EXA: Allocate from the end of free offscreen memory rather than from the start.

This way we don't always need to scan over previously allocated areas when
looking for an available one, and there might be less fragmentation.

Signed-off-by: Michel Dänzer <daenzer@vmware.com>

1 files changed, 14 insertions, 31 deletions

diff --git a/exa/exa_offscreen.c b/exa/exa_offscreen.c
index 043fd83ae..eb53b2a30 100644
--- a/exa/exa_offscreen.c
+++ b/exa/exa_offscreen.c
@@ -93,7 +93,7 @@ exaFindAreaToEvict(ExaScreenPrivPtr pExaScr, int size, int align)
 {
     ExaOffscreenArea *begin, *end, *best;
     unsigned cost, best_cost;
-    int avail, real_size, tmp;
+    int avail, real_size;
 
     best_cost = UINT_MAX;
     begin = end = pExaScr->info->offScreenAreas;
@@ -111,10 +111,7 @@ exaFindAreaToEvict(ExaScreenPrivPtr pExaScr, int size, int align)
 	    break;
 
 	/* adjust size needed to account for alignment loss for this area */
-	real_size = size;
-	tmp = begin->base_offset % align;
-	if (tmp)
-	    real_size += (align - tmp);
+	real_size = size + (begin->base_offset + begin->size - size) % align;
 
 	while (avail < real_size && end != NULL)
 	{
@@ -172,7 +169,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
 {
     ExaOffscreenArea *area;
     ExaScreenPriv (pScreen);
-    int tmp, real_size = 0, free_total = 0, largest_avail = 0;
+    int real_size = 0, free_total = 0, largest_avail = 0;
 #if DEBUG_OFFSCREEN
     static int number = 0;
     ErrorF("================= ============ allocating a new pixmap %d\n", ++number);
@@ -205,10 +202,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
 	    continue;
 
 	/* adjust size to match alignment requirement */
-	real_size = size;
-	tmp = area->base_offset % align;
-	if (tmp)
-	    real_size += (align - tmp);
+	real_size = size + (area->base_offset + area->size - size) % align;
 
 	/* does it fit? */
 	if (real_size <= area->size)
@@ -232,10 +226,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
 
 	    if (area) {
 		/* adjust size to match alignment requirement */
-		real_size = size;
-		tmp = area->base_offset % align;
-		if (tmp)
-		    real_size += (align - tmp);
+		real_size = size + (area->base_offset + area->size - size) % align;
 
 		/* does it fit? */
 		if (real_size > area->size)
@@ -257,10 +248,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
 	}
 
 	/* adjust size needed to account for alignment loss for this area */
-	real_size = size;
-	tmp = area->base_offset % align;
-	if (tmp)
-	    real_size += (align - tmp);
+	real_size = size + (area->base_offset + area->size - size) % align;
 
 	/*
 	 * Kick out first area if in use
@@ -283,13 +271,7 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
 	ExaOffscreenArea   *new_area = xalloc (sizeof (ExaOffscreenArea));
 	if (!new_area)
 	    return NULL;
-	new_area->base_offset = area->base_offset + real_size;
-
-#if DEBUG_OFFSCREEN
-	if (new_area->base_offset >= pExaScr->info->memorySize)
-	    ErrorF("new_area->base_offset = 0x%08x >= memorySize!\n",
-		   new_area->base_offset);
-#endif
+	new_area->base_offset = area->base_offset;
 
 	new_area->offset = new_area->base_offset;
 	new_area->align = 0;
@@ -298,13 +280,14 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
 	new_area->save = NULL;
 	new_area->last_use = 0;
 	new_area->eviction_cost = 0;
-	new_area->next = area->next;
-	if (area->next)
-	    area->next->prev = new_area;
+	new_area->next = area;
+	new_area->prev = area->prev;
+	if (area->prev->next)
+	    area->prev->next = new_area;
 	else
-	    pExaScr->info->offScreenAreas->prev = new_area;
-	area->next = new_area;
-	new_area->prev = area;
+	    pExaScr->info->offScreenAreas = new_area;
+	area->prev = new_area;
+	area->base_offset = new_area->base_offset + new_area->size;
 	area->size = real_size;
     } else
 	pExaScr->numOffscreenAvailable--;