drm/ttm: optimize pool allocations a bit v2

From Christian Koenig
5e5a4185c66f9478a8cb2f74eed1a5b5a5000b13 in linux-6.1.y/6.1.28
735c466465eba51deaee3012d8403c10fc7c8c03 in mainline linux

diff --git a/sys/dev/pci/drm/ttm/ttm_pool.c b/sys/dev/pci/drm/ttm/ttm_pool.c
index e47829c..799112b 100644 (file)
--- a/sys/dev/pci/drm/ttm/ttm_pool.c
+++ b/sys/dev/pci/drm/ttm/ttm_pool.c
@@ -485,6 +485,31 @@ static unsigned int ttm_pool_page_order(struct ttm_pool *pool, struct vm_page *p
 
 #endif /* notyet */
 
+/* Called when we got a page, either from a pool or newly allocated */
+static int ttm_pool_page_allocated(struct ttm_pool *pool, unsigned int order,
+                                  struct vm_page *p, dma_addr_t **dma_addr,
+                                  unsigned long *num_pages,
+                                  struct vm_page ***pages,
+                                  unsigned long **orders)
+{
+       unsigned int i;
+       int r;
+
+       if (*dma_addr) {
+               r = ttm_pool_map(pool, order, p, dma_addr);
+               if (r)
+                       return r;
+       }
+
+       *num_pages -= 1 << order;
+       for (i = 1 << order; i; --i, ++(*pages), ++p, ++(*orders)) {
+               **pages = p;
+               **orders = order;
+       }
+
+       return 0;
+}
+
 /**
  * ttm_pool_alloc - Fill a ttm_tt object
  *
@@ -529,46 +554,56 @@ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
        for (order = min_t(unsigned int, MAX_ORDER - 1, __fls(num_pages));
             num_pages;
             order = min_t(unsigned int, order, __fls(num_pages))) {
-               bool apply_caching = false;
                struct ttm_pool_type *pt;
 
                pt = ttm_pool_select_type(pool, tt->caching, order);
                p = pt ? ttm_pool_type_take(pt) : NULL;
                if (p) {
-                       apply_caching = true;
-               } else {
-                       p = ttm_pool_alloc_page(pool, gfp_flags, order, tt->dmat);
-                       if (p && PageHighMem(p))
-                               apply_caching = true;
-               }
-
-               if (!p) {
-                       if (order) {
-                               --order;
-                               continue;
-                       }
-                       r = -ENOMEM;
-                       goto error_free_all;
-               }
-
-               if (apply_caching) {
                        r = ttm_pool_apply_caching(caching, pages,
                                                   tt->caching);
                        if (r)
                                goto error_free_page;
-                       caching = pages + (1 << order);
+
+                       do {
+                               r = ttm_pool_page_allocated(pool, order, p,
+                                                           &dma_addr,
+                                                           &num_pages,
+                                                           &pages, &orders);
+                               if (r)
+                                       goto error_free_page;
+
+                               if (num_pages < (1 << order))
+                                       break;
+
+                               p = ttm_pool_type_take(pt);
+                       } while (p);
+                       caching = pages;
                }
 
-               if (dma_addr) {
-                       r = ttm_pool_map(pool, order, p, &dma_addr);
+               while (num_pages >= (1 << order) &&
+                      (p = ttm_pool_alloc_page(pool, gfp_flags, order, tt->dmat))) {
+
+                       if (PageHighMem(p)) {
+                               r = ttm_pool_apply_caching(caching, pages,
+                                                          tt->caching);
+                               if (r)
+                                       goto error_free_page;
+                       }
+                       r = ttm_pool_page_allocated(pool, order, p, &dma_addr,
+                                                   &num_pages, &pages, &orders);
                        if (r)
                                goto error_free_page;
+                       if (PageHighMem(p))
+                               caching = pages;
                }
 
-               num_pages -= 1 << order;
-               for (i = 1 << order; i; --i) {
-                       *(pages++) = p++;
-                       *(orders++) = order;
+               if (!p) {
+                       if (order) {
+                               --order;
+                               continue;
+                       }
+                       r = -ENOMEM;
+                       goto error_free_all;
                }
        }