forked from mirrors/linux
drm/vc4: Add a BO cache.
We need to allocate new BOs in the kernel as part of each frame, but the CMA allocator is way too slow for that. As an optimization, keep track of recently-freed BOs and reuse them, with a 1 second timeout to fully free them back to the system. This improves 3D performance by about 15%. Signed-off-by: Eric Anholt <eric@anholt.net>
This commit is contained in:
Eric Anholt
parent
10028c5ab1
commit
c826a6e106
4 changed files with 384 additions and 8 deletions
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@ -12,19 +12,229 @@
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* access to system memory with no MMU in between. To support it, we
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* use the GEM CMA helper functions to allocate contiguous ranges of
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* physical memory for our BOs.
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*
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* Since the CMA allocator is very slow, we keep a cache of recently
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* freed BOs around so that the kernel's allocation of objects for 3D
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* rendering can return quickly.
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*/
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#include "vc4_drv.h"
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struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t size)
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static void vc4_bo_stats_dump(struct vc4_dev *vc4)
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{
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DRM_INFO("num bos allocated: %d\n",
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vc4->bo_stats.num_allocated);
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DRM_INFO("size bos allocated: %dkb\n",
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vc4->bo_stats.size_allocated / 1024);
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DRM_INFO("num bos used: %d\n",
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vc4->bo_stats.num_allocated - vc4->bo_stats.num_cached);
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DRM_INFO("size bos used: %dkb\n",
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(vc4->bo_stats.size_allocated -
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vc4->bo_stats.size_cached) / 1024);
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DRM_INFO("num bos cached: %d\n",
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vc4->bo_stats.num_cached);
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DRM_INFO("size bos cached: %dkb\n",
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vc4->bo_stats.size_cached / 1024);
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}
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#ifdef CONFIG_DEBUG_FS
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int vc4_bo_stats_debugfs(struct seq_file *m, void *unused)
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{
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struct drm_info_node *node = (struct drm_info_node *)m->private;
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struct drm_device *dev = node->minor->dev;
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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struct vc4_bo_stats stats;
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/* Take a snapshot of the current stats with the lock held. */
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mutex_lock(&vc4->bo_lock);
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stats = vc4->bo_stats;
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mutex_unlock(&vc4->bo_lock);
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seq_printf(m, "num bos allocated: %d\n",
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stats.num_allocated);
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seq_printf(m, "size bos allocated: %dkb\n",
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stats.size_allocated / 1024);
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seq_printf(m, "num bos used: %d\n",
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stats.num_allocated - stats.num_cached);
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seq_printf(m, "size bos used: %dkb\n",
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(stats.size_allocated - stats.size_cached) / 1024);
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seq_printf(m, "num bos cached: %d\n",
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stats.num_cached);
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seq_printf(m, "size bos cached: %dkb\n",
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stats.size_cached / 1024);
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return 0;
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}
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#endif
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static uint32_t bo_page_index(size_t size)
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{
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return (size / PAGE_SIZE) - 1;
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}
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/* Must be called with bo_lock held. */
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static void vc4_bo_destroy(struct vc4_bo *bo)
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{
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struct drm_gem_object *obj = &bo->base.base;
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struct vc4_dev *vc4 = to_vc4_dev(obj->dev);
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vc4->bo_stats.num_allocated--;
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vc4->bo_stats.size_allocated -= obj->size;
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drm_gem_cma_free_object(obj);
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}
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/* Must be called with bo_lock held. */
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static void vc4_bo_remove_from_cache(struct vc4_bo *bo)
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{
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struct drm_gem_object *obj = &bo->base.base;
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struct vc4_dev *vc4 = to_vc4_dev(obj->dev);
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vc4->bo_stats.num_cached--;
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vc4->bo_stats.size_cached -= obj->size;
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list_del(&bo->unref_head);
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list_del(&bo->size_head);
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}
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static struct list_head *vc4_get_cache_list_for_size(struct drm_device *dev,
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size_t size)
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{
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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uint32_t page_index = bo_page_index(size);
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if (vc4->bo_cache.size_list_size <= page_index) {
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uint32_t new_size = max(vc4->bo_cache.size_list_size * 2,
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page_index + 1);
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struct list_head *new_list;
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uint32_t i;
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new_list = kmalloc_array(new_size, sizeof(struct list_head),
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GFP_KERNEL);
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if (!new_list)
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return NULL;
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/* Rebase the old cached BO lists to their new list
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* head locations.
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*/
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for (i = 0; i < vc4->bo_cache.size_list_size; i++) {
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struct list_head *old_list =
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&vc4->bo_cache.size_list[i];
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if (list_empty(old_list))
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INIT_LIST_HEAD(&new_list[i]);
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else
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list_replace(old_list, &new_list[i]);
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}
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/* And initialize the brand new BO list heads. */
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for (i = vc4->bo_cache.size_list_size; i < new_size; i++)
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INIT_LIST_HEAD(&new_list[i]);
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kfree(vc4->bo_cache.size_list);
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vc4->bo_cache.size_list = new_list;
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vc4->bo_cache.size_list_size = new_size;
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}
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return &vc4->bo_cache.size_list[page_index];
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}
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void vc4_bo_cache_purge(struct drm_device *dev)
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{
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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mutex_lock(&vc4->bo_lock);
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while (!list_empty(&vc4->bo_cache.time_list)) {
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struct vc4_bo *bo = list_last_entry(&vc4->bo_cache.time_list,
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struct vc4_bo, unref_head);
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vc4_bo_remove_from_cache(bo);
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vc4_bo_destroy(bo);
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}
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mutex_unlock(&vc4->bo_lock);
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}
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static struct vc4_bo *vc4_bo_get_from_cache(struct drm_device *dev,
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uint32_t size)
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{
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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uint32_t page_index = bo_page_index(size);
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struct vc4_bo *bo = NULL;
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size = roundup(size, PAGE_SIZE);
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mutex_lock(&vc4->bo_lock);
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if (page_index >= vc4->bo_cache.size_list_size)
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goto out;
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if (list_empty(&vc4->bo_cache.size_list[page_index]))
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goto out;
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bo = list_first_entry(&vc4->bo_cache.size_list[page_index],
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struct vc4_bo, size_head);
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vc4_bo_remove_from_cache(bo);
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kref_init(&bo->base.base.refcount);
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out:
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mutex_unlock(&vc4->bo_lock);
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return bo;
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}
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/**
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* vc4_gem_create_object - Implementation of driver->gem_create_object.
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*
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* This lets the CMA helpers allocate object structs for us, and keep
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* our BO stats correct.
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*/
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struct drm_gem_object *vc4_create_object(struct drm_device *dev, size_t size)
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{
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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struct vc4_bo *bo;
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bo = kzalloc(sizeof(*bo), GFP_KERNEL);
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if (!bo)
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return ERR_PTR(-ENOMEM);
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mutex_lock(&vc4->bo_lock);
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vc4->bo_stats.num_allocated++;
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vc4->bo_stats.size_allocated += size;
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mutex_unlock(&vc4->bo_lock);
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return &bo->base.base;
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}
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struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size,
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bool from_cache)
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{
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size_t size = roundup(unaligned_size, PAGE_SIZE);
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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struct drm_gem_cma_object *cma_obj;
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cma_obj = drm_gem_cma_create(dev, size);
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if (IS_ERR(cma_obj))
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if (size == 0)
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return NULL;
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else
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return to_vc4_bo(&cma_obj->base);
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/* First, try to get a vc4_bo from the kernel BO cache. */
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if (from_cache) {
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struct vc4_bo *bo = vc4_bo_get_from_cache(dev, size);
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if (bo)
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return bo;
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}
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cma_obj = drm_gem_cma_create(dev, size);
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if (IS_ERR(cma_obj)) {
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/*
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* If we've run out of CMA memory, kill the cache of
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* CMA allocations we've got laying around and try again.
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*/
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vc4_bo_cache_purge(dev);
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cma_obj = drm_gem_cma_create(dev, size);
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if (IS_ERR(cma_obj)) {
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DRM_ERROR("Failed to allocate from CMA:\n");
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vc4_bo_stats_dump(vc4);
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return NULL;
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}
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}
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return to_vc4_bo(&cma_obj->base);
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}
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int vc4_dumb_create(struct drm_file *file_priv,
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@ -41,7 +251,7 @@ int vc4_dumb_create(struct drm_file *file_priv,
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if (args->size < args->pitch * args->height)
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args->size = args->pitch * args->height;
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bo = vc4_bo_create(dev, roundup(args->size, PAGE_SIZE));
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bo = vc4_bo_create(dev, args->size, false);
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if (!bo)
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return -ENOMEM;
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@ -50,3 +260,117 @@ int vc4_dumb_create(struct drm_file *file_priv,
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return ret;
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}
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/* Must be called with bo_lock held. */
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static void vc4_bo_cache_free_old(struct drm_device *dev)
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{
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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unsigned long expire_time = jiffies - msecs_to_jiffies(1000);
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while (!list_empty(&vc4->bo_cache.time_list)) {
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struct vc4_bo *bo = list_last_entry(&vc4->bo_cache.time_list,
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struct vc4_bo, unref_head);
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if (time_before(expire_time, bo->free_time)) {
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mod_timer(&vc4->bo_cache.time_timer,
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round_jiffies_up(jiffies +
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msecs_to_jiffies(1000)));
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return;
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}
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vc4_bo_remove_from_cache(bo);
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vc4_bo_destroy(bo);
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}
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}
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/* Called on the last userspace/kernel unreference of the BO. Returns
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* it to the BO cache if possible, otherwise frees it.
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*
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* Note that this is called with the struct_mutex held.
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*/
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void vc4_free_object(struct drm_gem_object *gem_bo)
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{
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struct drm_device *dev = gem_bo->dev;
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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struct vc4_bo *bo = to_vc4_bo(gem_bo);
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struct list_head *cache_list;
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mutex_lock(&vc4->bo_lock);
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/* If the object references someone else's memory, we can't cache it.
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*/
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if (gem_bo->import_attach) {
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vc4_bo_destroy(bo);
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goto out;
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}
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/* Don't cache if it was publicly named. */
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if (gem_bo->name) {
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vc4_bo_destroy(bo);
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goto out;
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}
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cache_list = vc4_get_cache_list_for_size(dev, gem_bo->size);
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if (!cache_list) {
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vc4_bo_destroy(bo);
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goto out;
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}
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bo->free_time = jiffies;
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list_add(&bo->size_head, cache_list);
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list_add(&bo->unref_head, &vc4->bo_cache.time_list);
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vc4->bo_stats.num_cached++;
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vc4->bo_stats.size_cached += gem_bo->size;
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vc4_bo_cache_free_old(dev);
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out:
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mutex_unlock(&vc4->bo_lock);
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}
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static void vc4_bo_cache_time_work(struct work_struct *work)
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{
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struct vc4_dev *vc4 =
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container_of(work, struct vc4_dev, bo_cache.time_work);
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struct drm_device *dev = vc4->dev;
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mutex_lock(&vc4->bo_lock);
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vc4_bo_cache_free_old(dev);
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mutex_unlock(&vc4->bo_lock);
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}
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static void vc4_bo_cache_time_timer(unsigned long data)
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{
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struct drm_device *dev = (struct drm_device *)data;
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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schedule_work(&vc4->bo_cache.time_work);
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}
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void vc4_bo_cache_init(struct drm_device *dev)
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{
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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mutex_init(&vc4->bo_lock);
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INIT_LIST_HEAD(&vc4->bo_cache.time_list);
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INIT_WORK(&vc4->bo_cache.time_work, vc4_bo_cache_time_work);
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setup_timer(&vc4->bo_cache.time_timer,
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vc4_bo_cache_time_timer,
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(unsigned long)dev);
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}
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void vc4_bo_cache_destroy(struct drm_device *dev)
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{
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struct vc4_dev *vc4 = to_vc4_dev(dev);
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del_timer(&vc4->bo_cache.time_timer);
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cancel_work_sync(&vc4->bo_cache.time_work);
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vc4_bo_cache_purge(dev);
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if (vc4->bo_stats.num_allocated) {
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DRM_ERROR("Destroying BO cache while BOs still allocated:\n");
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vc4_bo_stats_dump(vc4);
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}
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}
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@ -16,6 +16,7 @@
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#include "vc4_regs.h"
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static const struct drm_info_list vc4_debugfs_list[] = {
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{"bo_stats", vc4_bo_stats_debugfs, 0},
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{"hdmi_regs", vc4_hdmi_debugfs_regs, 0},
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{"hvs_regs", vc4_hvs_debugfs_regs, 0},
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{"crtc0_regs", vc4_crtc_debugfs_regs, 0, (void *)(uintptr_t)0},
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@ -92,7 +92,8 @@ static struct drm_driver vc4_drm_driver = {
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.debugfs_cleanup = vc4_debugfs_cleanup,
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#endif
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.gem_free_object = drm_gem_cma_free_object,
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.gem_create_object = vc4_create_object,
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.gem_free_object = vc4_free_object,
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.gem_vm_ops = &drm_gem_cma_vm_ops,
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.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
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@ -170,6 +171,8 @@ static int vc4_drm_bind(struct device *dev)
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drm_dev_set_unique(drm, dev_name(dev));
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vc4_bo_cache_init(drm);
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drm_mode_config_init(drm);
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if (ret)
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goto unref;
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@ -202,6 +205,7 @@ static int vc4_drm_bind(struct device *dev)
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component_unbind_all(dev, drm);
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unref:
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drm_dev_unref(drm);
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vc4_bo_cache_destroy(drm);
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return ret;
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}
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@ -17,6 +17,37 @@ struct vc4_dev {
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struct vc4_crtc *crtc[3];
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struct drm_fbdev_cma *fbdev;
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/* The kernel-space BO cache. Tracks buffers that have been
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* unreferenced by all other users (refcounts of 0!) but not
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* yet freed, so we can do cheap allocations.
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*/
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struct vc4_bo_cache {
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/* Array of list heads for entries in the BO cache,
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* based on number of pages, so we can do O(1) lookups
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* in the cache when allocating.
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*/
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struct list_head *size_list;
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uint32_t size_list_size;
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/* List of all BOs in the cache, ordered by age, so we
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* can do O(1) lookups when trying to free old
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* buffers.
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*/
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struct list_head time_list;
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struct work_struct time_work;
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struct timer_list time_timer;
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} bo_cache;
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struct vc4_bo_stats {
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u32 num_allocated;
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u32 size_allocated;
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u32 num_cached;
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u32 size_cached;
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} bo_stats;
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/* Protects bo_cache and the BO stats. */
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struct mutex bo_lock;
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};
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static inline struct vc4_dev *
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@ -27,6 +58,17 @@ to_vc4_dev(struct drm_device *dev)
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struct vc4_bo {
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struct drm_gem_cma_object base;
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/* List entry for the BO's position in either
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* vc4_exec_info->unref_list or vc4_dev->bo_cache.time_list
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*/
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||||
struct list_head unref_head;
|
||||
|
||||
/* Time in jiffies when the BO was put in vc4->bo_cache. */
|
||||
unsigned long free_time;
|
||||
|
||||
/* List entry for the BO's position in vc4_dev->bo_cache.size_list */
|
||||
struct list_head size_head;
|
||||
};
|
||||
|
||||
static inline struct vc4_bo *
|
||||
|
|
@ -104,13 +146,18 @@ to_vc4_encoder(struct drm_encoder *encoder)
|
|||
#define wait_for(COND, MS) _wait_for(COND, MS, 1)
|
||||
|
||||
/* vc4_bo.c */
|
||||
struct drm_gem_object *vc4_create_object(struct drm_device *dev, size_t size);
|
||||
void vc4_free_object(struct drm_gem_object *gem_obj);
|
||||
struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t size);
|
||||
struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t size,
|
||||
bool from_cache);
|
||||
int vc4_dumb_create(struct drm_file *file_priv,
|
||||
struct drm_device *dev,
|
||||
struct drm_mode_create_dumb *args);
|
||||
struct dma_buf *vc4_prime_export(struct drm_device *dev,
|
||||
struct drm_gem_object *obj, int flags);
|
||||
void vc4_bo_cache_init(struct drm_device *dev);
|
||||
void vc4_bo_cache_destroy(struct drm_device *dev);
|
||||
int vc4_bo_stats_debugfs(struct seq_file *m, void *arg);
|
||||
|
||||
/* vc4_crtc.c */
|
||||
extern struct platform_driver vc4_crtc_driver;
|
||||
|
|
|
|||
Loading…
Reference in a new issue