Author: alc
Date: Wed Dec 28 20:27:18 2011
New Revision: 228936
URL: http://svn.freebsd.org/changeset/base/228936
Log:
Optimize vm_object_split()'s handling of reservations.
Modified:
head/sys/vm/vm_object.c
Modified: head/sys/vm/vm_object.c
==============================================================================
--- head/sys/vm/vm_object.c Wed Dec 28 19:59:54 2011 (r228935)
+++ head/sys/vm/vm_object.c Wed Dec 28 20:27:18 2011 (r228936)
@@ -1323,6 +1323,21 @@ retry:
VM_OBJECT_LOCK(new_object);
goto retry;
}
+#if VM_NRESERVLEVEL > 0
+ /*
+ * If some of the reservation's allocated pages remain with
+ * the original object, then transferring the reservation to
+ * the new object is neither particularly beneficial nor
+ * particularly harmful as compared to leaving the reservation
+ * with the original object. If, however, all of the
+ * reservation's allocated pages are transferred to the new
+ * object, then transferring the reservation is typically
+ * beneficial. Determining which of these two cases applies
+ * would be more costly than unconditionally renaming the
+ * reservation.
+ */
+ vm_reserv_rename(m, new_object, orig_object, offidxstart);
+#endif
vm_page_lock(m);
vm_page_rename(m, new_object, idx);
vm_page_unlock(m);
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