Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes:
> 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.
>
> Fixes: 003d8b9143a6 ("drm/i915/gem: Only call eb_lookup_vma once during execbuf ioctl")
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
from other thread,
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
> ---
> .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 51 ++++++++-----------
> drivers/gpu/drm/i915/i915_drv.h | 6 ---
> 2 files changed, 20 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index 7bb27f382af7..faa5b5c99a9a 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -610,7 +610,7 @@ 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.
> @@ -626,8 +626,10 @@ 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);
> @@ -635,7 +637,7 @@ 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);
> @@ -666,7 +668,9 @@ 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;
> }
>
> @@ -680,15 +684,20 @@ 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)
> @@ -1631,7 +1640,6 @@ 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;
> @@ -1642,8 +1650,6 @@ static noinline int eb_relocate_slow(struct i915_execbuffer *eb)
> goto out;
> }
>
> - mutex_unlock(&dev->struct_mutex);
> -
> /*
> * We take 3 passes through the slowpatch.
> *
> @@ -1666,21 +1672,8 @@ static noinline int eb_relocate_slow(struct i915_execbuffer *eb)
> 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) {
> @@ -1738,9 +1731,11 @@ static int eb_relocate(struct i915_execbuffer *eb)
> if (err)
> return err;
>
> - err = eb_reserve(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) {
> @@ -2690,10 +2685,6 @@ 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) {
> /*
> @@ -2837,8 +2828,6 @@ i915_gem_do_execbuffer(struct drm_device *dev,
> 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);
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 123d0fadfafc..c081f4ec87df 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -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);
> --
> 2.25.1
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