On Wed, 28 Apr 2021 00:29:23 GMT, Ioi Lam <ik...@openjdk.org> wrote:
>> src/hotspot/share/classfile/stringTable.cpp line 784:
>>
>>> 782: SharedStringIterator iter(f);
>>> 783: _shared_table.iterate(&iter);
>>> 784: }
>>
>> So with this change (somewhere below) do you no longer deduplicate strings
>> from the shared string table? ie
>>
>> // The CDS archive does not include the string deduplication table. Only the
>> string
>> // table is saved in the archive. The shared strings from CDS archive need
>> to be
>> // added to the string deduplication table before deduplication occurs. That
>> is
>> // done in the beginning of the StringDedupThread (see
>> StringDedupThread::do_deduplication()).
>> void StringDedupThread::deduplicate_shared_strings(StringDedupStat* stat) {
>> StringDedupSharedClosure sharedStringDedup(stat);
>> StringTable::shared_oops_do(&sharedStringDedup);
>> }
>> Asking @iklam to have a look then.
>
> If I understand correctly, we no longer need to add the entire set of shared
> strings into the dedup table.
>
>
> +// As a space optimization, when shared StringTable entries exist the shared
> +// part of the StringTable is also used as a source for byte arrays. This
> +// permits deduplication of strings against those shared entries without
> +// recording them in this table too.
> +class StringDedup::Table : AllStatic {
>
> ...
>
> +void StringDedup::Table::deduplicate(oop java_string) {
> + assert(java_lang_String::is_instance(java_string), "precondition");
> + _cur_stat.inc_inspected();
> + if ((StringTable::shared_entry_count() > 0) &&
> + try_deduplicate_shared(java_string)) {
> + return; // Done if deduplicated against shared
> StringTable.
Ioi is correct; we deduplicate "directly" against the shared string table
rather than adding the shared strings to the deduplication table.
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PR: https://git.openjdk.java.net/jdk/pull/3662
