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8213755: Let nmethods be is_unloading() outside of safepoints

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Reviewed-by: rehn, coleenp, kvn
This commit is contained in:
Erik Österlund 2018-11-22 10:01:38 +01:00
parent c9657d8dcf
commit 1379397c32
8 changed files with 102 additions and 75 deletions
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32
src/hotspot/share/code/nmethod.cpp
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@ -1019,13 +1019,20 @@ void nmethod::mark_as_seen_on_stack() {
// there are no activations on the stack, not in use by the VM,
// and not in use by the ServiceThread)
bool nmethod::can_convert_to_zombie() {
assert(is_not_entrant(), "must be a non-entrant method");
// Note that this is called when the sweeper has observed the nmethod to be
// not_entrant. However, with concurrent code cache unloading, the state
// might have moved on to unloaded if it is_unloading(), due to racing
// concurrent GC threads.
assert(is_not_entrant() || is_unloading(), "must be a non-entrant method");
// Since the nmethod sweeper only does partial sweep the sweeper's traversal
// count can be greater than the stack traversal count before it hits the
// nmethod for the second time.
return stack_traversal_mark()+1 < NMethodSweeper::traversal_count() &&
!is_locked_by_vm();
// If an is_unloading() nmethod is still not_entrant, then it is not safe to
// convert it to zombie due to GC unloading interactions. However, if it
// has become unloaded, then it is okay to convert such nmethods to zombie.
return stack_traversal_mark() + 1 < NMethodSweeper::traversal_count() &&
!is_locked_by_vm() && (!is_unloading() || is_unloaded());
}
void nmethod::inc_decompile_count() {
@ -1093,8 +1100,6 @@ void nmethod::make_unloaded() {
// Unregister must be done before the state change
Universe::heap()->unregister_nmethod(this);
_state = unloaded;
// Log the unloading.
log_state_change();
@ -1110,6 +1115,13 @@ void nmethod::make_unloaded() {
set_osr_link(NULL);
NMethodSweeper::report_state_change(this);
// The release is only needed for compile-time ordering, as accesses
// into the nmethod after the store are not safe due to the sweeper
// being allowed to free it when the store is observed, during
// concurrent nmethod unloading. Therefore, there is no need for
// acquire on the loader side.
OrderAccess::release_store(&_state, (signed char)unloaded);
}
void nmethod::invalidate_osr_method() {
@ -1913,11 +1925,11 @@ void nmethod::check_all_dependencies(DepChange& changes) {
// Iterate over live nmethods and check dependencies of all nmethods that are not
// marked for deoptimization. A particular dependency is only checked once.
NMethodIterator iter;
NMethodIterator iter(NMethodIterator::only_alive_and_not_unloading);
while(iter.next()) {
nmethod* nm = iter.method();
// Only notify for live nmethods
if (nm->is_alive() && !nm->is_marked_for_deoptimization()) {
if (!nm->is_marked_for_deoptimization()) {
for (Dependencies::DepStream deps(nm); deps.next(); ) {
// Construct abstraction of a dependency.
DependencySignature* current_sig = new DependencySignature(deps);
@ -2912,7 +2924,7 @@ void nmethod::maybe_invalidate_installed_code() {
// Update the values in the InstalledCode instance if it still refers to this nmethod
nmethod* nm = (nmethod*)InstalledCode::address(installed_code);
if (nm == this) {
if (!is_alive()) {
if (!is_alive() || is_unloading()) {
// Break the link between nmethod and InstalledCode such that the nmethod
// can subsequently be flushed safely. The link must be maintained while
// the method could have live activations since invalidateInstalledCode
@ -2927,7 +2939,7 @@ void nmethod::maybe_invalidate_installed_code() {
}
}
}
if (!is_alive()) {
if (!is_alive() || is_unloading()) {
// Clear these out after the nmethod has been unregistered and any
// updates to the InstalledCode instance have been performed.
clear_jvmci_installed_code();
@ -2951,7 +2963,7 @@ void nmethod::invalidate_installed_code(Handle installedCode, TRAPS) {
{
MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);
// This relationship can only be checked safely under a lock
assert(!nm->is_alive() || nm->jvmci_installed_code() == installedCode(), "sanity check");
assert(!nm->is_alive() || nm->is_unloading() || nm->jvmci_installed_code() == installedCode(), "sanity check");
}
#endif