duke@435: /*
sla@5237:  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "code/codeCache.hpp"
coleenp@4037: #include "code/compiledIC.hpp"
coleenp@4037: #include "code/icBuffer.hpp"
stefank@2314: #include "code/nmethod.hpp"
stefank@2314: #include "compiler/compileBroker.hpp"
stefank@2314: #include "memory/resourceArea.hpp"
coleenp@4037: #include "oops/method.hpp"
stefank@2314: #include "runtime/atomic.hpp"
stefank@2314: #include "runtime/compilationPolicy.hpp"
stefank@2314: #include "runtime/mutexLocker.hpp"
stefank@2314: #include "runtime/os.hpp"
stefank@2314: #include "runtime/sweeper.hpp"
stefank@2314: #include "runtime/vm_operations.hpp"
sla@5237: #include "trace/tracing.hpp"
stefank@2314: #include "utilities/events.hpp"
stefank@2314: #include "utilities/xmlstream.hpp"
duke@435: 
never@2916: #ifdef ASSERT
never@2916: 
never@2916: #define SWEEP(nm) record_sweep(nm, __LINE__)
never@2916: // Sweeper logging code
never@2916: class SweeperRecord {
never@2916:  public:
never@2916:   int traversal;
never@2916:   int invocation;
never@2916:   int compile_id;
never@2916:   long traversal_mark;
never@2916:   int state;
never@2916:   const char* kind;
never@2916:   address vep;
never@2916:   address uep;
never@2916:   int line;
never@2916: 
never@2916:   void print() {
never@2916:       tty->print_cr("traversal = %d invocation = %d compile_id = %d %s uep = " PTR_FORMAT " vep = "
never@2916:                     PTR_FORMAT " state = %d traversal_mark %d line = %d",
never@2916:                     traversal,
never@2916:                     invocation,
never@2916:                     compile_id,
never@2916:                     kind == NULL ? "" : kind,
never@2916:                     uep,
never@2916:                     vep,
never@2916:                     state,
never@2916:                     traversal_mark,
never@2916:                     line);
never@2916:   }
never@2916: };
never@2916: 
never@2916: static int _sweep_index = 0;
never@2916: static SweeperRecord* _records = NULL;
never@2916: 
never@2916: void NMethodSweeper::report_events(int id, address entry) {
never@2916:   if (_records != NULL) {
never@2916:     for (int i = _sweep_index; i < SweeperLogEntries; i++) {
never@2916:       if (_records[i].uep == entry ||
never@2916:           _records[i].vep == entry ||
never@2916:           _records[i].compile_id == id) {
never@2916:         _records[i].print();
never@2916:       }
never@2916:     }
never@2916:     for (int i = 0; i < _sweep_index; i++) {
never@2916:       if (_records[i].uep == entry ||
never@2916:           _records[i].vep == entry ||
never@2916:           _records[i].compile_id == id) {
never@2916:         _records[i].print();
never@2916:       }
never@2916:     }
never@2916:   }
never@2916: }
never@2916: 
never@2916: void NMethodSweeper::report_events() {
never@2916:   if (_records != NULL) {
never@2916:     for (int i = _sweep_index; i < SweeperLogEntries; i++) {
never@2916:       // skip empty records
never@2916:       if (_records[i].vep == NULL) continue;
never@2916:       _records[i].print();
never@2916:     }
never@2916:     for (int i = 0; i < _sweep_index; i++) {
never@2916:       // skip empty records
never@2916:       if (_records[i].vep == NULL) continue;
never@2916:       _records[i].print();
never@2916:     }
never@2916:   }
never@2916: }
never@2916: 
never@2916: void NMethodSweeper::record_sweep(nmethod* nm, int line) {
never@2916:   if (_records != NULL) {
never@2916:     _records[_sweep_index].traversal = _traversals;
never@2916:     _records[_sweep_index].traversal_mark = nm->_stack_traversal_mark;
never@2916:     _records[_sweep_index].invocation = _invocations;
never@2916:     _records[_sweep_index].compile_id = nm->compile_id();
never@2916:     _records[_sweep_index].kind = nm->compile_kind();
never@2916:     _records[_sweep_index].state = nm->_state;
never@2916:     _records[_sweep_index].vep = nm->verified_entry_point();
never@2916:     _records[_sweep_index].uep = nm->entry_point();
never@2916:     _records[_sweep_index].line = line;
never@2916: 
never@2916:     _sweep_index = (_sweep_index + 1) % SweeperLogEntries;
never@2916:   }
never@2916: }
never@2916: #else
never@2916: #define SWEEP(nm)
never@2916: #endif
never@2916: 
anoll@5792: nmethod*  NMethodSweeper::_current         = NULL; // Current nmethod
anoll@5792: long      NMethodSweeper::_traversals      = 0;    // Nof. stack traversals performed
anoll@5792: int       NMethodSweeper::_seen            = 0;    // Nof. nmethods we have currently processed in current pass of CodeCache
anoll@5792: int       NMethodSweeper::_flushed_count   = 0;    // Nof. nmethods flushed in current sweep
anoll@5792: int       NMethodSweeper::_zombified_count = 0;    // Nof. nmethods made zombie in current sweep
anoll@5792: int       NMethodSweeper::_marked_count    = 0;    // Nof. nmethods marked for reclaim in current sweep
never@2916: 
anoll@5792: volatile int NMethodSweeper::_invocations   = 0; // Nof. invocations left until we are completed with this pass
never@1999: volatile int NMethodSweeper::_sweep_started = 0; // Whether a sweep is in progress.
duke@435: 
anoll@5792: jint      NMethodSweeper::_locked_seen               = 0;
duke@435: jint      NMethodSweeper::_not_entrant_seen_on_stack = 0;
anoll@5792: bool      NMethodSweeper::_request_mark_phase        = false;
duke@435: 
sla@5237: int       NMethodSweeper::_total_nof_methods_reclaimed = 0;
anoll@5792: jlong     NMethodSweeper::_total_time_sweeping         = 0;
anoll@5792: jlong     NMethodSweeper::_total_time_this_sweep       = 0;
anoll@5792: jlong     NMethodSweeper::_peak_sweep_time             = 0;
anoll@5792: jlong     NMethodSweeper::_peak_sweep_fraction_time    = 0;
anoll@5792: int       NMethodSweeper::_hotness_counter_reset_val   = 0;
anoll@5792: 
sla@5237: 
jrose@1424: class MarkActivationClosure: public CodeBlobClosure {
jrose@1424: public:
jrose@1424:   virtual void do_code_blob(CodeBlob* cb) {
anoll@5792:     if (cb->is_nmethod()) {
anoll@5792:       nmethod* nm = (nmethod*)cb;
anoll@5792:       nm->set_hotness_counter(NMethodSweeper::hotness_counter_reset_val());
anoll@5792:       // If we see an activation belonging to a non_entrant nmethod, we mark it.
anoll@5792:       if (nm->is_not_entrant()) {
anoll@5792:         nm->mark_as_seen_on_stack();
anoll@5792:       }
jrose@1424:     }
jrose@1424:   }
jrose@1424: };
jrose@1424: static MarkActivationClosure mark_activation_closure;
jrose@1424: 
anoll@5792: class SetHotnessClosure: public CodeBlobClosure {
anoll@5792: public:
anoll@5792:   virtual void do_code_blob(CodeBlob* cb) {
anoll@5792:     if (cb->is_nmethod()) {
anoll@5792:       nmethod* nm = (nmethod*)cb;
anoll@5792:       nm->set_hotness_counter(NMethodSweeper::hotness_counter_reset_val());
anoll@5792:     }
anoll@5792:   }
anoll@5792: };
anoll@5792: static SetHotnessClosure set_hotness_closure;
anoll@5792: 
anoll@5792: 
anoll@5792: int NMethodSweeper::hotness_counter_reset_val() {
anoll@5792:   if (_hotness_counter_reset_val == 0) {
anoll@5792:     _hotness_counter_reset_val = (ReservedCodeCacheSize < M) ? 1 : (ReservedCodeCacheSize / M) * 2;
anoll@5792:   }
anoll@5792:   return _hotness_counter_reset_val;
anoll@5792: }
neliasso@5038: bool NMethodSweeper::sweep_in_progress() {
neliasso@5038:   return (_current != NULL);
neliasso@5038: }
neliasso@5038: 
anoll@5792: // Scans the stacks of all Java threads and marks activations of not-entrant methods.
anoll@5792: // No need to synchronize access, since 'mark_active_nmethods' is always executed at a
anoll@5792: // safepoint.
anoll@5792: void NMethodSweeper::mark_active_nmethods() {
duke@435:   assert(SafepointSynchronize::is_at_safepoint(), "must be executed at a safepoint");
anoll@5792:   // If we do not want to reclaim not-entrant or zombie methods there is no need
anoll@5792:   // to scan stacks
anoll@5792:   if (!MethodFlushing) {
anoll@5792:     return;
anoll@5792:   }
duke@435: 
duke@435:   // Check for restart
duke@435:   assert(CodeCache::find_blob_unsafe(_current) == _current, "Sweeper nmethod cached state invalid");
anoll@5792:   if (!sweep_in_progress() && need_marking_phase()) {
duke@435:     _seen        = 0;
duke@435:     _invocations = NmethodSweepFraction;
never@1893:     _current     = CodeCache::first_nmethod();
duke@435:     _traversals  += 1;
sla@5237:     _total_time_this_sweep = 0;
sla@5237: 
duke@435:     if (PrintMethodFlushing) {
duke@435:       tty->print_cr("### Sweep: stack traversal %d", _traversals);
duke@435:     }
jrose@1424:     Threads::nmethods_do(&mark_activation_closure);
duke@435: 
duke@435:     // reset the flags since we started a scan from the beginning.
anoll@5792:     reset_nmethod_marking();
duke@435:     _locked_seen = 0;
duke@435:     _not_entrant_seen_on_stack = 0;
anoll@5792:   } else {
anoll@5792:     // Only set hotness counter
anoll@5792:     Threads::nmethods_do(&set_hotness_closure);
duke@435:   }
duke@435: 
anoll@5792:   OrderAccess::storestore();
duke@435: }
duke@435: 
never@1893: void NMethodSweeper::possibly_sweep() {
never@1999:   assert(JavaThread::current()->thread_state() == _thread_in_vm, "must run in vm mode");
anoll@5792:   if (!MethodFlushing || !sweep_in_progress()) {
anoll@5792:     return;
anoll@5792:   }
never@1893: 
never@1893:   if (_invocations > 0) {
never@1893:     // Only one thread at a time will sweep
never@1893:     jint old = Atomic::cmpxchg( 1, &_sweep_started, 0 );
never@1893:     if (old != 0) {
never@1893:       return;
never@1893:     }
never@2916: #ifdef ASSERT
never@2916:     if (LogSweeper && _records == NULL) {
never@2916:       // Create the ring buffer for the logging code
zgu@3900:       _records = NEW_C_HEAP_ARRAY(SweeperRecord, SweeperLogEntries, mtGC);
never@2916:       memset(_records, 0, sizeof(SweeperRecord) * SweeperLogEntries);
never@2916:     }
never@2916: #endif
never@1999:     if (_invocations > 0) {
never@1999:       sweep_code_cache();
never@1999:       _invocations--;
never@1999:     }
never@1999:     _sweep_started = 0;
never@1893:   }
never@1893: }
never@1893: 
never@1893: void NMethodSweeper::sweep_code_cache() {
sla@5237: 
sla@5237:   jlong sweep_start_counter = os::elapsed_counter();
sla@5237: 
sla@5237:   _flushed_count   = 0;
sla@5237:   _zombified_count = 0;
sla@5237:   _marked_count    = 0;
sla@5237: 
never@1893:   if (PrintMethodFlushing && Verbose) {
never@1999:     tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_nmethods(), _invocations);
never@1893:   }
never@1893: 
neliasso@5038:   if (!CompileBroker::should_compile_new_jobs()) {
neliasso@5038:     // If we have turned off compilations we might as well do full sweeps
neliasso@5038:     // in order to reach the clean state faster. Otherwise the sleeping compiler
anoll@5792:     // threads will slow down sweeping.
neliasso@5038:     _invocations = 1;
neliasso@5038:   }
neliasso@5038: 
never@1999:   // We want to visit all nmethods after NmethodSweepFraction
never@1999:   // invocations so divide the remaining number of nmethods by the
never@1999:   // remaining number of invocations.  This is only an estimate since
never@1999:   // the number of nmethods changes during the sweep so the final
never@1999:   // stage must iterate until it there are no more nmethods.
never@1999:   int todo = (CodeCache::nof_nmethods() - _seen) / _invocations;
anoll@5734:   int swept_count = 0;
never@1893: 
anoll@5792: 
never@1893:   assert(!SafepointSynchronize::is_at_safepoint(), "should not be in safepoint when we get here");
never@1893:   assert(!CodeCache_lock->owned_by_self(), "just checking");
never@1893: 
anoll@5792:   int freed_memory = 0;
never@1893:   {
never@1893:     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
never@1893: 
never@1999:     // The last invocation iterates until there are no more nmethods
never@1999:     for (int i = 0; (i < todo || _invocations == 1) && _current != NULL; i++) {
anoll@5734:       swept_count++;
iveresov@3572:       if (SafepointSynchronize::is_synchronizing()) { // Safepoint request
iveresov@3572:         if (PrintMethodFlushing && Verbose) {
iveresov@3572:           tty->print_cr("### Sweep at %d out of %d, invocation: %d, yielding to safepoint", _seen, CodeCache::nof_nmethods(), _invocations);
iveresov@3572:         }
iveresov@3572:         MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
never@1893: 
iveresov@3572:         assert(Thread::current()->is_Java_thread(), "should be java thread");
iveresov@3572:         JavaThread* thread = (JavaThread*)Thread::current();
iveresov@3572:         ThreadBlockInVM tbivm(thread);
iveresov@3572:         thread->java_suspend_self();
iveresov@3572:       }
never@1999:       // Since we will give up the CodeCache_lock, always skip ahead
never@1999:       // to the next nmethod.  Other blobs can be deleted by other
never@1999:       // threads but nmethods are only reclaimed by the sweeper.
never@1970:       nmethod* next = CodeCache::next_nmethod(_current);
never@1893: 
never@1893:       // Now ready to process nmethod and give up CodeCache_lock
never@1893:       {
never@1893:         MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
anoll@5792:         freed_memory += process_nmethod(_current);
never@1893:       }
never@1893:       _seen++;
never@1893:       _current = next;
never@1893:     }
never@1893:   }
never@1893: 
never@1999:   assert(_invocations > 1 || _current == NULL, "must have scanned the whole cache");
never@1999: 
anoll@5792:   if (!sweep_in_progress() && !need_marking_phase() && (_locked_seen || _not_entrant_seen_on_stack)) {
never@1893:     // we've completed a scan without making progress but there were
never@1893:     // nmethods we were unable to process either because they were
anoll@5792:     // locked or were still on stack. We don't have to aggressively
anoll@5792:     // clean them up so just stop scanning. We could scan once more
never@1893:     // but that complicates the control logic and it's unlikely to
never@1893:     // matter much.
never@1893:     if (PrintMethodFlushing) {
never@1893:       tty->print_cr("### Couldn't make progress on some nmethods so stopping sweep");
never@1893:     }
never@1893:   }
never@1893: 
sla@5237:   jlong sweep_end_counter = os::elapsed_counter();
sla@5237:   jlong sweep_time = sweep_end_counter - sweep_start_counter;
sla@5237:   _total_time_sweeping  += sweep_time;
sla@5237:   _total_time_this_sweep += sweep_time;
sla@5237:   _peak_sweep_fraction_time = MAX2(sweep_time, _peak_sweep_fraction_time);
sla@5237:   _total_nof_methods_reclaimed += _flushed_count;
sla@5237: 
sla@5237:   EventSweepCodeCache event(UNTIMED);
sla@5237:   if (event.should_commit()) {
sla@5237:     event.set_starttime(sweep_start_counter);
sla@5237:     event.set_endtime(sweep_end_counter);
sla@5237:     event.set_sweepIndex(_traversals);
sla@5237:     event.set_sweepFractionIndex(NmethodSweepFraction - _invocations + 1);
anoll@5734:     event.set_sweptCount(swept_count);
sla@5237:     event.set_flushedCount(_flushed_count);
sla@5237:     event.set_markedCount(_marked_count);
sla@5237:     event.set_zombifiedCount(_zombified_count);
sla@5237:     event.commit();
sla@5237:   }
sla@5237: 
never@1893: #ifdef ASSERT
never@1893:   if(PrintMethodFlushing) {
sla@5237:     tty->print_cr("### sweeper:      sweep time(%d): " INT64_FORMAT, _invocations, (jlong)sweep_time);
never@1893:   }
never@1893: #endif
never@1999: 
never@1999:   if (_invocations == 1) {
sla@5237:     _peak_sweep_time = MAX2(_peak_sweep_time, _total_time_this_sweep);
never@1999:     log_sweep("finished");
never@1999:   }
neliasso@5038: 
anoll@5792:   // Sweeper is the only case where memory is released, check here if it
anoll@5792:   // is time to restart the compiler. Only checking if there is a certain
anoll@5792:   // amount of free memory in the code cache might lead to re-enabling
anoll@5792:   // compilation although no memory has been released. For example, there are
anoll@5792:   // cases when compilation was disabled although there is 4MB (or more) free
anoll@5792:   // memory in the code cache. The reason is code cache fragmentation. Therefore,
anoll@5792:   // it only makes sense to re-enable compilation if we have actually freed memory.
anoll@5792:   // Note that typically several kB are released for sweeping 16MB of the code
anoll@5792:   // cache. As a result, 'freed_memory' > 0 to restart the compiler.
anoll@5792:   if (UseCodeCacheFlushing && (!CompileBroker::should_compile_new_jobs() && (freed_memory > 0))) {
neliasso@5038:     CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
neliasso@5038:     log_sweep("restart_compiler");
neliasso@5038:   }
never@1893: }
never@1893: 
never@2916: class NMethodMarker: public StackObj {
never@2916:  private:
never@2916:   CompilerThread* _thread;
never@2916:  public:
never@2916:   NMethodMarker(nmethod* nm) {
never@2916:     _thread = CompilerThread::current();
coleenp@4037:     if (!nm->is_zombie() && !nm->is_unloaded()) {
coleenp@4037:       // Only expose live nmethods for scanning
anoll@5792:       _thread->set_scanned_nmethod(nm);
anoll@5792:     }
coleenp@4037:   }
never@2916:   ~NMethodMarker() {
never@2916:     _thread->set_scanned_nmethod(NULL);
never@2916:   }
never@2916: };
never@2916: 
coleenp@4037: void NMethodSweeper::release_nmethod(nmethod *nm) {
coleenp@4037:   // Clean up any CompiledICHolders
coleenp@4037:   {
coleenp@4037:     ResourceMark rm;
coleenp@4037:     MutexLocker ml_patch(CompiledIC_lock);
coleenp@4037:     RelocIterator iter(nm);
coleenp@4037:     while (iter.next()) {
coleenp@4037:       if (iter.type() == relocInfo::virtual_call_type) {
coleenp@4037:         CompiledIC::cleanup_call_site(iter.virtual_call_reloc());
coleenp@4037:       }
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037: 
coleenp@4037:   MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
coleenp@4037:   nm->flush();
coleenp@4037: }
duke@435: 
anoll@5792: int NMethodSweeper::process_nmethod(nmethod *nm) {
never@1893:   assert(!CodeCache_lock->owned_by_self(), "just checking");
never@1893: 
anoll@5792:   int freed_memory = 0;
never@2916:   // Make sure this nmethod doesn't get unloaded during the scan,
anoll@5792:   // since safepoints may happen during acquired below locks.
never@2916:   NMethodMarker nmm(nm);
never@2916:   SWEEP(nm);
never@2916: 
duke@435:   // Skip methods that are currently referenced by the VM
duke@435:   if (nm->is_locked_by_vm()) {
duke@435:     // But still remember to clean-up inline caches for alive nmethods
duke@435:     if (nm->is_alive()) {
anoll@5792:       // Clean inline caches that point to zombie/non-entrant methods
never@1893:       MutexLocker cl(CompiledIC_lock);
duke@435:       nm->cleanup_inline_caches();
never@2916:       SWEEP(nm);
duke@435:     } else {
duke@435:       _locked_seen++;
never@2916:       SWEEP(nm);
duke@435:     }
anoll@5792:     return freed_memory;
duke@435:   }
duke@435: 
duke@435:   if (nm->is_zombie()) {
anoll@5792:     // If it is the first time we see nmethod then we mark it. Otherwise,
anoll@5792:     // we reclaim it. When we have seen a zombie method twice, we know that
never@1999:     // there are no inline caches that refer to it.
duke@435:     if (nm->is_marked_for_reclamation()) {
duke@435:       assert(!nm->is_locked_by_vm(), "must not flush locked nmethods");
ysr@1376:       if (PrintMethodFlushing && Verbose) {
kvn@1637:         tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (marked for reclamation) being flushed", nm->compile_id(), nm);
ysr@1376:       }
anoll@5792:       freed_memory = nm->total_size();
coleenp@4037:       release_nmethod(nm);
sla@5237:       _flushed_count++;
duke@435:     } else {
ysr@1376:       if (PrintMethodFlushing && Verbose) {
kvn@1637:         tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (zombie) being marked for reclamation", nm->compile_id(), nm);
ysr@1376:       }
duke@435:       nm->mark_for_reclamation();
anoll@5792:       request_nmethod_marking();
sla@5237:       _marked_count++;
never@2916:       SWEEP(nm);
duke@435:     }
duke@435:   } else if (nm->is_not_entrant()) {
anoll@5792:     // If there are no current activations of this method on the
duke@435:     // stack we can safely convert it to a zombie method
duke@435:     if (nm->can_not_entrant_be_converted()) {
ysr@1376:       if (PrintMethodFlushing && Verbose) {
kvn@1637:         tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (not entrant) being made zombie", nm->compile_id(), nm);
ysr@1376:       }
duke@435:       nm->make_zombie();
anoll@5792:       request_nmethod_marking();
sla@5237:       _zombified_count++;
never@2916:       SWEEP(nm);
duke@435:     } else {
duke@435:       // Still alive, clean up its inline caches
never@1893:       MutexLocker cl(CompiledIC_lock);
duke@435:       nm->cleanup_inline_caches();
duke@435:       // we coudn't transition this nmethod so don't immediately
duke@435:       // request a rescan.  If this method stays on the stack for a
never@1893:       // long time we don't want to keep rescanning the code cache.
duke@435:       _not_entrant_seen_on_stack++;
never@2916:       SWEEP(nm);
duke@435:     }
duke@435:   } else if (nm->is_unloaded()) {
duke@435:     // Unloaded code, just make it a zombie
anoll@5792:     if (PrintMethodFlushing && Verbose) {
kvn@1637:       tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (unloaded) being made zombie", nm->compile_id(), nm);
anoll@5792:     }
ysr@1376:     if (nm->is_osr_method()) {
coleenp@4037:       SWEEP(nm);
duke@435:       // No inline caches will ever point to osr methods, so we can just remove it
anoll@5792:       freed_memory = nm->total_size();
coleenp@4037:       release_nmethod(nm);
sla@5237:       _flushed_count++;
duke@435:     } else {
duke@435:       nm->make_zombie();
anoll@5792:       request_nmethod_marking();
sla@5237:       _zombified_count++;
never@2916:       SWEEP(nm);
duke@435:     }
duke@435:   } else {
kvn@1637:     if (UseCodeCacheFlushing) {
anoll@5792:       if (!nm->is_locked_by_vm() && !nm->is_osr_method() && !nm->is_native_method()) {
anoll@5792:         // Do not make native methods and OSR-methods not-entrant
anoll@5792:         nm->dec_hotness_counter();
anoll@5792:         // Get the initial value of the hotness counter. This value depends on the
anoll@5792:         // ReservedCodeCacheSize
anoll@5792:         int reset_val = hotness_counter_reset_val();
anoll@5792:         int time_since_reset = reset_val - nm->hotness_counter();
anoll@5792:         double threshold = -reset_val + (CodeCache::reverse_free_ratio() * NmethodSweepActivity);
anoll@5792:         // The less free space in the code cache we have - the bigger reverse_free_ratio() is.
anoll@5792:         // I.e., 'threshold' increases with lower available space in the code cache and a higher
anoll@5792:         // NmethodSweepActivity. If the current hotness counter - which decreases from its initial
anoll@5792:         // value until it is reset by stack walking - is smaller than the computed threshold, the
anoll@5792:         // corresponding nmethod is considered for removal.
anoll@5792:         if ((NmethodSweepActivity > 0) && (nm->hotness_counter() < threshold) && (time_since_reset > 10)) {
anoll@5792:           // A method is marked as not-entrant if the method is
anoll@5792:           // 1) 'old enough': nm->hotness_counter() < threshold
anoll@5792:           // 2) The method was in_use for a minimum amount of time: (time_since_reset > 10)
anoll@5792:           //    The second condition is necessary if we are dealing with very small code cache
anoll@5792:           //    sizes (e.g., <10m) and the code cache size is too small to hold all hot methods.
anoll@5792:           //    The second condition ensures that methods are not immediately made not-entrant
anoll@5792:           //    after compilation.
anoll@5792:           nm->make_not_entrant();
anoll@5792:           request_nmethod_marking();
anoll@5792:         }
kvn@1637:       }
kvn@1637:     }
anoll@5792:     // Clean-up all inline caches that point to zombie/non-reentrant methods
never@1893:     MutexLocker cl(CompiledIC_lock);
duke@435:     nm->cleanup_inline_caches();
never@2916:     SWEEP(nm);
duke@435:   }
anoll@5792:   return freed_memory;
duke@435: }
kvn@1637: 
never@1999: // Print out some state information about the current sweep and the
never@1999: // state of the code cache if it's requested.
never@1999: void NMethodSweeper::log_sweep(const char* msg, const char* format, ...) {
never@1999:   if (PrintMethodFlushing) {
iveresov@2764:     stringStream s;
iveresov@2764:     // Dump code cache state into a buffer before locking the tty,
iveresov@2764:     // because log_state() will use locks causing lock conflicts.
iveresov@2764:     CodeCache::log_state(&s);
iveresov@2764: 
never@1999:     ttyLocker ttyl;
never@1999:     tty->print("### sweeper: %s ", msg);
never@1999:     if (format != NULL) {
never@1999:       va_list ap;
never@1999:       va_start(ap, format);
never@1999:       tty->vprint(format, ap);
never@1999:       va_end(ap);
never@1999:     }
iveresov@2764:     tty->print_cr(s.as_string());
never@1999:   }
never@1999: 
never@1999:   if (LogCompilation && (xtty != NULL)) {
iveresov@2764:     stringStream s;
iveresov@2764:     // Dump code cache state into a buffer before locking the tty,
iveresov@2764:     // because log_state() will use locks causing lock conflicts.
iveresov@2764:     CodeCache::log_state(&s);
iveresov@2764: 
never@1999:     ttyLocker ttyl;
never@2001:     xtty->begin_elem("sweeper state='%s' traversals='" INTX_FORMAT "' ", msg, (intx)traversal_count());
never@1999:     if (format != NULL) {
never@1999:       va_list ap;
never@1999:       va_start(ap, format);
never@1999:       xtty->vprint(format, ap);
never@1999:       va_end(ap);
never@1999:     }
iveresov@2764:     xtty->print(s.as_string());
never@1999:     xtty->stamp();
never@1999:     xtty->end_elem();
never@1999:   }
never@1999: }