graal-compiler: src/share/vm/runtime/sweeper.cpp comparison

comparison src/share/vm/runtime/sweeper.cpp @ 10206:0cfa93c2fcc4

8012547: Code cache flushing can get stuck reclaming of memory Summary: Keep sweeping regardless of if we are flushing Reviewed-by: kvn, twisti

author	neliasso
date	Mon, 29 Apr 2013 13:20:19 +0200
parents	da91efe96a93
children	f2110083203d

comparison

equal deleted inserted replaced

-:62b683108582
+:0cfa93c2fcc4
 volatile int NMethodSweeper::_invocations = 0;   // No. of invocations left until we are completed with this pass
 volatile int NMethodSweeper::_sweep_started = 0; // Whether a sweep is in progress.
 jint      NMethodSweeper::_locked_seen = 0;
 jint      NMethodSweeper::_not_entrant_seen_on_stack = 0;
-bool      NMethodSweeper::_rescan = false;
+bool      NMethodSweeper::_resweep = false;
-bool      NMethodSweeper::_do_sweep = false;
+jint      NMethodSweeper::_flush_token = 0;
-bool      NMethodSweeper::_was_full = false;
+jlong     NMethodSweeper::_last_full_flush_time = 0;
-jint      NMethodSweeper::_advise_to_sweep = 0;
+int       NMethodSweeper::_highest_marked = 0;
-jlong     NMethodSweeper::_last_was_full = 0;
+int       NMethodSweeper::_dead_compile_ids = 0;
-uint      NMethodSweeper::_highest_marked = 0;
+long      NMethodSweeper::_last_flush_traversal_id = 0;
-long      NMethodSweeper::_was_full_traversal = 0;
 class MarkActivationClosure: public CodeBlobClosure {
 public:
 virtual void do_code_blob(CodeBlob* cb) {
 // If we see an activation belonging to a non_entrant nmethod, we mark it.
 }
 }
 };
 static MarkActivationClosure mark_activation_closure;
+bool NMethodSweeper::sweep_in_progress() {
+return (_current != NULL);
+}
 void NMethodSweeper::scan_stacks() {
 assert(SafepointSynchronize::is_at_safepoint(), "must be executed at a safepoint");
 if (!MethodFlushing) return;
-_do_sweep = true;
 // No need to synchronize access, since this is always executed at a
-// safepoint.  If we aren't in the middle of scan and a rescan
+// safepoint.
-// hasn't been requested then just return. If UseCodeCacheFlushing is on and
-// code cache flushing is in progress, don't skip sweeping to help make progress
-// clearing space in the code cache.
-if ((_current == NULL && !_rescan) && !(UseCodeCacheFlushing && !CompileBroker::should_compile_new_jobs())) {
-_do_sweep = false;
-return;
-}
 // Make sure CompiledIC_lock in unlocked, since we might update some
 // inline caches. If it is, we just bail-out and try later.
 if (CompiledIC_lock->is_locked() || Patching_lock->is_locked()) return;
 // Check for restart
 assert(CodeCache::find_blob_unsafe(_current) == _current, "Sweeper nmethod cached state invalid");
-if (_current == NULL) {
+if (!sweep_in_progress() && _resweep) {
 _seen        = 0;
 _invocations = NmethodSweepFraction;
 _current     = CodeCache::first_nmethod();
 _traversals  += 1;
 if (PrintMethodFlushing) {
 tty->print_cr("### Sweep: stack traversal %d", _traversals);
 }
 Threads::nmethods_do(&mark_activation_closure);
 // reset the flags since we started a scan from the beginning.
-_rescan = false;
+_resweep = false;
 _locked_seen = 0;
 _not_entrant_seen_on_stack = 0;
 }
 if (UseCodeCacheFlushing) {
-if (!CodeCache::needs_flushing()) {
+// only allow new flushes after the interval is complete.
-// scan_stacks() runs during a safepoint, no race with setters
+jlong now           = os::javaTimeMillis();
-_advise_to_sweep = 0;
+jlong max_interval  = (jlong)MinCodeCacheFlushingInterval * (jlong)1000;
-}
+jlong curr_interval = now - _last_full_flush_time;
+if (curr_interval > max_interval) {
-if (was_full()) {
+_flush_token = 0;
-// There was some progress so attempt to restart the compiler
+}
-jlong now           = os::javaTimeMillis();
-jlong max_interval  = (jlong)MinCodeCacheFlushingInterval * (jlong)1000;
+if (!CodeCache::needs_flushing() && !CompileBroker::should_compile_new_jobs()) {
-jlong curr_interval = now - _last_was_full;
+CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
-if ((!CodeCache::needs_flushing()) && (curr_interval > max_interval)) {
+log_sweep("restart_compiler");
-CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
-set_was_full(false);
-// Update the _last_was_full time so we can tell how fast the
-// code cache is filling up
-_last_was_full = os::javaTimeMillis();
-log_sweep("restart_compiler");
-}
 }
 }
 }
 void NMethodSweeper::possibly_sweep() {
 assert(JavaThread::current()->thread_state() == _thread_in_vm, "must run in vm mode");
-if ((!MethodFlushing) || (!_do_sweep)) return;
+if (!MethodFlushing || !sweep_in_progress()) return;
 if (_invocations > 0) {
 // Only one thread at a time will sweep
 jint old = Atomic::cmpxchg( 1, &_sweep_started, 0 );
 if (old != 0) {
 sweep_start = os::javaTimeMillis();
 }
 #endif
 if (PrintMethodFlushing && Verbose) {
 tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_nmethods(), _invocations);
+}
+if (!CompileBroker::should_compile_new_jobs()) {
+// If we have turned off compilations we might as well do full sweeps
+// in order to reach the clean state faster. Otherwise the sleeping compiler
+// threads will slow down sweeping. After a few iterations the cache
+// will be clean and sweeping stops (_resweep will not be set)
+_invocations = 1;
 }
 // We want to visit all nmethods after NmethodSweepFraction
 // invocations so divide the remaining number of nmethods by the
 // remaining number of invocations.  This is only an estimate since
 }
 }
 assert(_invocations > 1 || _current == NULL, "must have scanned the whole cache");
-if (_current == NULL && !_rescan && (_locked_seen || _not_entrant_seen_on_stack)) {
+if (!sweep_in_progress() && !_resweep && (_locked_seen || _not_entrant_seen_on_stack)) {
 // we've completed a scan without making progress but there were
 // nmethods we were unable to process either because they were
 // locked or were still on stack.  We don't have to aggresively
 // clean them up so just stop scanning.  We could scan once more
 // but that complicates the control logic and it's unlikely to
 }
 #endif
 if (_invocations == 1) {
 log_sweep("finished");
+}
+// Sweeper is the only case where memory is released,
+// check here if it is time to restart the compiler.
+if (UseCodeCacheFlushing && !CompileBroker::should_compile_new_jobs() && !CodeCache::needs_flushing()) {
+CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
+log_sweep("restart_compiler");
 }
 }
 class NMethodMarker: public StackObj {
 private:
 } else {
 if (PrintMethodFlushing && Verbose) {
 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (zombie) being marked for reclamation", nm->compile_id(), nm);
 }
 nm->mark_for_reclamation();
-_rescan = true;
+_resweep = true;
 SWEEP(nm);
 }
 } else if (nm->is_not_entrant()) {
 // If there is no current activations of this method on the
 // stack we can safely convert it to a zombie method
 if (nm->can_not_entrant_be_converted()) {
 if (PrintMethodFlushing && Verbose) {
 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (not entrant) being made zombie", nm->compile_id(), nm);
 }
 nm->make_zombie();
-_rescan = true;
+_resweep = true;
 SWEEP(nm);
 } else {
 // Still alive, clean up its inline caches
 MutexLocker cl(CompiledIC_lock);
 nm->cleanup_inline_caches();
 SWEEP(nm);
 // No inline caches will ever point to osr methods, so we can just remove it
 release_nmethod(nm);
 } else {
 nm->make_zombie();
-_rescan = true;
+_resweep = true;
 SWEEP(nm);
 }
 } else {
 assert(nm->is_alive(), "should be alive");
 if (UseCodeCacheFlushing) {
-if ((nm->method()->code() != nm) && !(nm->is_locked_by_vm()) && !(nm->is_osr_method()) &&
+if (nm->is_speculatively_disconnected() && !nm->is_locked_by_vm() && !nm->is_osr_method() &&
-(_traversals > _was_full_traversal+2) && (((uint)nm->compile_id()) < _highest_marked) &&
+(_traversals > _last_flush_traversal_id + 2) && (nm->compile_id() < _highest_marked)) {
-CodeCache::needs_flushing()) {
 // This method has not been called since the forced cleanup happened
 nm->make_not_entrant();
 }
 }
 // stack traversal after the current one, the nmethod will be marked non-entrant and
 // got rid of by normal sweeping. If the method is called, the Method*'s
 // _code field is restored and the Method*/nmethod
 // go back to their normal state.
 void NMethodSweeper::handle_full_code_cache(bool is_full) {
-// Only the first one to notice can advise us to start early cleaning
-if (!is_full){
-jint old = Atomic::cmpxchg( 1, &_advise_to_sweep, 0 );
-if (old != 0) {
-return;
-}
-}
 if (is_full) {
 // Since code cache is full, immediately stop new compiles
-bool did_set = CompileBroker::set_should_compile_new_jobs(CompileBroker::stop_compilation);
+if (CompileBroker::set_should_compile_new_jobs(CompileBroker::stop_compilation)) {
-if (!did_set) {
+log_sweep("disable_compiler");
-// only the first to notice can start the cleaning,
+}
-// others will go back and block
+}
-return;
-}
+// Make sure only one thread can flush
-set_was_full(true);
+// The token is reset after CodeCacheMinimumFlushInterval in scan stacks,
+// no need to check the timeout here.
-// If we run out within MinCodeCacheFlushingInterval of the last unload time, give up
+jint old = Atomic::cmpxchg( 1, &_flush_token, 0 );
-jlong now = os::javaTimeMillis();
+if (old != 0) {
-jlong max_interval = (jlong)MinCodeCacheFlushingInterval * (jlong)1000;
+return;
-jlong curr_interval = now - _last_was_full;
-if (curr_interval < max_interval) {
-_rescan = true;
-log_sweep("disable_compiler", "flushing_interval='" UINT64_FORMAT "'",
-curr_interval/1000);
-return;
-}
 }
 VM_HandleFullCodeCache op(is_full);
 VMThread::execute(&op);
-// rescan again as soon as possible
+// resweep again as soon as possible
-_rescan = true;
+_resweep = true;
 }
 void NMethodSweeper::speculative_disconnect_nmethods(bool is_full) {
 // If there was a race in detecting full code cache, only run
 // one vm op for it or keep the compiler shut off
 debug_only(jlong start = os::javaTimeMillis();)
-if ((!was_full()) && (is_full)) {
-if (!CodeCache::needs_flushing()) {
-log_sweep("restart_compiler");
-CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
-return;
-}
-}
 // Traverse the code cache trying to dump the oldest nmethods
-uint curr_max_comp_id = CompileBroker::get_compilation_id();
+int curr_max_comp_id = CompileBroker::get_compilation_id();
-uint flush_target = ((curr_max_comp_id - _highest_marked) >> 1) + _highest_marked;
+int flush_target = ((curr_max_comp_id - _dead_compile_ids) / CodeCacheFlushingFraction) + _dead_compile_ids;
 log_sweep("start_cleaning");
 nmethod* nm = CodeCache::alive_nmethod(CodeCache::first());
 jint disconnected = 0;
 jint made_not_entrant  = 0;
+jint nmethod_count = 0;
 while ((nm != NULL)){
-uint curr_comp_id = nm->compile_id();
+int curr_comp_id = nm->compile_id();
 // OSR methods cannot be flushed like this. Also, don't flush native methods
 // since they are part of the JDK in most cases
-if (nm->is_in_use() && (!nm->is_osr_method()) && (!nm->is_locked_by_vm()) &&
+if (!nm->is_osr_method() && !nm->is_locked_by_vm() && !nm->is_native_method()) {
-(!nm->is_native_method()) && ((curr_comp_id < flush_target))) {
+// only count methods that can be speculatively disconnected
-if ((nm->method()->code() == nm)) {
+nmethod_count++;
-// This method has not been previously considered for
-// unloading or it was restored already
+if (nm->is_in_use() && (curr_comp_id < flush_target)) {
-CodeCache::speculatively_disconnect(nm);
+if ((nm->method()->code() == nm)) {
-disconnected++;
+// This method has not been previously considered for
-} else if (nm->is_speculatively_disconnected()) {
+// unloading or it was restored already
-// This method was previously considered for preemptive unloading and was not called since then
+CodeCache::speculatively_disconnect(nm);
-CompilationPolicy::policy()->delay_compilation(nm->method());
+disconnected++;
-nm->make_not_entrant();
+} else if (nm->is_speculatively_disconnected()) {
-made_not_entrant++;
+// This method was previously considered for preemptive unloading and was not called since then
-}
+CompilationPolicy::policy()->delay_compilation(nm->method());
+nm->make_not_entrant();
-if (curr_comp_id > _highest_marked) {
+made_not_entrant++;
-_highest_marked = curr_comp_id;
+}
+if (curr_comp_id > _highest_marked) {
+_highest_marked = curr_comp_id;
+}
 }
 }
 nm = CodeCache::alive_nmethod(CodeCache::next(nm));
 }
+// remember how many compile_ids wheren't seen last flush.
+_dead_compile_ids = curr_max_comp_id - nmethod_count;
 log_sweep("stop_cleaning",
 "disconnected='" UINT32_FORMAT "' made_not_entrant='" UINT32_FORMAT "'",
 disconnected, made_not_entrant);
 // Shut off compiler. Sweeper will start over with a new stack scan and
 // traversal cycle and turn it back on if it clears enough space.
-if (was_full()) {
+if (is_full) {
-_last_was_full = os::javaTimeMillis();
+_last_full_flush_time = os::javaTimeMillis();
-CompileBroker::set_should_compile_new_jobs(CompileBroker::stop_compilation);
 }
 // After two more traversals the sweeper will get rid of unrestored nmethods
-_was_full_traversal = _traversals;
+_last_flush_traversal_id = _traversals;
+_resweep = true;
 #ifdef ASSERT
 jlong end = os::javaTimeMillis();
 if(PrintMethodFlushing && Verbose) {
 tty->print_cr("### sweeper: unload time: " INT64_FORMAT, end-start);
 }

Mercurial > hg > graal-compiler

comparison src/share/vm/runtime/sweeper.cpp @ 10206:0cfa93c2fcc4