Add an additional meaning to the "dirty" flag. Now, if !dirty && !area, the

    pixmaps's contents are undefined, so we won't need to upload the
    undefined contents in MoveIn. Use the ExaCheck* for async ops as well,
    so that dirty is always tracked. While the performance impact for my ls
    -lR test was not significant (though the avoiding-upload path was being
    hit), it's likely to be important for the upcoming Get/PutImage
    acceleration from ajax.

1 files changed, 14 insertions, 0 deletions

diff --git a/hw/xfree86/exa/exa_accel.c b/hw/xfree86/exa/exa_accel.c
index 2b9dc63dd..c8e57e440 100644
--- a/hw/xfree86/exa/exa_accel.c
+++ b/hw/xfree86/exa/exa_accel.c
@@ -159,6 +159,10 @@ exaPixmapSave (ScreenPtr pScreen, ExaOffscreenArea *area)
     pPixmap->devPrivate.ptr = dst;
     pPixmap->drawable.serialNumber = NEXT_SERIAL_NUMBER;
     pExaPixmap->area = NULL;
+    /* Mark it dirty now, to say that there is important data in the
+     * system-memory copy.
+     */
+    pExaPixmap->dirty = TRUE;
 }
 
 static int
@@ -238,6 +242,16 @@ exaMoveInPixmap (PixmapPtr pPixmap)
 	return;
     }
 
+    /* If the "dirty" flag has never been set on the in-memory pixmap, then
+     * nothing has been written to it, so the contents are undefined and we can
+     * avoid the upload.
+     */
+    if (!pExaPixmap->dirty) {
+	DBG_MIGRATE(("saved upload of %dx%d\n", pPixmap->drawable.width,
+		     pPixmap->drawable.height));
+	return;
+    }
+
     pExaPixmap->dirty = FALSE;
 
     if (pExaScr->info->accel.UploadToScreen)