diff --git a/exa/exa_migration.c b/exa/exa_migration.c
index 3c79f68..9c22178 100644
--- a/exa/exa_migration.c
+++ b/exa/exa_migration.c
@@ -152,42 +152,45 @@ exaCopyDirty(ExaMigrationPtr migrate, RegionPtr pValidDst, RegionPtr pValidSrc,
     REGION_NULL(pScreen, &CopyReg);
     REGION_SUBTRACT(pScreen, &CopyReg, pValidSrc, pValidDst);
 
-    if (migrate->as_dst) {
-	ExaScreenPriv (pPixmap->drawable.pScreen);
-
-	/* XXX: The pending damage region will be marked as damaged after the
-	 * operation, so it should serve as an upper bound for the region that
-	 * needs to be synchronized for the operation. Unfortunately, this
-	 * causes corruption in some cases, e.g. when starting compiz. See
-	 * https://bugs.freedesktop.org/show_bug.cgi?id=12916 .
-	 */
-	if (pExaScr->optimize_migration) {
-	    RegionPtr pending_damage = DamagePendingRegion(pExaPixmap->pDamage);
-
-	    if (REGION_NIL(pending_damage)) {
-		static Bool firsttime = TRUE;
-
-		if (firsttime) {
-		    ErrorF("%s: Pending damage region empty!\n", __func__);
-		    firsttime = FALSE;
+    /* Try to prevent destination valid region from growing too many rects */
+    if (REGION_NUM_RECTS(pValidDst) < 10) {
+	if (migrate->as_dst) {
+	    ExaScreenPriv (pPixmap->drawable.pScreen);
+
+	    /* XXX: The pending damage region will be marked as damaged after the
+	     * operation, so it should serve as an upper bound for the region that
+	     * needs to be synchronized for the operation. Unfortunately, this
+	     * causes corruption in some cases, e.g. when starting compiz. See
+	     * https://bugs.freedesktop.org/show_bug.cgi?id=12916 .
+	     */
+	    if (pExaScr->optimize_migration) {
+		RegionPtr pending_damage = DamagePendingRegion(pExaPixmap->pDamage);
+
+		if (REGION_NIL(pending_damage)) {
+		    static Bool firsttime = TRUE;
+
+		    if (firsttime) {
+			ErrorF("%s: Pending damage region empty!\n", __func__);
+			firsttime = FALSE;
+		    }
 		}
+
+		REGION_INTERSECT(pScreen, &CopyReg, &CopyReg, pending_damage);
 	    }
 
-	    REGION_INTERSECT(pScreen, &CopyReg, &CopyReg, pending_damage);
+	    /* The caller may provide a region to be subtracted from the calculated
+	     * dirty region. This is to avoid migration of bits that don't
+	     * contribute to the result of the operation.
+	     */
+	    if (migrate->pReg)
+		REGION_SUBTRACT(pScreen, &CopyReg, &CopyReg, migrate->pReg);
+	} else {
+	    /* The caller may restrict the region to be migrated for source pixmaps
+	     * to what's relevant for the operation.
+	     */
+	    if (migrate->pReg)
+		REGION_INTERSECT(pScreen, &CopyReg, &CopyReg, migrate->pReg);
 	}
-
-	/* The caller may provide a region to be subtracted from the calculated
-	 * dirty region. This is to avoid migration of bits that don't
-	 * contribute to the result of the operation.
-	 */
-	if (migrate->pReg)
-	    REGION_SUBTRACT(pScreen, &CopyReg, &CopyReg, migrate->pReg);
-    } else {
-	/* The caller may restrict the region to be migrated for source pixmaps
-	 * to what's relevant for the operation.
-	 */
-	if (migrate->pReg)
-	    REGION_INTERSECT(pScreen, &CopyReg, &CopyReg, migrate->pReg);
     }
 
     pBox = REGION_RECTS(&CopyReg);
@@ -239,6 +242,10 @@ exaCopyDirty(ExaMigrationPtr migrate, RegionPtr pValidDst, RegionPtr pValidSrc,
     /* The copied bits are now valid in destination */
     REGION_UNION(pScreen, pValidDst, pValidDst, &CopyReg);
 
+    /* Try to prevent source valid region from growing too many rects */
+    if (REGION_NUM_RECTS(pValidSrc) > 10)
+	REGION_SUBTRACT(pScreen, pValidSrc, pValidSrc, pValidDst);
+
     REGION_UNINIT(pScreen, &CopyReg);
 }