void CardTableRS::clear_into_younger(Generation* gen, bool clear_perm) { GenCollectedHeap* gch = GenCollectedHeap::heap(); // Generations younger than gen have been evacuated. We can clear // card table entries for gen (we know that it has no pointers // to younger gens) and for those below. The card tables for // the youngest gen need never be cleared, and those for perm gen // will be cleared based on the parameter clear_perm. // There's a bit of subtlety in the clear() and invalidate() // methods that we exploit here and in invalidate_or_clear() // below to avoid missing cards at the fringes. If clear() or // invalidate() are changed in the future, this code should // be revisited. 20040107.ysr Generation* g = gen; for(Generation* prev_gen = gch->prev_gen(g); prev_gen != NULL; g = prev_gen, prev_gen = gch->prev_gen(g)) { MemRegion to_be_cleared_mr = g->prev_used_region(); clear(to_be_cleared_mr); } // Clear perm gen cards if asked to do so. if (clear_perm) { MemRegion to_be_cleared_mr = gch->perm_gen()->prev_used_region(); clear(to_be_cleared_mr); } }
void CardTableRS::invalidate_or_clear(Generation* gen, bool younger, bool perm) { GenCollectedHeap* gch = GenCollectedHeap::heap(); // For each generation gen (and younger and/or perm) // invalidate the cards for the currently occupied part // of that generation and clear the cards for the // unoccupied part of the generation (if any, making use // of that generation's prev_used_region to determine that // region). No need to do anything for the youngest // generation. Also see note#20040107.ysr above. Generation* g = gen; for(Generation* prev_gen = gch->prev_gen(g); prev_gen != NULL; g = prev_gen, prev_gen = gch->prev_gen(g)) { MemRegion used_mr = g->used_region(); MemRegion to_be_cleared_mr = g->prev_used_region().minus(used_mr); if (!to_be_cleared_mr.is_empty()) { clear(to_be_cleared_mr); } invalidate(used_mr); if (!younger) break; } // Clear perm gen cards if asked to do so. if (perm) { g = gch->perm_gen(); MemRegion used_mr = g->used_region(); MemRegion to_be_cleared_mr = g->prev_used_region().minus(used_mr); if (!to_be_cleared_mr.is_empty()) { clear(to_be_cleared_mr); } invalidate(used_mr); } }
void CardTableRS::clear_into_gen_and_younger(Generation* gen) { GenCollectedHeap* gch = GenCollectedHeap::heap(); // Gen and all younger have been evacuated. We can clear // remembered set entries for the next highest generation // (we know that it has no pointers to younger gens) and // those below. Generation* g = gch->next_gen(gen); while (g != NULL) { clear(g->reserved()); g = gch->prev_gen(gen); } }