-/* Should we filter stack/register pointers? This could reduce the
- * number of invalid pointers accepted. KLUDGE: It will probably
- * degrades interrupt safety during object initialization. */
+/* Should we filter stack/register pointers? This substantially reduces the
+ * number of invalid pointers accepted.
+ *
+ * FIXME: This is basically constant=1. It will probably degrade
+ * interrupt safety during object initialization. But I don't think we
+ * should do without it -- the possibility of the GC being too
+ * conservative and hence running out of memory is also. Perhaps the
+ * interrupt safety issue could be fixed by making the initialization
+ * code do WITHOUT-GCING or WITHOUT-INTERRUPTS until the appropriate
+ * type bits have been set. (That might be necessary anyway, in order
+ * to keep interrupt code's allocation operations from stepping on the
+ * interrupted code's allocations.) Or perhaps it could be fixed by
+ * making sure that uninitialized memory is zero, reserving the
+ * all-zero case for uninitialized memory, and making the
+ * is-it-possibly-a-valid-pointer code check for all-zero and return
+ * true in that case. Then after either fix, we could get rid of this
+ * variable and simply hardwire the system always to do pointer
+ * filtering. */