/drm/i915/i915_drv.h
>+++ b/drivers/gpu/drm/i915/i915_drv.h
>@@ -203,9 +203,7 @@ struct drm_i915_file_private {
> } mm;
>
> struct xarray context_xa;
>-
>- struct idr vm_idr;
>- struct mutex vm_idr_lock; /* guards vm_idr */
>+ struct xarray vm_xa;
>
> unsigned int bsd_engine;
>
>--
>2.25.0
>
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