Skip to content

8364929: Assign unique id to each AdapterBlob stored in AOTCodeCache #27553

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 5 commits into from
Closed

8364929: Assign unique id to each AdapterBlob stored in AOTCodeCache #27553

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
737b908
8364929: Assign unique id to each AdapterBlob stored in AOTCodeCache
ashu-mehra Jul 30, 2025
93906b1
Add comment explaining the reason for using largest adapter id of the
ashu-mehra Sep 30, 2025
84edc05
Add assert for _id_counter == 0
ashu-mehra Sep 30, 2025
46bda6b
Replace overflow check if guarantee statement
ashu-mehra Oct 2, 2025
206148f
Address Ioi's comments
ashu-mehra Oct 2, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
35 changes: 24 additions & 11 deletions src/hotspot/share/runtime/sharedRuntime.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2520,6 +2520,7 @@ ArchivedAdapterTable AdapterHandlerLibrary::_aot_adapter_handler_table;
#endif // INCLUDE_CDS
static const int AdapterHandlerLibrary_size = 16*K;
BufferBlob* AdapterHandlerLibrary::_buffer = nullptr;
volatile uint AdapterHandlerLibrary::_id_counter = 0;

BufferBlob* AdapterHandlerLibrary::buffer_blob() {
assert(_buffer != nullptr, "should be initialized");
Expand Down Expand Up @@ -2600,7 +2601,9 @@ void AdapterHandlerLibrary::initialize() {
}

AdapterHandlerEntry* AdapterHandlerLibrary::new_entry(AdapterFingerPrint* fingerprint) {
return AdapterHandlerEntry::allocate(fingerprint);
uint id = (uint)AtomicAccess::add((int*)&_id_counter, 1);
assert(id > 0, "we can never overflow because AOT cache cannot contain more than 2^32 methods");
return AdapterHandlerEntry::allocate(id, fingerprint);
}

AdapterHandlerEntry* AdapterHandlerLibrary::get_simple_adapter(const methodHandle& method) {
Expand Down Expand Up @@ -2754,8 +2757,8 @@ AdapterHandlerEntry* AdapterHandlerLibrary::get_adapter(const methodHandle& meth

void AdapterHandlerLibrary::lookup_aot_cache(AdapterHandlerEntry* handler) {
ResourceMark rm;
const char* name = AdapterHandlerLibrary::name(handler->fingerprint());
const uint32_t id = AdapterHandlerLibrary::id(handler->fingerprint());
const char* name = AdapterHandlerLibrary::name(handler);
const uint32_t id = AdapterHandlerLibrary::id(handler);

CodeBlob* blob = AOTCodeCache::load_code_blob(AOTCodeEntry::Adapter, id, name);
if (blob != nullptr) {
Expand Down Expand Up @@ -2850,8 +2853,8 @@ bool AdapterHandlerLibrary::generate_adapter_code(AdapterHandlerEntry* handler,
handler->set_adapter_blob(adapter_blob);
if (!is_transient && AOTCodeCache::is_dumping_adapter()) {
// try to save generated code
const char* name = AdapterHandlerLibrary::name(handler->fingerprint());
const uint32_t id = AdapterHandlerLibrary::id(handler->fingerprint());
const char* name = AdapterHandlerLibrary::name(handler);
const uint32_t id = AdapterHandlerLibrary::id(handler);
bool success = AOTCodeCache::store_code_blob(*adapter_blob, AOTCodeEntry::Adapter, id, name);
assert(success || !AOTCodeCache::is_dumping_adapter(), "caching of adapter must be disabled");
}
Expand Down Expand Up @@ -2991,11 +2994,22 @@ void AdapterHandlerEntry::link() {
}

void AdapterHandlerLibrary::link_aot_adapters() {
uint max_id = 0;
assert(AOTCodeCache::is_using_adapter(), "AOT adapters code should be available");
_aot_adapter_handler_table.iterate([](AdapterHandlerEntry* entry) {
/* It is possible that some adapters generated in assembly phase are not stored in the cache.
* That implies adapter ids of the adapters in the cache may not be contiguous.
* If the size of the _aot_adapter_handler_table is used to initialize _id_counter, then it may
* result in collision of adapter ids between AOT stored handlers and runtime generated handlers.
* To avoid such situation, initialize the _id_counter with the largest adapter id among the AOT stored handlers.
*/
_aot_adapter_handler_table.iterate([&](AdapterHandlerEntry* entry) {
assert(!entry->is_linked(), "AdapterHandlerEntry is already linked!");
entry->link();
max_id = MAX2(max_id, entry->id());
});
// Set adapter id to the maximum id found in the AOTCache
assert(_id_counter == 0, "Did not expect new AdapterHandlerEntry to be created at this stage");
_id_counter = max_id;
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is this number the same as number of AOT adapter entries in AdapterHandlerEntry? Do we need max_id? In which case they could be different?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is this number the same as number of AOT adapter entries in AdapterHandlerEntry? Do we need max_id? In which case they could be different?

I thought about this. It is possible that some adapters generated in assembly phase are not stored in the cache. So there may be gaps in the adapter ids of the adapters in the cache. In such case using the number of entries to decide next adapter id can result in clash of adapter id with the runtime generated adapters. But the maximum id ensures adapter ids are never reused.

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Please add comment about that.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Done

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Now only assert(_id_counter ==0) is missing.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added the assert before _id_counter = max_id

}

// This method is called during production run to lookup simple adapters
Expand Down Expand Up @@ -3360,13 +3374,12 @@ bool AdapterHandlerLibrary::contains(const CodeBlob* b) {
return found;
}

const char* AdapterHandlerLibrary::name(AdapterFingerPrint* fingerprint) {
return fingerprint->as_basic_args_string();
const char* AdapterHandlerLibrary::name(AdapterHandlerEntry* handler) {
return handler->fingerprint()->as_basic_args_string();
}

uint32_t AdapterHandlerLibrary::id(AdapterFingerPrint* fingerprint) {
unsigned int hash = fingerprint->compute_hash();
return hash;
uint32_t AdapterHandlerLibrary::id(AdapterHandlerEntry* handler) {
return handler->id();
}

void AdapterHandlerLibrary::print_handler_on(outputStream* st, const CodeBlob* b) {
Expand Down
14 changes: 9 additions & 5 deletions src/hotspot/share/runtime/sharedRuntime.hpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -686,6 +686,7 @@ class AdapterHandlerEntry : public MetaspaceObj {
private:
AdapterFingerPrint* _fingerprint;
AdapterBlob* _adapter_blob;
uint _id;
bool _linked;

static const char *_entry_names[];
Expand All @@ -697,9 +698,10 @@ class AdapterHandlerEntry : public MetaspaceObj {
int _saved_code_length;
#endif

AdapterHandlerEntry(AdapterFingerPrint* fingerprint) :
AdapterHandlerEntry(int id, AdapterFingerPrint* fingerprint) :
_fingerprint(fingerprint),
_adapter_blob(nullptr),
_id(id),
_linked(false)
#ifdef ASSERT
, _saved_code(nullptr),
Expand All @@ -720,8 +722,8 @@ class AdapterHandlerEntry : public MetaspaceObj {
}

public:
static AdapterHandlerEntry* allocate(AdapterFingerPrint* fingerprint) {
return new(0) AdapterHandlerEntry(fingerprint);
static AdapterHandlerEntry* allocate(uint id, AdapterFingerPrint* fingerprint) {
return new(0) AdapterHandlerEntry(id, fingerprint);
}

static void deallocate(AdapterHandlerEntry *handler) {
Expand Down Expand Up @@ -772,6 +774,7 @@ class AdapterHandlerEntry : public MetaspaceObj {
AdapterBlob* adapter_blob() const { return _adapter_blob; }
bool is_linked() const { return _linked; }

uint id() const { return _id; }
AdapterFingerPrint* fingerprint() const { return _fingerprint; }

#ifdef ASSERT
Expand All @@ -798,6 +801,7 @@ class ArchivedAdapterTable;
class AdapterHandlerLibrary: public AllStatic {
friend class SharedRuntime;
private:
static volatile uint _id_counter; // counter for generating unique adapter ids, range = [1,UINT_MAX]
static BufferBlob* _buffer; // the temporary code buffer in CodeCache
static AdapterHandlerEntry* _no_arg_handler;
static AdapterHandlerEntry* _int_arg_handler;
Expand Down Expand Up @@ -837,8 +841,8 @@ class AdapterHandlerLibrary: public AllStatic {
static void print_handler(const CodeBlob* b) { print_handler_on(tty, b); }
static void print_handler_on(outputStream* st, const CodeBlob* b);
static bool contains(const CodeBlob* b);
static const char* name(AdapterFingerPrint* fingerprint);
static uint32_t id(AdapterFingerPrint* fingerprint);
static const char* name(AdapterHandlerEntry* handler);
static uint32_t id(AdapterHandlerEntry* handler);
#ifndef PRODUCT
static void print_statistics();
#endif // PRODUCT
Expand Down