RFR: 8323807: Async UL: Add a stalling mode to async UL [v8]

[David Holmes]

On Wed, 22 Jan 2025 10:15:37 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   David's suggestion plus hammering in that no messages are dropped
>
> src/hotspot/share/logging/logAsyncWriter.cpp line 114:
> 
>> 112:     _stalled_message = (Message*)ptr;
>> 113:     while (_stalled_message != nullptr) {
>> 114:       clocker.wait();
> 
> What ensures that the consumer side is notified and will process the stalled_message if the push_back above failed on an empty buffer?

I'm missing something here. If the message is too big even when the buffer is empty then how do we proceed? Stalling to wait for more space is not going to work. I assumed the message is already getting broken up into chunks somewhere else. ??

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PR Review Comment: https://git.openjdk.org/jdk/pull/22770#discussion_r1926306723