1920     return;
1921   }
1922 
1923   g1h->verify_region_sets_optional();
1924 
1925   if (VerifyDuringGC) {
1926     HandleMark hm;  // handle scope
1927     g1h->prepare_for_verify();
1928     Universe::verify(VerifyOption_G1UsePrevMarking,
1929                      " VerifyDuringGC:(before)");
1930   }
1931   g1h->check_bitmaps("Cleanup Start");
1932 
1933   G1CollectorPolicy* g1p = g1h->g1_policy();
1934   g1p->record_concurrent_mark_cleanup_start();
1935 
1936   double start = os::elapsedTime();
1937 
1938   HeapRegionRemSet::reset_for_cleanup_tasks();
1939 
1940   uint n_workers;
1941 
1942   // Do counting once more with the world stopped for good measure.
1943   G1ParFinalCountTask g1_par_count_task(g1h, &_region_bm, &_card_bm);
1944 
1945   g1h->set_par_threads();
1946   n_workers = g1h->n_par_threads();
1947   assert(g1h->n_par_threads() == n_workers,
1948          "Should not have been reset");
1949   g1h->workers()->run_task(&g1_par_count_task);
1950   // Done with the parallel phase so reset to 0.
1951   g1h->set_par_threads(0);
1952 
1953   if (VerifyDuringGC) {
1954     // Verify that the counting data accumulated during marking matches
1955     // that calculated by walking the marking bitmap.
1956 
1957     // Bitmaps to hold expected values
1958     BitMap expected_region_bm(_region_bm.size(), true);
1959     BitMap expected_card_bm(_card_bm.size(), true);
1960 
1961     G1ParVerifyFinalCountTask g1_par_verify_task(g1h,
1962                                                  &_region_bm,
1963                                                  &_card_bm,
1964                                                  &expected_region_bm,
1965                                                  &expected_card_bm);
1966 
1967     g1h->set_par_threads((int)n_workers);
1968     g1h->workers()->run_task(&g1_par_verify_task);

1920     return;
1921   }
1922 
1923   g1h->verify_region_sets_optional();
1924 
1925   if (VerifyDuringGC) {
1926     HandleMark hm;  // handle scope
1927     g1h->prepare_for_verify();
1928     Universe::verify(VerifyOption_G1UsePrevMarking,
1929                      " VerifyDuringGC:(before)");
1930   }
1931   g1h->check_bitmaps("Cleanup Start");
1932 
1933   G1CollectorPolicy* g1p = g1h->g1_policy();
1934   g1p->record_concurrent_mark_cleanup_start();
1935 
1936   double start = os::elapsedTime();
1937 
1938   HeapRegionRemSet::reset_for_cleanup_tasks();
1939 


1940   // Do counting once more with the world stopped for good measure.
1941   G1ParFinalCountTask g1_par_count_task(g1h, &_region_bm, &_card_bm);
1942 
1943   g1h->set_par_threads();
1944   uint n_workers = _g1h->workers()->active_workers();


1945   g1h->workers()->run_task(&g1_par_count_task);
1946   // Done with the parallel phase so reset to 0.
1947   g1h->set_par_threads(0);
1948 
1949   if (VerifyDuringGC) {
1950     // Verify that the counting data accumulated during marking matches
1951     // that calculated by walking the marking bitmap.
1952 
1953     // Bitmaps to hold expected values
1954     BitMap expected_region_bm(_region_bm.size(), true);
1955     BitMap expected_card_bm(_card_bm.size(), true);
1956 
1957     G1ParVerifyFinalCountTask g1_par_verify_task(g1h,
1958                                                  &_region_bm,
1959                                                  &_card_bm,
1960                                                  &expected_region_bm,
1961                                                  &expected_card_bm);
1962 
1963     g1h->set_par_threads((int)n_workers);
1964     g1h->workers()->run_task(&g1_par_verify_task);