Update src/alloc/isolated_alloc.rs

Co-authored-by: Ralf Jung <post@ralfj.de>

Author: nia-e

src/alloc/isolated_alloc.rs

@@ -120,7 +120,9 @@ impl IsolatedAlloc {
             if pinfo.domain_size() < idx_pinfo + size_pinfo {
                 break;
             }
-            let pred = !(idx_pinfo..idx_pinfo + size_pinfo).any(|idx| pinfo.contains(idx));
+            // FIXME: is there a more efficient way to check whether the entire range is unset
+            // in the bitset?
+            let range_avail = !(idx_pinfo..idx_pinfo + size_pinfo).any(|idx| pinfo.contains(idx));
             if pred {
                 pinfo.insert_range(idx_pinfo..idx_pinfo + size_pinfo);
                 unsafe {