diff mbox

[RFC,v5,04/86] memory: merge adjacent segments of a single memory region

Message ID 1311180636-17012-5-git-send-email-avi@redhat.com
State New
Headers show

Commit Message

Avi Kivity July 20, 2011, 4:49 p.m. UTC 
Simple implementations of memory routers, for example the Cirrus VGA memory banks
or the 440FX PAM registers can generate adjacent memory regions which are contiguous.
Detect these and merge them; this saves kvm memory slots and shortens lookup times.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 memory.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)
diff mbox

Patch

diff --git a/memory.c b/memory.c
index a569666..339bea3 100644
--- a/memory.c
+++ b/memory.c
@@ -122,6 +122,27 @@  static void flatview_destroy(FlatView *view)
     qemu_free(view->ranges);
 }
 
+/* Attempt to simplify a view by merging ajacent ranges */
+static void flatview_simplify(FlatView *view)
+{
+    unsigned i;
+    FlatRange *r1, *r2;
+
+    for (i = 0; i + 1 < view->nr; ++i) {
+        r1 = &view->ranges[i];
+        r2 = &view->ranges[i+1];
+        if (addrrange_end(r1->addr) == r2->addr.start
+            && r1->mr == r2->mr
+            && r1->offset_in_region + r1->addr.size == r2->offset_in_region
+            && r1->dirty_log_mask == r2->dirty_log_mask) {
+            r1->addr.size += r2->addr.size;
+            memmove(r2, r2 + 1, (view->nr - (i + 2)) * sizeof(*r2));
+            --view->nr;
+            --i;
+        }
+    }
+}
+
 /* Render a memory region into the global view.  Ranges in @view obscure
  * ranges in @mr.
  */
@@ -209,6 +230,7 @@  static FlatView generate_memory_topology(MemoryRegion *mr)
     flatview_init(&view);
 
     render_memory_region(&view, mr, 0, addrrange_make(0, UINT64_MAX));
+    flatview_simplify(&view);
 
     return view;
 }