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Date: Wed, 25 Mar 2009 22:52:17 +0000 (GMT)
From: Dave Airlie <airlied@...ux.ie>
To: Eric Anholt <eric@...olt.net>
cc: linux-kernel@...r.kernel.org, dri-devel@...ts.sourceforge.net
Subject: Re: [PATCH 2/6] drm/i915: Make GEM object's page lists refcounted
instead of get/free.
> We've wanted this for a few consumers that touch the pages directly (such as
> the following commit), which have been doing the refcounting outside of
> get/put pages.
No idea if this is a valid point or not but whenever I see refcount that
isn't a kref my internal, "should this be a kref" o-meter goes off.
Dave.
> ---
> drivers/gpu/drm/i915/i915_drv.h | 3 +-
> drivers/gpu/drm/i915/i915_gem.c | 70 ++++++++++++++++++++-------------------
> 2 files changed, 38 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index d6cc986..75e3384 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -404,7 +404,8 @@ struct drm_i915_gem_object {
> /** AGP memory structure for our GTT binding. */
> DRM_AGP_MEM *agp_mem;
>
> - struct page **page_list;
> + struct page **pages;
> + int pages_refcount;
>
> /**
> * Current offset of the object in GTT space.
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 35f8c7b..b998d65 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -43,8 +43,8 @@ static int i915_gem_object_set_cpu_read_domain_range(struct drm_gem_object *obj,
> uint64_t offset,
> uint64_t size);
> static void i915_gem_object_set_to_full_cpu_read_domain(struct drm_gem_object *obj);
> -static int i915_gem_object_get_page_list(struct drm_gem_object *obj);
> -static void i915_gem_object_free_page_list(struct drm_gem_object *obj);
> +static int i915_gem_object_get_pages(struct drm_gem_object *obj);
> +static void i915_gem_object_put_pages(struct drm_gem_object *obj);
> static int i915_gem_object_wait_rendering(struct drm_gem_object *obj);
> static int i915_gem_object_bind_to_gtt(struct drm_gem_object *obj,
> unsigned alignment);
> @@ -928,29 +928,30 @@ i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void *data,
> }
>
> static void
> -i915_gem_object_free_page_list(struct drm_gem_object *obj)
> +i915_gem_object_put_pages(struct drm_gem_object *obj)
> {
> struct drm_i915_gem_object *obj_priv = obj->driver_private;
> int page_count = obj->size / PAGE_SIZE;
> int i;
>
> - if (obj_priv->page_list == NULL)
> - return;
> + BUG_ON(obj_priv->pages_refcount == 0);
>
> + if (--obj_priv->pages_refcount != 0)
> + return;
>
> for (i = 0; i < page_count; i++)
> - if (obj_priv->page_list[i] != NULL) {
> + if (obj_priv->pages[i] != NULL) {
> if (obj_priv->dirty)
> - set_page_dirty(obj_priv->page_list[i]);
> - mark_page_accessed(obj_priv->page_list[i]);
> - page_cache_release(obj_priv->page_list[i]);
> + set_page_dirty(obj_priv->pages[i]);
> + mark_page_accessed(obj_priv->pages[i]);
> + page_cache_release(obj_priv->pages[i]);
> }
> obj_priv->dirty = 0;
>
> - drm_free(obj_priv->page_list,
> + drm_free(obj_priv->pages,
> page_count * sizeof(struct page *),
> DRM_MEM_DRIVER);
> - obj_priv->page_list = NULL;
> + obj_priv->pages = NULL;
> }
>
> static void
> @@ -1402,7 +1403,7 @@ i915_gem_object_unbind(struct drm_gem_object *obj)
> if (obj_priv->fence_reg != I915_FENCE_REG_NONE)
> i915_gem_clear_fence_reg(obj);
>
> - i915_gem_object_free_page_list(obj);
> + i915_gem_object_put_pages(obj);
>
> if (obj_priv->gtt_space) {
> atomic_dec(&dev->gtt_count);
> @@ -1521,7 +1522,7 @@ i915_gem_evict_everything(struct drm_device *dev)
> }
>
> static int
> -i915_gem_object_get_page_list(struct drm_gem_object *obj)
> +i915_gem_object_get_pages(struct drm_gem_object *obj)
> {
> struct drm_i915_gem_object *obj_priv = obj->driver_private;
> int page_count, i;
> @@ -1530,18 +1531,19 @@ i915_gem_object_get_page_list(struct drm_gem_object *obj)
> struct page *page;
> int ret;
>
> - if (obj_priv->page_list)
> + if (obj_priv->pages_refcount++ != 0)
> return 0;
>
> /* Get the list of pages out of our struct file. They'll be pinned
> * at this point until we release them.
> */
> page_count = obj->size / PAGE_SIZE;
> - BUG_ON(obj_priv->page_list != NULL);
> - obj_priv->page_list = drm_calloc(page_count, sizeof(struct page *),
> - DRM_MEM_DRIVER);
> - if (obj_priv->page_list == NULL) {
> + BUG_ON(obj_priv->pages != NULL);
> + obj_priv->pages = drm_calloc(page_count, sizeof(struct page *),
> + DRM_MEM_DRIVER);
> + if (obj_priv->pages == NULL) {
> DRM_ERROR("Faled to allocate page list\n");
> + obj_priv->pages_refcount--;
> return -ENOMEM;
> }
>
> @@ -1552,10 +1554,10 @@ i915_gem_object_get_page_list(struct drm_gem_object *obj)
> if (IS_ERR(page)) {
> ret = PTR_ERR(page);
> DRM_ERROR("read_mapping_page failed: %d\n", ret);
> - i915_gem_object_free_page_list(obj);
> + i915_gem_object_put_pages(obj);
> return ret;
> }
> - obj_priv->page_list[i] = page;
> + obj_priv->pages[i] = page;
> }
> return 0;
> }
> @@ -1878,7 +1880,7 @@ i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment)
> DRM_INFO("Binding object of size %d at 0x%08x\n",
> obj->size, obj_priv->gtt_offset);
> #endif
> - ret = i915_gem_object_get_page_list(obj);
> + ret = i915_gem_object_get_pages(obj);
> if (ret) {
> drm_mm_put_block(obj_priv->gtt_space);
> obj_priv->gtt_space = NULL;
> @@ -1890,12 +1892,12 @@ i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment)
> * into the GTT.
> */
> obj_priv->agp_mem = drm_agp_bind_pages(dev,
> - obj_priv->page_list,
> + obj_priv->pages,
> page_count,
> obj_priv->gtt_offset,
> obj_priv->agp_type);
> if (obj_priv->agp_mem == NULL) {
> - i915_gem_object_free_page_list(obj);
> + i915_gem_object_put_pages(obj);
> drm_mm_put_block(obj_priv->gtt_space);
> obj_priv->gtt_space = NULL;
> return -ENOMEM;
> @@ -1922,10 +1924,10 @@ i915_gem_clflush_object(struct drm_gem_object *obj)
> * to GPU, and we can ignore the cache flush because it'll happen
> * again at bind time.
> */
> - if (obj_priv->page_list == NULL)
> + if (obj_priv->pages == NULL)
> return;
>
> - drm_clflush_pages(obj_priv->page_list, obj->size / PAGE_SIZE);
> + drm_clflush_pages(obj_priv->pages, obj->size / PAGE_SIZE);
> }
>
> /** Flushes any GPU write domain for the object if it's dirty. */
> @@ -2270,7 +2272,7 @@ i915_gem_object_set_to_full_cpu_read_domain(struct drm_gem_object *obj)
> for (i = 0; i <= (obj->size - 1) / PAGE_SIZE; i++) {
> if (obj_priv->page_cpu_valid[i])
> continue;
> - drm_clflush_pages(obj_priv->page_list + i, 1);
> + drm_clflush_pages(obj_priv->pages + i, 1);
> }
> drm_agp_chipset_flush(dev);
> }
> @@ -2336,7 +2338,7 @@ i915_gem_object_set_cpu_read_domain_range(struct drm_gem_object *obj,
> if (obj_priv->page_cpu_valid[i])
> continue;
>
> - drm_clflush_pages(obj_priv->page_list + i, 1);
> + drm_clflush_pages(obj_priv->pages + i, 1);
>
> obj_priv->page_cpu_valid[i] = 1;
> }
> @@ -3304,7 +3306,7 @@ i915_gem_init_hws(struct drm_device *dev)
>
> dev_priv->status_gfx_addr = obj_priv->gtt_offset;
>
> - dev_priv->hw_status_page = kmap(obj_priv->page_list[0]);
> + dev_priv->hw_status_page = kmap(obj_priv->pages[0]);
> if (dev_priv->hw_status_page == NULL) {
> DRM_ERROR("Failed to map status page.\n");
> memset(&dev_priv->hws_map, 0, sizeof(dev_priv->hws_map));
> @@ -3334,7 +3336,7 @@ i915_gem_cleanup_hws(struct drm_device *dev)
> obj = dev_priv->hws_obj;
> obj_priv = obj->driver_private;
>
> - kunmap(obj_priv->page_list[0]);
> + kunmap(obj_priv->pages[0]);
> i915_gem_object_unpin(obj);
> drm_gem_object_unreference(obj);
> dev_priv->hws_obj = NULL;
> @@ -3637,20 +3639,20 @@ void i915_gem_detach_phys_object(struct drm_device *dev,
> if (!obj_priv->phys_obj)
> return;
>
> - ret = i915_gem_object_get_page_list(obj);
> + ret = i915_gem_object_get_pages(obj);
> if (ret)
> goto out;
>
> page_count = obj->size / PAGE_SIZE;
>
> for (i = 0; i < page_count; i++) {
> - char *dst = kmap_atomic(obj_priv->page_list[i], KM_USER0);
> + char *dst = kmap_atomic(obj_priv->pages[i], KM_USER0);
> char *src = obj_priv->phys_obj->handle->vaddr + (i * PAGE_SIZE);
>
> memcpy(dst, src, PAGE_SIZE);
> kunmap_atomic(dst, KM_USER0);
> }
> - drm_clflush_pages(obj_priv->page_list, page_count);
> + drm_clflush_pages(obj_priv->pages, page_count);
> drm_agp_chipset_flush(dev);
> out:
> obj_priv->phys_obj->cur_obj = NULL;
> @@ -3693,7 +3695,7 @@ i915_gem_attach_phys_object(struct drm_device *dev,
> obj_priv->phys_obj = dev_priv->mm.phys_objs[id - 1];
> obj_priv->phys_obj->cur_obj = obj;
>
> - ret = i915_gem_object_get_page_list(obj);
> + ret = i915_gem_object_get_pages(obj);
> if (ret) {
> DRM_ERROR("failed to get page list\n");
> goto out;
> @@ -3702,7 +3704,7 @@ i915_gem_attach_phys_object(struct drm_device *dev,
> page_count = obj->size / PAGE_SIZE;
>
> for (i = 0; i < page_count; i++) {
> - char *src = kmap_atomic(obj_priv->page_list[i], KM_USER0);
> + char *src = kmap_atomic(obj_priv->pages[i], KM_USER0);
> char *dst = obj_priv->phys_obj->handle->vaddr + (i * PAGE_SIZE);
>
> memcpy(dst, src, PAGE_SIZE);
>
--
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