Mercurial > hg > graal-compiler
view src/share/vm/runtime/sweeper.cpp @ 12350:ab68fc0101ce
8025855: Simplify GenRemSet code slightly
Summary: Remove a few redundant switch-statements
Reviewed-by: jcoomes, tschatzl
author | jwilhelm |
---|---|
date | Thu, 03 Oct 2013 13:19:19 +0200 |
parents | ab274453d37f |
children | 510fbd28919c |
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/* * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "code/codeCache.hpp" #include "code/compiledIC.hpp" #include "code/icBuffer.hpp" #include "code/nmethod.hpp" #include "compiler/compileBroker.hpp" #include "memory/resourceArea.hpp" #include "oops/method.hpp" #include "runtime/atomic.hpp" #include "runtime/compilationPolicy.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/os.hpp" #include "runtime/sweeper.hpp" #include "runtime/vm_operations.hpp" #include "trace/tracing.hpp" #include "utilities/events.hpp" #include "utilities/xmlstream.hpp" #ifdef ASSERT #define SWEEP(nm) record_sweep(nm, __LINE__) // Sweeper logging code class SweeperRecord { public: int traversal; int invocation; int compile_id; long traversal_mark; int state; const char* kind; address vep; address uep; int line; void print() { tty->print_cr("traversal = %d invocation = %d compile_id = %d %s uep = " PTR_FORMAT " vep = " PTR_FORMAT " state = %d traversal_mark %d line = %d", traversal, invocation, compile_id, kind == NULL ? "" : kind, uep, vep, state, traversal_mark, line); } }; static int _sweep_index = 0; static SweeperRecord* _records = NULL; void NMethodSweeper::report_events(int id, address entry) { if (_records != NULL) { for (int i = _sweep_index; i < SweeperLogEntries; i++) { if (_records[i].uep == entry || _records[i].vep == entry || _records[i].compile_id == id) { _records[i].print(); } } for (int i = 0; i < _sweep_index; i++) { if (_records[i].uep == entry || _records[i].vep == entry || _records[i].compile_id == id) { _records[i].print(); } } } } void NMethodSweeper::report_events() { if (_records != NULL) { for (int i = _sweep_index; i < SweeperLogEntries; i++) { // skip empty records if (_records[i].vep == NULL) continue; _records[i].print(); } for (int i = 0; i < _sweep_index; i++) { // skip empty records if (_records[i].vep == NULL) continue; _records[i].print(); } } } void NMethodSweeper::record_sweep(nmethod* nm, int line) { if (_records != NULL) { _records[_sweep_index].traversal = _traversals; _records[_sweep_index].traversal_mark = nm->_stack_traversal_mark; _records[_sweep_index].invocation = _invocations; _records[_sweep_index].compile_id = nm->compile_id(); _records[_sweep_index].kind = nm->compile_kind(); _records[_sweep_index].state = nm->_state; _records[_sweep_index].vep = nm->verified_entry_point(); _records[_sweep_index].uep = nm->entry_point(); _records[_sweep_index].line = line; _sweep_index = (_sweep_index + 1) % SweeperLogEntries; } } #else #define SWEEP(nm) #endif long NMethodSweeper::_traversals = 0; // No. of stack traversals performed nmethod* NMethodSweeper::_current = NULL; // Current nmethod int NMethodSweeper::_seen = 0 ; // No. of nmethods we have currently processed in current pass of CodeCache int NMethodSweeper::_flushed_count = 0; // Nof. nmethods flushed in current sweep int NMethodSweeper::_zombified_count = 0; // Nof. nmethods made zombie in current sweep int NMethodSweeper::_marked_count = 0; // Nof. nmethods marked for reclaim in current sweep 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::_resweep = false; jint NMethodSweeper::_flush_token = 0; jlong NMethodSweeper::_last_full_flush_time = 0; int NMethodSweeper::_highest_marked = 0; int NMethodSweeper::_dead_compile_ids = 0; long NMethodSweeper::_last_flush_traversal_id = 0; int NMethodSweeper::_number_of_flushes = 0; // Total of full traversals caused by full cache int NMethodSweeper::_total_nof_methods_reclaimed = 0; jlong NMethodSweeper::_total_time_sweeping = 0; jlong NMethodSweeper::_total_time_this_sweep = 0; jlong NMethodSweeper::_peak_sweep_time = 0; jlong NMethodSweeper::_peak_sweep_fraction_time = 0; jlong NMethodSweeper::_total_disconnect_time = 0; jlong NMethodSweeper::_peak_disconnect_time = 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. if (cb->is_nmethod() && ((nmethod*)cb)->is_not_entrant()) { ((nmethod*)cb)->mark_as_seen_on_stack(); } } }; 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; // No need to synchronize access, since this is always executed at a // safepoint. // 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 (!sweep_in_progress() && _resweep) { _seen = 0; _invocations = NmethodSweepFraction; _current = CodeCache::first_nmethod(); _traversals += 1; _total_time_this_sweep = 0; 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. _resweep = false; _locked_seen = 0; _not_entrant_seen_on_stack = 0; } if (UseCodeCacheFlushing) { // only allow new flushes after the interval is complete. jlong now = os::javaTimeMillis(); jlong max_interval = (jlong)MinCodeCacheFlushingInterval * (jlong)1000; jlong curr_interval = now - _last_full_flush_time; if (curr_interval > max_interval) { _flush_token = 0; } if (!CodeCache::needs_flushing() && !CompileBroker::should_compile_new_jobs()) { CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation); log_sweep("restart_compiler"); } } } void NMethodSweeper::possibly_sweep() { assert(JavaThread::current()->thread_state() == _thread_in_vm, "must run in vm mode"); 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) { return; } #ifdef ASSERT if (LogSweeper && _records == NULL) { // Create the ring buffer for the logging code _records = NEW_C_HEAP_ARRAY(SweeperRecord, SweeperLogEntries, mtGC); memset(_records, 0, sizeof(SweeperRecord) * SweeperLogEntries); } #endif if (_invocations > 0) { sweep_code_cache(); _invocations--; } _sweep_started = 0; } } void NMethodSweeper::sweep_code_cache() { jlong sweep_start_counter = os::elapsed_counter(); _flushed_count = 0; _zombified_count = 0; _marked_count = 0; 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 // the number of nmethods changes during the sweep so the final // stage must iterate until it there are no more nmethods. int todo = (CodeCache::nof_nmethods() - _seen) / _invocations; int swept_count = 0; assert(!SafepointSynchronize::is_at_safepoint(), "should not be in safepoint when we get here"); assert(!CodeCache_lock->owned_by_self(), "just checking"); { MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); // The last invocation iterates until there are no more nmethods for (int i = 0; (i < todo || _invocations == 1) && _current != NULL; i++) { swept_count++; if (SafepointSynchronize::is_synchronizing()) { // Safepoint request if (PrintMethodFlushing && Verbose) { tty->print_cr("### Sweep at %d out of %d, invocation: %d, yielding to safepoint", _seen, CodeCache::nof_nmethods(), _invocations); } MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); assert(Thread::current()->is_Java_thread(), "should be java thread"); JavaThread* thread = (JavaThread*)Thread::current(); ThreadBlockInVM tbivm(thread); thread->java_suspend_self(); } // Since we will give up the CodeCache_lock, always skip ahead // to the next nmethod. Other blobs can be deleted by other // threads but nmethods are only reclaimed by the sweeper. nmethod* next = CodeCache::next_nmethod(_current); // Now ready to process nmethod and give up CodeCache_lock { MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); process_nmethod(_current); } _seen++; _current = next; } } assert(_invocations > 1 || _current == NULL, "must have scanned the whole cache"); 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 // matter much. if (PrintMethodFlushing) { tty->print_cr("### Couldn't make progress on some nmethods so stopping sweep"); } } jlong sweep_end_counter = os::elapsed_counter(); jlong sweep_time = sweep_end_counter - sweep_start_counter; _total_time_sweeping += sweep_time; _total_time_this_sweep += sweep_time; _peak_sweep_fraction_time = MAX2(sweep_time, _peak_sweep_fraction_time); _total_nof_methods_reclaimed += _flushed_count; EventSweepCodeCache event(UNTIMED); if (event.should_commit()) { event.set_starttime(sweep_start_counter); event.set_endtime(sweep_end_counter); event.set_sweepIndex(_traversals); event.set_sweepFractionIndex(NmethodSweepFraction - _invocations + 1); event.set_sweptCount(swept_count); event.set_flushedCount(_flushed_count); event.set_markedCount(_marked_count); event.set_zombifiedCount(_zombified_count); event.commit(); } #ifdef ASSERT if(PrintMethodFlushing) { tty->print_cr("### sweeper: sweep time(%d): " INT64_FORMAT, _invocations, (jlong)sweep_time); } #endif if (_invocations == 1) { _peak_sweep_time = MAX2(_peak_sweep_time, _total_time_this_sweep); 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: CompilerThread* _thread; public: NMethodMarker(nmethod* nm) { _thread = CompilerThread::current(); if (!nm->is_zombie() && !nm->is_unloaded()) { // Only expose live nmethods for scanning _thread->set_scanned_nmethod(nm); } } ~NMethodMarker() { _thread->set_scanned_nmethod(NULL); } }; void NMethodSweeper::release_nmethod(nmethod *nm) { // Clean up any CompiledICHolders { ResourceMark rm; MutexLocker ml_patch(CompiledIC_lock); RelocIterator iter(nm); while (iter.next()) { if (iter.type() == relocInfo::virtual_call_type) { CompiledIC::cleanup_call_site(iter.virtual_call_reloc()); } } } MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); nm->flush(); } void NMethodSweeper::process_nmethod(nmethod *nm) { assert(!CodeCache_lock->owned_by_self(), "just checking"); // Make sure this nmethod doesn't get unloaded during the scan, // since the locks acquired below might safepoint. NMethodMarker nmm(nm); SWEEP(nm); // Skip methods that are currently referenced by the VM if (nm->is_locked_by_vm()) { // But still remember to clean-up inline caches for alive nmethods if (nm->is_alive()) { // Clean-up all inline caches that points to zombie/non-reentrant methods MutexLocker cl(CompiledIC_lock); nm->cleanup_inline_caches(); SWEEP(nm); } else { _locked_seen++; SWEEP(nm); } return; } if (nm->is_zombie()) { // If it is first time, we see nmethod then we mark it. Otherwise, // we reclame it. When we have seen a zombie method twice, we know that // there are no inline caches that refer to it. if (nm->is_marked_for_reclamation()) { assert(!nm->is_locked_by_vm(), "must not flush locked nmethods"); if (PrintMethodFlushing && Verbose) { tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (marked for reclamation) being flushed", nm->compile_id(), nm); } release_nmethod(nm); _flushed_count++; } else { if (PrintMethodFlushing && Verbose) { tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (zombie) being marked for reclamation", nm->compile_id(), nm); } nm->mark_for_reclamation(); _resweep = true; _marked_count++; 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(); _resweep = true; _zombified_count++; SWEEP(nm); } else { // Still alive, clean up its inline caches MutexLocker cl(CompiledIC_lock); nm->cleanup_inline_caches(); // we coudn't transition this nmethod so don't immediately // request a rescan. If this method stays on the stack for a // long time we don't want to keep rescanning the code cache. _not_entrant_seen_on_stack++; SWEEP(nm); } } else if (nm->is_unloaded()) { // Unloaded code, just make it a zombie if (PrintMethodFlushing && Verbose) tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (unloaded) being made zombie", nm->compile_id(), nm); if (nm->is_osr_method()) { SWEEP(nm); // No inline caches will ever point to osr methods, so we can just remove it release_nmethod(nm); _flushed_count++; } else { nm->make_zombie(); _resweep = true; _zombified_count++; SWEEP(nm); } } else { assert(nm->is_alive(), "should be alive"); if (UseCodeCacheFlushing) { if (nm->is_speculatively_disconnected() && !nm->is_locked_by_vm() && !nm->is_osr_method() && (_traversals > _last_flush_traversal_id + 2) && (nm->compile_id() < _highest_marked)) { // This method has not been called since the forced cleanup happened nm->make_not_entrant(); } } // Clean-up all inline caches that points to zombie/non-reentrant methods MutexLocker cl(CompiledIC_lock); nm->cleanup_inline_caches(); SWEEP(nm); } } // Code cache unloading: when compilers notice the code cache is getting full, // they will call a vm op that comes here. This code attempts to speculatively // unload the oldest half of the nmethods (based on the compile job id) by // saving the old code in a list in the CodeCache. Then // execution resumes. If a method so marked is not called by the second sweeper // 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) { if (is_full) { // Since code cache is full, immediately stop new compiles if (CompileBroker::set_should_compile_new_jobs(CompileBroker::stop_compilation)) { log_sweep("disable_compiler"); } } // Make sure only one thread can flush // The token is reset after CodeCacheMinimumFlushInterval in scan stacks, // no need to check the timeout here. jint old = Atomic::cmpxchg( 1, &_flush_token, 0 ); if (old != 0) { return; } VM_HandleFullCodeCache op(is_full); VMThread::execute(&op); // resweep again as soon as possible _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 jlong disconnect_start_counter = os::elapsed_counter(); // Traverse the code cache trying to dump the oldest nmethods int curr_max_comp_id = CompileBroker::get_compilation_id(); 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)){ 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_osr_method() && !nm->is_locked_by_vm() && !nm->is_native_method()) { // only count methods that can be speculatively disconnected nmethod_count++; if (nm->is_in_use() && (curr_comp_id < flush_target)) { if ((nm->method()->code() == nm)) { // This method has not been previously considered for // unloading or it was restored already CodeCache::speculatively_disconnect(nm); disconnected++; } else if (nm->is_speculatively_disconnected()) { // This method was previously considered for preemptive unloading and was not called since then CompilationPolicy::policy()->delay_compilation(nm->method()); nm->make_not_entrant(); made_not_entrant++; } 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 (is_full) { _last_full_flush_time = os::javaTimeMillis(); } jlong disconnect_end_counter = os::elapsed_counter(); jlong disconnect_time = disconnect_end_counter - disconnect_start_counter; _total_disconnect_time += disconnect_time; _peak_disconnect_time = MAX2(disconnect_time, _peak_disconnect_time); EventCleanCodeCache event(UNTIMED); if (event.should_commit()) { event.set_starttime(disconnect_start_counter); event.set_endtime(disconnect_end_counter); event.set_disconnectedCount(disconnected); event.set_madeNonEntrantCount(made_not_entrant); event.commit(); } _number_of_flushes++; // After two more traversals the sweeper will get rid of unrestored nmethods _last_flush_traversal_id = _traversals; _resweep = true; #ifdef ASSERT if(PrintMethodFlushing && Verbose) { tty->print_cr("### sweeper: unload time: " INT64_FORMAT, (jlong)disconnect_time); } #endif } // Print out some state information about the current sweep and the // state of the code cache if it's requested. void NMethodSweeper::log_sweep(const char* msg, const char* format, ...) { if (PrintMethodFlushing) { stringStream s; // Dump code cache state into a buffer before locking the tty, // because log_state() will use locks causing lock conflicts. CodeCache::log_state(&s); ttyLocker ttyl; tty->print("### sweeper: %s ", msg); if (format != NULL) { va_list ap; va_start(ap, format); tty->vprint(format, ap); va_end(ap); } tty->print_cr(s.as_string()); } if (LogCompilation && (xtty != NULL)) { stringStream s; // Dump code cache state into a buffer before locking the tty, // because log_state() will use locks causing lock conflicts. CodeCache::log_state(&s); ttyLocker ttyl; xtty->begin_elem("sweeper state='%s' traversals='" INTX_FORMAT "' ", msg, (intx)traversal_count()); if (format != NULL) { va_list ap; va_start(ap, format); xtty->vprint(format, ap); va_end(ap); } xtty->print(s.as_string()); xtty->stamp(); xtty->end_elem(); } }