Re: [PATCH 7/8] drm/ttm: Introduce a huge page aligning TTM range manager.

Am 03.12.19 um 14:22 schrieb Thomas Hellström (VMware):

From: Thomas Hellstrom thellstrom@vmware.com

Using huge page-table entries require that the start of a buffer object is huge page size aligned. So introduce a ttm_bo_man_get_node_huge() function that attempts to accomplish this for allocations that are larger than the huge page size, and provide a new range-manager instance that uses that function.

I still don't think that this is a good idea.

The driver/userspace should just use a proper alignment if it wants to use huge pages.

Regards, Christian.

Cc: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: "Matthew Wilcox (Oracle)" willy@infradead.org Cc: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Cc: Ralph Campbell rcampbell@nvidia.com Cc: "Jérôme Glisse" jglisse@redhat.com Cc: "Christian König" christian.koenig@amd.com Signed-off-by: Thomas Hellstrom thellstrom@vmware.com

---

drivers/gpu/drm/ttm/ttm_bo_manager.c | 92 ++++++++++++++++++++++++++++ include/drm/ttm/ttm_bo_driver.h | 1 + 2 files changed, 93 insertions(+)

diff --git a/drivers/gpu/drm/ttm/ttm_bo_manager.c b/drivers/gpu/drm/ttm/ttm_bo_manager.c index 18d3debcc949..26aa1a2ae7f1 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_manager.c +++ b/drivers/gpu/drm/ttm/ttm_bo_manager.c @@ -89,6 +89,89 @@ static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man, return 0; }

+#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static int ttm_bo_insert_aligned(struct drm_mm *mm, struct drm_mm_node *node,

• 		 unsigned long align_pages,
  

• 		 const struct ttm_place *place,
  

• 		 struct ttm_mem_reg *mem,
  

• 		 unsigned long lpfn,
  

• 		 enum drm_mm_insert_mode mode)
  

+{

• if (align_pages >= mem->page_alignment &&

•    (!mem->page_alignment || align_pages % mem->page_alignment == 0)) {
  

• return drm_mm_insert_node_in_range(mm, node,
  

• 				   mem->num_pages,
  

• 				   align_pages, 0,
  

• 				   place->fpfn, lpfn, mode);
  

• }
• return -ENOSPC;

+}

+static int ttm_bo_man_get_node_huge(struct ttm_mem_type_manager *man,

• 		    struct ttm_buffer_object *bo,
  

• 		    const struct ttm_place *place,
  

• 		    struct ttm_mem_reg *mem)
  

+{

• struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;
• struct drm_mm *mm = &rman->mm;
• struct drm_mm_node *node;
• unsigned long align_pages;
• unsigned long lpfn;
• enum drm_mm_insert_mode mode = DRM_MM_INSERT_BEST;
• int ret;
• node = kzalloc(sizeof(*node), GFP_KERNEL);
• if (!node)

• return -ENOMEM;
  

• lpfn = place->lpfn;
• if (!lpfn)

• lpfn = man->size;
  

• mode = DRM_MM_INSERT_BEST;
• if (place->flags & TTM_PL_FLAG_TOPDOWN)

• mode = DRM_MM_INSERT_HIGH;
  

• spin_lock(&rman->lock);
• if (IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)) {

• align_pages = (HPAGE_PUD_SIZE >> PAGE_SHIFT);
  

• if (mem->num_pages >= align_pages) {
  

• 	ret = ttm_bo_insert_aligned(mm, node, align_pages,
  

• 				    place, mem, lpfn, mode);
  

• 	if (!ret)
  

• 		goto found_unlock;
  

• }
  

• }
• align_pages = (HPAGE_PMD_SIZE >> PAGE_SHIFT);
• if (mem->num_pages >= align_pages) {

• ret = ttm_bo_insert_aligned(mm, node, align_pages, place, mem,
  

• 			    lpfn, mode);
  

• if (!ret)
  

• 	goto found_unlock;
  

• }
• ret = drm_mm_insert_node_in_range(mm, node, mem->num_pages,

• 			  mem->page_alignment, 0,
  

• 			  place->fpfn, lpfn, mode);
  

+found_unlock:

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

• kfree(node);
  

• } else {

• mem->mm_node = node;
  

• mem->start = node->start;
  

• }
• return 0;

+} +#else +#define ttm_bo_man_get_node_huge ttm_bo_man_get_node +#endif

• static void ttm_bo_man_put_node(struct ttm_mem_type_manager *man, struct ttm_mem_reg *mem) {

@@ -154,3 +237,12 @@ const struct ttm_mem_type_manager_func ttm_bo_manager_func = { .debug = ttm_bo_man_debug }; EXPORT_SYMBOL(ttm_bo_manager_func);

+const struct ttm_mem_type_manager_func ttm_bo_manager_huge_func = {

• .init = ttm_bo_man_init,
• .takedown = ttm_bo_man_takedown,
• .get_node = ttm_bo_man_get_node_huge,
• .put_node = ttm_bo_man_put_node,
• .debug = ttm_bo_man_debug

+}; +EXPORT_SYMBOL(ttm_bo_manager_huge_func); diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h index cac7a8a0825a..868bd0d4be6a 100644 --- a/include/drm/ttm/ttm_bo_driver.h +++ b/include/drm/ttm/ttm_bo_driver.h @@ -888,5 +888,6 @@ int ttm_bo_pipeline_gutting(struct ttm_buffer_object *bo); pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp);

extern const struct ttm_mem_type_manager_func ttm_bo_manager_func; +extern const struct ttm_mem_type_manager_func ttm_bo_manager_huge_func;

#endif