diff --git a/src/share/vm/runtime/sweeper.cpp b/src/share/vm/runtime/sweeper.cpp index 9034428173e9a366efe8d9d31837b00f966dd8f1..5632889ed979903c6d45f9ef81279bea19584e81 100644 --- a/src/share/vm/runtime/sweeper.cpp +++ b/src/share/vm/runtime/sweeper.cpp @@ -257,9 +257,14 @@ void NMethodSweeper::possibly_sweep() { // Large ReservedCodeCacheSize: (e.g., 256M + code Cache is 90% full). The formula // computes: (256 / 16) - 10 = 6. if (!_should_sweep) { - int time_since_last_sweep = _time_counter - _last_sweep; - double wait_until_next_sweep = (ReservedCodeCacheSize / (16 * M)) - time_since_last_sweep - - CodeCache::reverse_free_ratio(); + const int time_since_last_sweep = _time_counter - _last_sweep; + // ReservedCodeCacheSize has an 'unsigned' type. We need a 'signed' type for max_wait_time, + // since 'time_since_last_sweep' can be larger than 'max_wait_time'. If that happens using + // an unsigned type would cause an underflow (wait_until_next_sweep becomes a large positive + // value) that disables the intended periodic sweeps. + const int max_wait_time = ReservedCodeCacheSize / (16 * M); + double wait_until_next_sweep = max_wait_time - time_since_last_sweep - CodeCache::reverse_free_ratio(); + assert(wait_until_next_sweep <= (double)max_wait_time, "Calculation of code cache sweeper interval is incorrect"); if ((wait_until_next_sweep <= 0.0) || !CompileBroker::should_compile_new_jobs()) { _should_sweep = true;