src/share/vm/runtime/sweeper.hpp

*** 43,58 ****
  //     called at a safepoint. However, sweep_code_cache() stops executing if
  //     another thread requests a safepoint. Consequently, 'mark_active_nmethods()'
  //     and sweep_code_cache() cannot execute at the same time.
  //     To reclaim memory, nmethods are first marked as 'not-entrant'. Methods can
  //     be made not-entrant by (i) the sweeper, (ii) deoptimization, (iii) dependency
! //     invalidation, and (iv) being replaced be a different method version (tiered
! //     compilation). Not-entrant nmethod cannot be called by Java threads, but they
! //     can still be active on the stack. To ensure that active nmethod are not reclaimed,
  //     we have to wait until the next marking phase has completed. If a not-entrant
  //     nmethod was NOT marked as active, it can be converted to 'zombie' state. To safely
! //     remove the nmethod, all inline caches (IC) that point to the the nmethod must be
  //     cleared. After that, the nmethod can be evicted from the code cache. Each nmethod's
  //     state change happens during separate sweeps. It may take at least 3 sweeps before an
  //     nmethod's space is freed.
  
  class NMethodSweeper : public AllStatic {
--- 43,58 ----
  //     called at a safepoint. However, sweep_code_cache() stops executing if
  //     another thread requests a safepoint. Consequently, 'mark_active_nmethods()'
  //     and sweep_code_cache() cannot execute at the same time.
  //     To reclaim memory, nmethods are first marked as 'not-entrant'. Methods can
  //     be made not-entrant by (i) the sweeper, (ii) deoptimization, (iii) dependency
! //     invalidation, and (iv) being replaced by a different method version (tiered
! //     compilation). Not-entrant nmethods cannot be called by Java threads, but they
! //     can still be active on the stack. To ensure that active nmethods are not reclaimed,
  //     we have to wait until the next marking phase has completed. If a not-entrant
  //     nmethod was NOT marked as active, it can be converted to 'zombie' state. To safely
! //     remove the nmethod, all inline caches (IC) that point to the nmethod must be
  //     cleared. After that, the nmethod can be evicted from the code cache. Each nmethod's
  //     state change happens during separate sweeps. It may take at least 3 sweeps before an
  //     nmethod's space is freed.
  
  class NMethodSweeper : public AllStatic {