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: 
never@2916: 
duke@435: long      NMethodSweeper::_traversals = 0;   // No. of stack traversals performed
never@1970: nmethod*  NMethodSweeper::_current = NULL;   // Current nmethod
never@1999: int       NMethodSweeper::_seen = 0 ;        // No. of nmethods we have currently processed in current pass of CodeCache
sla@5237: int       NMethodSweeper::_flushed_count = 0;   // Nof. nmethods flushed in current sweep
sla@5237: int       NMethodSweeper::_zombified_count = 0; // Nof. nmethods made zombie in current sweep
sla@5237: int       NMethodSweeper::_marked_count = 0;    // Nof. nmethods marked for reclaim in current sweep
never@1999: 
never@1999: volatile int NMethodSweeper::_invocations = 0;   // No. of 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: 
duke@435: jint      NMethodSweeper::_locked_seen = 0;
duke@435: jint      NMethodSweeper::_not_entrant_seen_on_stack = 0;
neliasso@5038: bool      NMethodSweeper::_resweep = false;
neliasso@5038: jint      NMethodSweeper::_flush_token = 0;
neliasso@5038: jlong     NMethodSweeper::_last_full_flush_time = 0;
neliasso@5038: int       NMethodSweeper::_highest_marked = 0;
neliasso@5038: int       NMethodSweeper::_dead_compile_ids = 0;
neliasso@5038: long      NMethodSweeper::_last_flush_traversal_id = 0;
duke@435: 
sla@5237: int       NMethodSweeper::_number_of_flushes = 0; // Total of full traversals caused by full cache
sla@5237: int       NMethodSweeper::_total_nof_methods_reclaimed = 0;
sla@5237: jlong     NMethodSweeper::_total_time_sweeping = 0;
sla@5237: jlong     NMethodSweeper::_total_time_this_sweep = 0;
sla@5237: jlong     NMethodSweeper::_peak_sweep_time = 0;
sla@5237: jlong     NMethodSweeper::_peak_sweep_fraction_time = 0;
sla@5237: jlong     NMethodSweeper::_total_disconnect_time = 0;
sla@5237: jlong     NMethodSweeper::_peak_disconnect_time = 0;
sla@5237: 
jrose@1424: class MarkActivationClosure: public CodeBlobClosure {
jrose@1424: public:
jrose@1424:   virtual void do_code_blob(CodeBlob* cb) {
jrose@1424:     // If we see an activation belonging to a non_entrant nmethod, we mark it.
jrose@1424:     if (cb->is_nmethod() && ((nmethod*)cb)->is_not_entrant()) {
jrose@1424:       ((nmethod*)cb)->mark_as_seen_on_stack();
jrose@1424:     }
jrose@1424:   }
jrose@1424: };
jrose@1424: static MarkActivationClosure mark_activation_closure;
jrose@1424: 
neliasso@5038: bool NMethodSweeper::sweep_in_progress() {
neliasso@5038:   return (_current != NULL);
neliasso@5038: }
neliasso@5038: 
never@1893: void NMethodSweeper::scan_stacks() {
duke@435:   assert(SafepointSynchronize::is_at_safepoint(), "must be executed at a safepoint");
duke@435:   if (!MethodFlushing) return;
duke@435: 
duke@435:   // No need to synchronize access, since this is always executed at a
neliasso@5038:   // safepoint.
duke@435: 
duke@435:   // Make sure CompiledIC_lock in unlocked, since we might update some
duke@435:   // inline caches. If it is, we just bail-out and try later.
duke@435:   if (CompiledIC_lock->is_locked() || Patching_lock->is_locked()) return;
duke@435: 
duke@435:   // Check for restart
duke@435:   assert(CodeCache::find_blob_unsafe(_current) == _current, "Sweeper nmethod cached state invalid");
neliasso@5038:   if (!sweep_in_progress() && _resweep) {
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.
neliasso@5038:     _resweep = false;
duke@435:     _locked_seen = 0;
duke@435:     _not_entrant_seen_on_stack = 0;
duke@435:   }
duke@435: 
kvn@1637:   if (UseCodeCacheFlushing) {
neliasso@5038:     // only allow new flushes after the interval is complete.
neliasso@5038:     jlong now           = os::javaTimeMillis();
neliasso@5038:     jlong max_interval  = (jlong)MinCodeCacheFlushingInterval * (jlong)1000;
neliasso@5038:     jlong curr_interval = now - _last_full_flush_time;
neliasso@5038:     if (curr_interval > max_interval) {
neliasso@5038:       _flush_token = 0;
kvn@1637:     }
kvn@1637: 
neliasso@5038:     if (!CodeCache::needs_flushing() && !CompileBroker::should_compile_new_jobs()) {
neliasso@5038:       CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
neliasso@5038:       log_sweep("restart_compiler");
kvn@1637:     }
kvn@1637:   }
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");
neliasso@5038:   if (!MethodFlushing || !sweep_in_progress()) return;
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
neliasso@5038:     // threads will slow down sweeping. After a few iterations the cache
neliasso@5038:     // will be clean and sweeping stops (_resweep will not be set)
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;
never@1893: 
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: 
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++) {
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);
never@1970:         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: 
neliasso@5038:   if (!sweep_in_progress() && !_resweep && (_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
never@1893:     // locked or were still on stack.  We don't have to aggresively
never@1893:     // 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);
sla@5237:     event.set_sweptCount(todo);
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: 
neliasso@5038:   // Sweeper is the only case where memory is released,
neliasso@5038:   // check here if it is time to restart the compiler.
neliasso@5038:   if (UseCodeCacheFlushing && !CompileBroker::should_compile_new_jobs() && !CodeCache::needs_flushing()) {
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
never@2916:     _thread->set_scanned_nmethod(nm);
never@2916:   }
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: 
duke@435: void NMethodSweeper::process_nmethod(nmethod *nm) {
never@1893:   assert(!CodeCache_lock->owned_by_self(), "just checking");
never@1893: 
never@2916:   // Make sure this nmethod doesn't get unloaded during the scan,
never@2916:   // since the locks acquired below might safepoint.
never@2916:   NMethodMarker nmm(nm);
never@2916: 
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()) {
duke@435:       // Clean-up all inline caches that points to zombie/non-reentrant 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:     }
duke@435:     return;
duke@435:   }
duke@435: 
duke@435:   if (nm->is_zombie()) {
duke@435:     // If it is first time, we see nmethod then we mark it. Otherwise,
duke@435:     // we reclame 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:       }
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();
neliasso@5038:       _resweep = true;
sla@5237:       _marked_count++;
never@2916:       SWEEP(nm);
duke@435:     }
duke@435:   } else if (nm->is_not_entrant()) {
duke@435:     // If there is 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();
neliasso@5038:       _resweep = true;
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
ysr@1376:     if (PrintMethodFlushing && Verbose)
kvn@1637:       tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (unloaded) being made zombie", nm->compile_id(), nm);
sla@5237: 
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
coleenp@4037:       release_nmethod(nm);
sla@5237:       _flushed_count++;
duke@435:     } else {
duke@435:       nm->make_zombie();
neliasso@5038:       _resweep = true;
sla@5237:       _zombified_count++;
never@2916:       SWEEP(nm);
duke@435:     }
duke@435:   } else {
duke@435:     assert(nm->is_alive(), "should be alive");
kvn@1637: 
kvn@1637:     if (UseCodeCacheFlushing) {
neliasso@5038:       if (nm->is_speculatively_disconnected() && !nm->is_locked_by_vm() && !nm->is_osr_method() &&
neliasso@5038:           (_traversals > _last_flush_traversal_id + 2) && (nm->compile_id() < _highest_marked)) {
kvn@1637:         // This method has not been called since the forced cleanup happened
kvn@1637:         nm->make_not_entrant();
kvn@1637:       }
kvn@1637:     }
kvn@1637: 
duke@435:     // Clean-up all inline caches that points to zombie/non-reentrant methods
never@1893:     MutexLocker cl(CompiledIC_lock);
duke@435:     nm->cleanup_inline_caches();
never@2916:     SWEEP(nm);
duke@435:   }
duke@435: }
kvn@1637: 
kvn@1637: // Code cache unloading: when compilers notice the code cache is getting full,
kvn@1637: // they will call a vm op that comes here. This code attempts to speculatively
kvn@1637: // unload the oldest half of the nmethods (based on the compile job id) by
kvn@1637: // saving the old code in a list in the CodeCache. Then
never@1893: // execution resumes. If a method so marked is not called by the second sweeper
never@1893: // stack traversal after the current one, the nmethod will be marked non-entrant and
coleenp@4037: // got rid of by normal sweeping. If the method is called, the Method*'s
coleenp@4037: // _code field is restored and the Method*/nmethod
kvn@1637: // go back to their normal state.
kvn@1637: void NMethodSweeper::handle_full_code_cache(bool is_full) {
neliasso@5038: 
neliasso@5038:   if (is_full) {
neliasso@5038:     // Since code cache is full, immediately stop new compiles
neliasso@5038:     if (CompileBroker::set_should_compile_new_jobs(CompileBroker::stop_compilation)) {
neliasso@5038:       log_sweep("disable_compiler");
kvn@1637:     }
kvn@1637:   }
kvn@1637: 
neliasso@5038:   // Make sure only one thread can flush
neliasso@5038:   // The token is reset after CodeCacheMinimumFlushInterval in scan stacks,
neliasso@5038:   // no need to check the timeout here.
neliasso@5038:   jint old = Atomic::cmpxchg( 1, &_flush_token, 0 );
neliasso@5038:   if (old != 0) {
neliasso@5038:     return;
kvn@1637:   }
kvn@1637: 
kvn@1637:   VM_HandleFullCodeCache op(is_full);
kvn@1637:   VMThread::execute(&op);
kvn@1637: 
neliasso@5038:   // resweep again as soon as possible
neliasso@5038:   _resweep = true;
kvn@1637: }
kvn@1637: 
kvn@1637: void NMethodSweeper::speculative_disconnect_nmethods(bool is_full) {
kvn@1637:   // If there was a race in detecting full code cache, only run
kvn@1637:   // one vm op for it or keep the compiler shut off
kvn@1637: 
sla@5237:   jlong disconnect_start_counter = os::elapsed_counter();
kvn@1637: 
neliasso@5038:   // Traverse the code cache trying to dump the oldest nmethods
neliasso@5038:   int curr_max_comp_id = CompileBroker::get_compilation_id();
neliasso@5038:   int flush_target = ((curr_max_comp_id - _dead_compile_ids) / CodeCacheFlushingFraction) + _dead_compile_ids;
kvn@1637: 
never@1999:   log_sweep("start_cleaning");
kvn@1637: 
kvn@1637:   nmethod* nm = CodeCache::alive_nmethod(CodeCache::first());
kvn@1637:   jint disconnected = 0;
kvn@1637:   jint made_not_entrant  = 0;
neliasso@5038:   jint nmethod_count = 0;
neliasso@5038: 
kvn@1637:   while ((nm != NULL)){
neliasso@5038:     int curr_comp_id = nm->compile_id();
kvn@1637: 
kvn@1637:     // OSR methods cannot be flushed like this. Also, don't flush native methods
kvn@1637:     // since they are part of the JDK in most cases
neliasso@5038:     if (!nm->is_osr_method() && !nm->is_locked_by_vm() && !nm->is_native_method()) {
kvn@1637: 
neliasso@5038:       // only count methods that can be speculatively disconnected
neliasso@5038:       nmethod_count++;
kvn@1637: 
neliasso@5038:       if (nm->is_in_use() && (curr_comp_id < flush_target)) {
neliasso@5038:         if ((nm->method()->code() == nm)) {
neliasso@5038:           // This method has not been previously considered for
neliasso@5038:           // unloading or it was restored already
neliasso@5038:           CodeCache::speculatively_disconnect(nm);
neliasso@5038:           disconnected++;
neliasso@5038:         } else if (nm->is_speculatively_disconnected()) {
neliasso@5038:           // This method was previously considered for preemptive unloading and was not called since then
neliasso@5038:           CompilationPolicy::policy()->delay_compilation(nm->method());
neliasso@5038:           nm->make_not_entrant();
neliasso@5038:           made_not_entrant++;
neliasso@5038:         }
neliasso@5038: 
neliasso@5038:         if (curr_comp_id > _highest_marked) {
neliasso@5038:           _highest_marked = curr_comp_id;
neliasso@5038:         }
kvn@1637:       }
kvn@1637:     }
kvn@1637:     nm = CodeCache::alive_nmethod(CodeCache::next(nm));
kvn@1637:   }
kvn@1637: 
neliasso@5038:   // remember how many compile_ids wheren't seen last flush.
neliasso@5038:   _dead_compile_ids = curr_max_comp_id - nmethod_count;
neliasso@5038: 
never@1999:   log_sweep("stop_cleaning",
never@1999:                        "disconnected='" UINT32_FORMAT "' made_not_entrant='" UINT32_FORMAT "'",
never@1999:                        disconnected, made_not_entrant);
kvn@1637: 
never@1893:   // Shut off compiler. Sweeper will start over with a new stack scan and
never@1893:   // traversal cycle and turn it back on if it clears enough space.
neliasso@5038:   if (is_full) {
neliasso@5038:     _last_full_flush_time = os::javaTimeMillis();
kvn@1637:   }
kvn@1637: 
sla@5237:   jlong disconnect_end_counter = os::elapsed_counter();
sla@5237:   jlong disconnect_time = disconnect_end_counter - disconnect_start_counter;
sla@5237:   _total_disconnect_time += disconnect_time;
sla@5237:   _peak_disconnect_time = MAX2(disconnect_time, _peak_disconnect_time);
sla@5237: 
sla@5237:   EventCleanCodeCache event(UNTIMED);
sla@5237:   if (event.should_commit()) {
sla@5237:     event.set_starttime(disconnect_start_counter);
sla@5237:     event.set_endtime(disconnect_end_counter);
sla@5237:     event.set_disconnectedCount(disconnected);
sla@5237:     event.set_madeNonEntrantCount(made_not_entrant);
sla@5237:     event.commit();
sla@5237:   }
sla@5237:   _number_of_flushes++;
sla@5237: 
kvn@1637:   // After two more traversals the sweeper will get rid of unrestored nmethods
neliasso@5038:   _last_flush_traversal_id = _traversals;
neliasso@5038:   _resweep = true;
kvn@1637: #ifdef ASSERT
sla@5237: 
kvn@1637:   if(PrintMethodFlushing && Verbose) {
sla@5237:     tty->print_cr("### sweeper: unload time: " INT64_FORMAT, (jlong)disconnect_time);
kvn@1637:   }
kvn@1637: #endif
kvn@1637: }
never@1999: 
never@1999: 
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: }