From: jsg <jsg@openbsd.org>
Date: Fri, 12 May 2023 11:16:58 +0000 (+0000)
Subject: drm/ttm: optimize pool allocations a bit v2
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=d641b4f9832202e5774e762676f50de17411b5f5;p=openbsd

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 e47829c9651..799112bec2b 100644
--- 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;
 		}
 	}