Quoting Eric Anholt (2017-06-22 21:50:54)
> This has proven immensely useful for debugging memory leaks and
> overallocation (which is a rather serious concern on the platform,
> given that we typically run at about 256MB of CMA out of up to 1GB
> total memory, with framebuffers that are about 8MB ecah).
>
> The state of the art without this is to dump debug logs from every GL
> application, guess as to kernel allocations based on bo_stats, and try
> to merge that all together into a global picture of memory allocation
> state. With this, you can add a couple of calls to the debug build of
> the 3D driver and get a pretty detailed view of GPU memory usage from
> /debug/dri/0/bo_stats (or when we debug print to dmesg on allocation
> failure).
>
> The Mesa side currently labels at the gallium resource level (so you
> see that a 1920x20 pixmap has been created, presumably for the window
> system panel), but we could extend that to be even more useful with
> glObjectLabel() names being sent all the way down to the kernel.
>
> (partial) example of sorted debugfs output with Mesa labeling all
> resources:
>
> kernel BO cache: 16392kb BOs (3)
> tiling shadow 1920x1080: 8160kb BOs (1)
> resource 1920x1080@32/0: 8160kb BOs (1)
> scanout resource 1920x1080@32/0: 8100kb BOs (1)
> kernel: 8100kb BOs (1)
>
> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
> ---
> static void vc4_bo_stats_dump(struct vc4_dev *vc4)
> {
Now unused?
> - DRM_INFO("num bos allocated: %d\n",
> - vc4->bo_stats.num_allocated);
> - DRM_INFO("size bos allocated: %dkb\n",
> - vc4->bo_stats.size_allocated / 1024);
> - DRM_INFO("num bos used: %d\n",
> - vc4->bo_stats.num_allocated - vc4->bo_stats.num_cached);
> - DRM_INFO("size bos used: %dkb\n",
> - (vc4->bo_stats.size_allocated -
> - vc4->bo_stats.size_cached) / 1024);
> - DRM_INFO("num bos cached: %d\n",
> - vc4->bo_stats.num_cached);
> - DRM_INFO("size bos cached: %dkb\n",
> - vc4->bo_stats.size_cached / 1024);
> + int i;
> +
> + for (i = 0; i < vc4->num_labels; i++) {
> + if (!vc4->bo_labels[i].num_allocated)
> + continue;
> +
> + DRM_INFO("%30s: %6dkb BOs (%d)\n",
> + vc4->bo_labels[i].name,
> + vc4->bo_labels[i].size_allocated / 1024,
> + vc4->bo_labels[i].num_allocated);
> + }
> }
>
> #ifdef CONFIG_DEBUG_FS
> +/* Must be called with bo_lock held. */
> +static void vc4_bo_set_label(struct drm_gem_object *gem_obj, int label)
> +{
> + struct vc4_bo *bo = to_vc4_bo(gem_obj);
> + struct vc4_dev *vc4 = to_vc4_dev(gem_obj->dev);
lockdep_assert_held(&vc4->bo_lock);
> +
> + vc4->bo_labels[label].num_allocated++;
> + vc4->bo_labels[label].size_allocated += gem_obj->size;
This gets called with label=-1 on destroy.
> + vc4->bo_labels[bo->label].num_allocated--;
> + vc4->bo_labels[bo->label].size_allocated -= gem_obj->size;
Ok, preassigned to TYPE_KERNEL on creation.
> + if (vc4->bo_labels[bo->label].num_allocated == 0 &&
> + is_user_label(bo->label)) {
> + /* Free user BO label slots on last unreference. */
> + kfree(vc4->bo_labels[bo->label].name);
> + vc4->bo_labels[bo->label].name = NULL;
> + }
This seems dubious. As a user I would expect the label I created to last
until I closed the fd. Otherwise if I ever close all bo of one type,
wait a few seconds for the cache to be reaped, then reallocate a new bo,
someone else may have assigned my label a new name.
If that's guarded against, a comment would help.
> +
> + bo->label = label;
> +}
> +int vc4_label_bo_ioctl(struct drm_device *dev, void *data,
> + struct drm_file *file_priv)
> +{
> + struct vc4_dev *vc4 = to_vc4_dev(dev);
> + struct drm_vc4_label_bo *args = data;
> + char *name;
> + struct drm_gem_object *gem_obj;
> + int ret = 0, label;
> +
> + name = kmalloc(args->len + 1, GFP_KERNEL);
> + if (!name)
> + return -ENOMEM;
> +
> + if (copy_from_user(name, (void __user *)(uintptr_t)args->name,
> + args->len)) {
> + kfree(name);
> + return -EFAULT;
> + }
> + name[args->len] = 0;
if (!args->len)
return -EINVAL;
name = strndup_user(u64_to_user_ptr(args->name), args->len + 1);
if (IS_ERR(name))
return PTR_ERR(name);
-Chris
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