On Wed, 31 Aug 2022 12:39:08 GMT, Coleen Phillimore <cole...@openjdk.org> wrote:
>> Please review this simple conversion for the ProtectionDomainCacheTable from
>> Old Hashtable to ResourceHashtable. There are specific tests for this table
>> in test/hotspot/jtreg/runtime/Dictionary and
>> serviceability/dcmd/vm/DictionaryStatsTest.java.
>> Also tested with tier1-7.
>
> Coleen Phillimore has updated the pull request incrementally with one
> additional commit since the last revision:
>
> Fix comments, add assert.
I am utterly confused about why we need ProtectionDomainCacheTable at all. The
only interface between this class and the rest of the world is:
DictionaryEntry::add_protection_domain() {
WeakHandle obj =
ProtectionDomainCacheTable::add_if_absent(protection_domain);
// Additions and deletions hold the SystemDictionary_lock, readers are
lock-free
ProtectionDomainEntry* new_head = new ProtectionDomainEntry(obj, _pd_set);
}
(and there's code elsewhere for cleaning up this table, but that wouldn't be
necessary if no one calls `add_if_absent`!).
Why doesn't DictionaryEntry::add_protection_domain allocate the WeakHandle
itself?
I am looking at the JDK 8 code. It seems like ProtectionDomainCacheTable was
needed before we had WeakHandle, so we had to do all the reference management
by hand:
https://hg.openjdk.java.net/jdk8/jdk8/hotspot/file/87ee5ee27509/src/share/vm/classfile/dictionary.hpp#l137
But for today, is ProtectionDomainCacheTable a relic that can be thrown away?
-------------
PR: https://git.openjdk.org/jdk/pull/10043
