8033545: Missing volatile specifier in Bitmap::par_put_range_within_word
Summary: The method Bitmap::par_put_range_within_word reloads the original value during a CAS, which may be optimized away. Instead of reloading, use the value returned by Atomic::cmpxchg_ptr() for further processing.
Reviewed-by: tschatzl, brutisso, tonyp
Contributed-by: Matthias Braun <matthia.braun@sap.com>
--- a/hotspot/src/share/vm/utilities/bitMap.cpp Thu Feb 06 14:12:43 2014 +0100
+++ b/hotspot/src/share/vm/utilities/bitMap.cpp Thu Feb 06 17:12:10 2014 +0100
@@ -107,7 +107,7 @@
while (true) {
intptr_t res = Atomic::cmpxchg_ptr(nw, pw, w);
if (res == w) break;
- w = *pw;
+ w = res;
nw = value ? (w | ~mr) : (w & mr);
}
}