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7145569: G1: optimize nmethods scanning

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Add a list of nmethods to the RSet for a region that contain references into the region. Skip scanning the code cache during root scanning and scan the nmethod lists during RSet scanning instead.

Reviewed-by: tschatzl, brutisso, mgerdin, twisti, kvn
This commit is contained in:
John Cuthbertson 2013-08-15 10:52:18 +02:00
parent c144b8c30f
commit f63547bf71
22 changed files with 1256 additions and 476 deletions
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36
hotspot/src/share/vm/code/nmethod.cpp
View file

@ -687,6 +687,7 @@ nmethod::nmethod(
code_buffer->copy_values_to(this);
if (ScavengeRootsInCode && detect_scavenge_root_oops()) {
CodeCache::add_scavenge_root_nmethod(this);
Universe::heap()->register_nmethod(this);
}
debug_only(verify_scavenge_root_oops());
CodeCache::commit(this);
@ -881,6 +882,7 @@ nmethod::nmethod(
dependencies->copy_to(this);
if (ScavengeRootsInCode && detect_scavenge_root_oops()) {
CodeCache::add_scavenge_root_nmethod(this);
Universe::heap()->register_nmethod(this);
}
debug_only(verify_scavenge_root_oops());
@ -1300,6 +1302,13 @@ bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
methodHandle the_method(method());
No_Safepoint_Verifier nsv;
// during patching, depending on the nmethod state we must notify the GC that
// code has been unloaded, unregistering it. We cannot do this right while
// holding the Patching_lock because we need to use the CodeCache_lock. This
// would be prone to deadlocks.
// This flag is used to remember whether we need to later lock and unregister.
bool nmethod_needs_unregister = false;
{
// invalidate osr nmethod before acquiring the patching lock since
// they both acquire leaf locks and we don't want a deadlock.
@ -1332,6 +1341,13 @@ bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
inc_decompile_count();
}
// If the state is becoming a zombie, signal to unregister the nmethod with
// the heap.
// This nmethod may have already been unloaded during a full GC.
if ((state == zombie) && !is_unloaded()) {
nmethod_needs_unregister = true;
}
// Change state
_state = state;
@ -1367,6 +1383,9 @@ bool nmethod::make_not_entrant_or_zombie(unsigned int state) {
// safepoint can sneak in, otherwise the oops used by the
// dependency logic could have become stale.
MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
if (nmethod_needs_unregister) {
Universe::heap()->unregister_nmethod(this);
}
flush_dependencies(NULL);
}
@ -1817,21 +1836,10 @@ void nmethod::metadata_do(void f(Metadata*)) {
if (_method != NULL) f(_method);
}
// This method is called twice during GC -- once while
// tracing the "active" nmethods on thread stacks during
// the (strong) marking phase, and then again when walking
// the code cache contents during the weak roots processing
// phase. The two uses are distinguished by means of the
// 'do_strong_roots_only' flag, which is true in the first
// case. We want to walk the weak roots in the nmethod
// only in the second case. The weak roots in the nmethod
// are the oops in the ExceptionCache and the InlineCache
// oops.
void nmethod::oops_do(OopClosure* f, bool do_strong_roots_only) {
void nmethod::oops_do(OopClosure* f, bool allow_zombie) {
// make sure the oops ready to receive visitors
assert(!is_zombie() && !is_unloaded(),
"should not call follow on zombie or unloaded nmethod");
assert(allow_zombie || !is_zombie(), "should not call follow on zombie nmethod");
assert(!is_unloaded(), "should not call follow on unloaded nmethod");
// If the method is not entrant or zombie then a JMP is plastered over the
// first few bytes. If an oop in the old code was there, that oop