[Intel-gfx] [PATCH 07/26] Revert "drm/i915/gem: Split eb_vma into its own allocation"
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Mon Jun 29 15:08:42 UTC 2020
On 23/06/2020 15:28, Maarten Lankhorst wrote:
> This reverts commit 0f1dd02295f35dcdcbaafcbcbbec0753884ab974.
> This conflicts with the ww mutex handling, which needs to drop
> the references after gpu submission anyway, because otherwise we
> may risk unlocking a BO after first freeing it.
What is the problem here? eb_vma_array_put in eb_move_to_gpu? If so,
could you just move this put to later in the sequence? I am simply
thinking how to avoid controversial reverts. Because on the other hand I
did not figure out what 0f1dd02295f35dcdcbaafcbcbbec0753884ab974 fixed
in a few minutes I spent staring at the patch.
Regards,
Tvrtko
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> ---
> .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 124 +++++++-----------
> 1 file changed, 51 insertions(+), 73 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index 7cb44915cfc7..2636a130fb57 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -40,11 +40,6 @@ struct eb_vma {
> u32 handle;
> };
>
> -struct eb_vma_array {
> - struct kref kref;
> - struct eb_vma vma[];
> -};
> -
> enum {
> FORCE_CPU_RELOC = 1,
> FORCE_GTT_RELOC,
> @@ -57,6 +52,7 @@ enum {
> #define __EXEC_OBJECT_NEEDS_MAP BIT(29)
> #define __EXEC_OBJECT_NEEDS_BIAS BIT(28)
> #define __EXEC_OBJECT_INTERNAL_FLAGS (~0u << 28) /* all of the above */
> +#define __EXEC_OBJECT_RESERVED (__EXEC_OBJECT_HAS_PIN | __EXEC_OBJECT_HAS_FENCE)
>
> #define __EXEC_HAS_RELOC BIT(31)
> #define __EXEC_INTERNAL_FLAGS (~0u << 31)
> @@ -287,7 +283,6 @@ struct i915_execbuffer {
> */
> int lut_size;
> struct hlist_head *buckets; /** ht for relocation handles */
> - struct eb_vma_array *array;
> };
>
> static int eb_parse(struct i915_execbuffer *eb);
> @@ -299,62 +294,8 @@ static inline bool eb_use_cmdparser(const struct i915_execbuffer *eb)
> eb->args->batch_len);
> }
>
> -static struct eb_vma_array *eb_vma_array_create(unsigned int count)
> -{
> - struct eb_vma_array *arr;
> -
> - arr = kvmalloc(struct_size(arr, vma, count), GFP_KERNEL | __GFP_NOWARN);
> - if (!arr)
> - return NULL;
> -
> - kref_init(&arr->kref);
> - arr->vma[0].vma = NULL;
> -
> - return arr;
> -}
> -
> -static inline void eb_unreserve_vma(struct eb_vma *ev)
> -{
> - struct i915_vma *vma = ev->vma;
> -
> - if (unlikely(ev->flags & __EXEC_OBJECT_HAS_FENCE))
> - __i915_vma_unpin_fence(vma);
> -
> - if (ev->flags & __EXEC_OBJECT_HAS_PIN)
> - __i915_vma_unpin(vma);
> -
> - ev->flags &= ~(__EXEC_OBJECT_HAS_PIN |
> - __EXEC_OBJECT_HAS_FENCE);
> -}
> -
> -static void eb_vma_array_destroy(struct kref *kref)
> -{
> - struct eb_vma_array *arr = container_of(kref, typeof(*arr), kref);
> - struct eb_vma *ev = arr->vma;
> -
> - while (ev->vma) {
> - eb_unreserve_vma(ev);
> - i915_vma_put(ev->vma);
> - ev++;
> - }
> -
> - kvfree(arr);
> -}
> -
> -static void eb_vma_array_put(struct eb_vma_array *arr)
> -{
> - kref_put(&arr->kref, eb_vma_array_destroy);
> -}
> -
> static int eb_create(struct i915_execbuffer *eb)
> {
> - /* Allocate an extra slot for use by the command parser + sentinel */
> - eb->array = eb_vma_array_create(eb->buffer_count + 2);
> - if (!eb->array)
> - return -ENOMEM;
> -
> - eb->vma = eb->array->vma;
> -
> if (!(eb->args->flags & I915_EXEC_HANDLE_LUT)) {
> unsigned int size = 1 + ilog2(eb->buffer_count);
>
> @@ -388,10 +329,8 @@ static int eb_create(struct i915_execbuffer *eb)
> break;
> } while (--size);
>
> - if (unlikely(!size)) {
> - eb_vma_array_put(eb->array);
> + if (unlikely(!size))
> return -ENOMEM;
> - }
>
> eb->lut_size = size;
> } else {
> @@ -502,6 +441,26 @@ eb_pin_vma(struct i915_execbuffer *eb,
> return !eb_vma_misplaced(entry, vma, ev->flags);
> }
>
> +static inline void __eb_unreserve_vma(struct i915_vma *vma, unsigned int flags)
> +{
> + GEM_BUG_ON(!(flags & __EXEC_OBJECT_HAS_PIN));
> +
> + if (unlikely(flags & __EXEC_OBJECT_HAS_FENCE))
> + __i915_vma_unpin_fence(vma);
> +
> + __i915_vma_unpin(vma);
> +}
> +
> +static inline void
> +eb_unreserve_vma(struct eb_vma *ev)
> +{
> + if (!(ev->flags & __EXEC_OBJECT_HAS_PIN))
> + return;
> +
> + __eb_unreserve_vma(ev->vma, ev->flags);
> + ev->flags &= ~__EXEC_OBJECT_RESERVED;
> +}
> +
> static int
> eb_validate_vma(struct i915_execbuffer *eb,
> struct drm_i915_gem_exec_object2 *entry,
> @@ -944,13 +903,31 @@ eb_get_vma(const struct i915_execbuffer *eb, unsigned long handle)
> }
> }
>
> +static void eb_release_vmas(const struct i915_execbuffer *eb)
> +{
> + const unsigned int count = eb->buffer_count;
> + unsigned int i;
> +
> + for (i = 0; i < count; i++) {
> + struct eb_vma *ev = &eb->vma[i];
> + struct i915_vma *vma = ev->vma;
> +
> + if (!vma)
> + break;
> +
> + eb->vma[i].vma = NULL;
> +
> + if (ev->flags & __EXEC_OBJECT_HAS_PIN)
> + __eb_unreserve_vma(vma, ev->flags);
> +
> + i915_vma_put(vma);
> + }
> +}
> +
> static void eb_destroy(const struct i915_execbuffer *eb)
> {
> GEM_BUG_ON(eb->reloc_cache.rq);
>
> - if (eb->array)
> - eb_vma_array_put(eb->array);
> -
> if (eb->lut_size > 0)
> kfree(eb->buckets);
> }
> @@ -2039,12 +2016,9 @@ static int eb_move_to_gpu(struct i915_execbuffer *eb)
> err = i915_vma_move_to_active(vma, eb->request, flags);
>
> i915_vma_unlock(vma);
> - eb_unreserve_vma(ev);
> }
> ww_acquire_fini(&acquire);
>
> - eb_vma_array_put(fetch_and_zero(&eb->array));
> -
> if (unlikely(err))
> goto err_skip;
>
> @@ -2340,7 +2314,6 @@ static int eb_parse(struct i915_execbuffer *eb)
> eb->vma[eb->buffer_count].vma = i915_vma_get(shadow);
> eb->vma[eb->buffer_count].flags = __EXEC_OBJECT_HAS_PIN;
> eb->batch = &eb->vma[eb->buffer_count++];
> - eb->vma[eb->buffer_count].vma = NULL;
>
> eb->trampoline = trampoline;
> eb->batch_start_offset = 0;
> @@ -2838,6 +2811,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
> args->flags |= __EXEC_HAS_RELOC;
>
> eb.exec = exec;
> + eb.vma = (struct eb_vma *)(exec + args->buffer_count + 1);
> + eb.vma[0].vma = NULL;
>
> eb.invalid_flags = __EXEC_OBJECT_UNKNOWN_FLAGS;
> reloc_cache_init(&eb.reloc_cache, eb.i915);
> @@ -3014,6 +2989,8 @@ i915_gem_do_execbuffer(struct drm_device *dev,
> if (batch->private)
> intel_gt_buffer_pool_put(batch->private);
> err_vma:
> + if (eb.exec)
> + eb_release_vmas(&eb);
> if (eb.trampoline)
> i915_vma_unpin(eb.trampoline);
> eb_unpin_engine(&eb);
> @@ -3031,7 +3008,7 @@ i915_gem_do_execbuffer(struct drm_device *dev,
>
> static size_t eb_element_size(void)
> {
> - return sizeof(struct drm_i915_gem_exec_object2);
> + return sizeof(struct drm_i915_gem_exec_object2) + sizeof(struct eb_vma);
> }
>
> static bool check_buffer_count(size_t count)
> @@ -3087,7 +3064,7 @@ i915_gem_execbuffer_ioctl(struct drm_device *dev, void *data,
> /* Copy in the exec list from userland */
> exec_list = kvmalloc_array(count, sizeof(*exec_list),
> __GFP_NOWARN | GFP_KERNEL);
> - exec2_list = kvmalloc_array(count, eb_element_size(),
> + exec2_list = kvmalloc_array(count + 1, eb_element_size(),
> __GFP_NOWARN | GFP_KERNEL);
> if (exec_list == NULL || exec2_list == NULL) {
> drm_dbg(&i915->drm,
> @@ -3165,7 +3142,8 @@ i915_gem_execbuffer2_ioctl(struct drm_device *dev, void *data,
> if (err)
> return err;
>
> - exec2_list = kvmalloc_array(count, eb_element_size(),
> + /* Allocate an extra slot for use by the command parser */
> + exec2_list = kvmalloc_array(count + 1, eb_element_size(),
> __GFP_NOWARN | GFP_KERNEL);
> if (exec2_list == NULL) {
> drm_dbg(&i915->drm, "Failed to allocate exec list for %zd buffers\n",
>
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