--- a/hotspot/src/share/vm/runtime/sweeper.cpp Wed Jul 07 12:40:01 2010 -0700
+++ b/hotspot/src/share/vm/runtime/sweeper.cpp Thu Jul 08 14:29:44 2010 -0700
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2010, 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
@@ -27,14 +27,15 @@
long NMethodSweeper::_traversals = 0; // No. of stack traversals performed
nmethod* NMethodSweeper::_current = NULL; // Current nmethod
-int NMethodSweeper::_seen = 0 ; // No. of blobs we have currently processed in current pass of CodeCache
-int NMethodSweeper::_invocations = 0; // No. of invocations left until we are completed with this pass
+int NMethodSweeper::_seen = 0 ; // No. of nmethods we have currently processed in current pass of CodeCache
+
+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::_do_sweep = false;
-jint NMethodSweeper::_sweep_started = 0;
bool NMethodSweeper::_was_full = false;
jint NMethodSweeper::_advise_to_sweep = 0;
jlong NMethodSweeper::_last_was_full = 0;
@@ -108,23 +109,14 @@
// code cache is filling up
_last_was_full = os::javaTimeMillis();
- if (PrintMethodFlushing) {
- tty->print_cr("### sweeper: Live blobs:" UINT32_FORMAT "/Free code cache:" SIZE_FORMAT " bytes, restarting compiler",
- CodeCache::nof_blobs(), CodeCache::unallocated_capacity());
- }
- if (LogCompilation && (xtty != NULL)) {
- ttyLocker ttyl;
- xtty->begin_elem("restart_compiler live_blobs='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'",
- CodeCache::nof_blobs(), CodeCache::unallocated_capacity());
- xtty->stamp();
- xtty->end_elem();
- }
+ 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 (_invocations > 0) {
@@ -133,32 +125,31 @@
if (old != 0) {
return;
}
- sweep_code_cache();
+ if (_invocations > 0) {
+ sweep_code_cache();
+ _invocations--;
+ }
+ _sweep_started = 0;
}
- _sweep_started = 0;
}
void NMethodSweeper::sweep_code_cache() {
#ifdef ASSERT
jlong sweep_start;
- if(PrintMethodFlushing) {
+ if (PrintMethodFlushing) {
sweep_start = os::javaTimeMillis();
}
#endif
if (PrintMethodFlushing && Verbose) {
- tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_blobs(), _invocations);
+ tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_nmethods(), _invocations);
}
- // We want to visit all nmethods after NmethodSweepFraction invocations.
- // If invocation is 1 we do the rest
- int todo = CodeCache::nof_blobs();
- if (_invocations > 1) {
- todo = (CodeCache::nof_blobs() - _seen) / _invocations;
- }
-
- // Compilers may check to sweep more often than stack scans happen,
- // don't keep trying once it is all scanned
- _invocations--;
+ // 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;
assert(!SafepointSynchronize::is_at_safepoint(), "should not be in safepoint when we get here");
assert(!CodeCache_lock->owned_by_self(), "just checking");
@@ -166,11 +157,12 @@
{
MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
- for(int i = 0; i < todo && _current != NULL; i++) {
+ // The last invocation iterates until there are no more nmethods
+ for (int i = 0; (i < todo || _invocations == 1) && _current != NULL; i++) {
- // Since we will give up the CodeCache_lock, always skip ahead to an nmethod.
- // Other blobs can be deleted by other threads
- // Read next before we potentially delete current
+ // 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
@@ -183,6 +175,8 @@
}
}
+ assert(_invocations > 1 || _current == NULL, "must have scanned the whole cache");
+
if (_current == NULL && !_rescan && (_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
@@ -201,6 +195,10 @@
tty->print_cr("### sweeper: sweep time(%d): " INT64_FORMAT, _invocations, sweep_end - sweep_start);
}
#endif
+
+ if (_invocations == 1) {
+ log_sweep("finished");
+ }
}
@@ -223,7 +221,7 @@
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 referes to it.
+ // 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) {
@@ -320,16 +318,8 @@
jlong curr_interval = now - _last_was_full;
if (curr_interval < max_interval) {
_rescan = true;
- if (PrintMethodFlushing) {
- tty->print_cr("### handle full too often, turning off compiler");
- }
- if (LogCompilation && (xtty != NULL)) {
- ttyLocker ttyl;
- xtty->begin_elem("disable_compiler flushing_interval='" UINT64_FORMAT "' live_blobs='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'",
- curr_interval/1000, CodeCache::nof_blobs(), CodeCache::unallocated_capacity());
- xtty->stamp();
- xtty->end_elem();
- }
+ log_sweep("disable_compiler", "flushing_interval='" UINT64_FORMAT "'",
+ curr_interval/1000);
return;
}
}
@@ -349,17 +339,7 @@
if ((!was_full()) && (is_full)) {
if (!CodeCache::needs_flushing()) {
- if (PrintMethodFlushing) {
- tty->print_cr("### sweeper: Live blobs:" UINT32_FORMAT "/Free code cache:" SIZE_FORMAT " bytes, restarting compiler",
- CodeCache::nof_blobs(), CodeCache::unallocated_capacity());
- }
- if (LogCompilation && (xtty != NULL)) {
- ttyLocker ttyl;
- xtty->begin_elem("restart_compiler live_blobs='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'",
- CodeCache::nof_blobs(), CodeCache::unallocated_capacity());
- xtty->stamp();
- xtty->end_elem();
- }
+ log_sweep("restart_compiler");
CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
return;
}
@@ -368,17 +348,7 @@
// Traverse the code cache trying to dump the oldest nmethods
uint curr_max_comp_id = CompileBroker::get_compilation_id();
uint flush_target = ((curr_max_comp_id - _highest_marked) >> 1) + _highest_marked;
- if (PrintMethodFlushing && Verbose) {
- tty->print_cr("### Cleaning code cache: Live blobs:" UINT32_FORMAT "/Free code cache:" SIZE_FORMAT " bytes",
- CodeCache::nof_blobs(), CodeCache::unallocated_capacity());
- }
- if (LogCompilation && (xtty != NULL)) {
- ttyLocker ttyl;
- xtty->begin_elem("start_cleaning_code_cache live_blobs='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'",
- CodeCache::nof_blobs(), CodeCache::unallocated_capacity());
- xtty->stamp();
- xtty->end_elem();
- }
+ log_sweep("start_cleaning");
nmethod* nm = CodeCache::alive_nmethod(CodeCache::first());
jint disconnected = 0;
@@ -411,13 +381,9 @@
nm = CodeCache::alive_nmethod(CodeCache::next(nm));
}
- if (LogCompilation && (xtty != NULL)) {
- ttyLocker ttyl;
- xtty->begin_elem("stop_cleaning_code_cache disconnected='" UINT32_FORMAT "' made_not_entrant='" UINT32_FORMAT "' live_blobs='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'",
- disconnected, made_not_entrant, CodeCache::nof_blobs(), CodeCache::unallocated_capacity());
- xtty->stamp();
- xtty->end_elem();
- }
+ 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.
@@ -435,3 +401,38 @@
}
#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) {
+ 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(" total_blobs='" UINT32_FORMAT "' nmethods='" UINT32_FORMAT "'"
+ " adapters='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'",
+ CodeCache::nof_blobs(), CodeCache::nof_nmethods(), CodeCache::nof_adapters(), CodeCache::unallocated_capacity());
+ }
+
+ if (LogCompilation && (xtty != NULL)) {
+ 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(" total_blobs='" UINT32_FORMAT "' nmethods='" UINT32_FORMAT "'"
+ " adapters='" UINT32_FORMAT "' free_code_cache='" SIZE_FORMAT "'",
+ CodeCache::nof_blobs(), CodeCache::nof_nmethods(), CodeCache::nof_adapters(), CodeCache::unallocated_capacity());
+ xtty->stamp();
+ xtty->end_elem();
+ }
+}