Re: [PATCH 2/4] drm/ttm: replace drm_mm_pre_get() by direct alloc

On Thu, Jul 25, 2013 at 03:56:00PM +0200, David Herrmann wrote:

Instead of calling drm_mm_pre_get() in a row, we now preallocate the node and then use the atomic insertion functions. This has the exact same semantics and there is no reason to use the racy pre-allocations.

Note that ttm_bo_man_get_node() does not run in atomic context. Nouveau already uses GFP_KERNEL alloc in nouveau/nouveau_ttm.c in nouveau_gart_manager_new(). So we can do the same in ttm_bo_man_get_node().

Signed-off-by: David Herrmann dh.herrmann@gmail.com

Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch

---

drivers/gpu/drm/ttm/ttm_bo_manager.c | 40 +++++++++++++++++------------------- 1 file changed, 19 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo_manager.c b/drivers/gpu/drm/ttm/ttm_bo_manager.c index e4367f9..cbd2ec7 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_manager.c +++ b/drivers/gpu/drm/ttm/ttm_bo_manager.c @@ -61,28 +61,24 @@ static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man, lpfn = placement->lpfn; if (!lpfn) lpfn = man->size;

• do {

• ret = drm_mm_pre_get(mm);
  

• if (unlikely(ret))
  

• 	return ret;
  
  

• spin_lock(&rman->lock);
  

• node = drm_mm_search_free_in_range(mm,
  

• 			mem->num_pages, mem->page_alignment,
  

• 			placement->fpfn, lpfn, 1);
  

• if (unlikely(node == NULL)) {
  

• 	spin_unlock(&rman->lock);
  

• 	return 0;
  

• }
  

• node = drm_mm_get_block_atomic_range(node, mem->num_pages,
  

• 				     mem->page_alignment,
  

• 				     placement->fpfn,
  

• 				     lpfn);
  

• spin_unlock(&rman->lock);
  

• } while (node == NULL);

• node = kzalloc(sizeof(*node), GFP_KERNEL);
• if (!node)

• return -ENOMEM;
  

• spin_lock(&rman->lock);
• ret = drm_mm_insert_node_in_range(mm, node, mem->num_pages,

• 			  mem->page_alignment,
  

• 			  placement->fpfn, lpfn, true);
  

• spin_unlock(&rman->lock);
• if (unlikely(ret)) {

• kfree(node);
  

• } else {

• mem->mm_node = node;
  

• mem->start = node->start;
  

• }

• mem->mm_node = node;
• mem->start = node->start; return 0;

}

@@ -93,8 +89,10 @@ static void ttm_bo_man_put_node(struct ttm_mem_type_manager *man,

if (mem->mm_node) { spin_lock(&rman->lock);

• drm_mm_put_block(mem->mm_node);
  

• drm_mm_remove_node(mem->mm_node);
  

  spin_unlock(&rman->lock);

• kfree(mem->mm_node);
  

  mem->mm_node = NULL; }

}

1.8.3.3