[PR] Fix read throttling deadlock on Netty IO threads [bookkeeper]

["horizonzy (via GitHub)" <gi...@apache.org>]

horizonzy opened a new pull request, #4867:
URL: https://github.com/apache/bookkeeper/pull/4867

   ## Motivation
   
   Read throttling can block Netty IO/EventLoop threads when read permits are exhausted. Once the IO threads are blocked, the server may stop dispatching new requests and Netty write completions may not make progress, preventing read permits from being released.
   
   ## Changes
   
   - Move read permit acquisition out of `ReadEntryProcessor.create()` and related construction paths.
   - Acquire read permits when the read processor actually runs on the worker thread.
   - Avoid releasing read permits in rejected-execution paths where no permit has been acquired.
   - Add a regression test to verify request creation does not block Netty write completion when read permits are exhausted.
   
   ## Validation
   
   Added regression test fails on the old implementation and passes with this change:
   
   ```text
   testCreateDoesNotStarveWriteCompletionThatReleasesReadPermit


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Re: [PR] Fix read throttling deadlock on Netty IO threads [bookkeeper]

["StevenLuMT (via GitHub)" <gi...@apache.org>]

StevenLuMT commented on PR #4867:
URL: https://github.com/apache/bookkeeper/pull/4867#issuecomment-5364939136

   [ERROR] src/test/java/org/apache/bookkeeper/proto/ReadEntryProcessorTest.java:[23,15] (imports) UnusedImports: Unused import: org.junit.Assert.fail.
   [ERROR] src/test/java/org/apache/bookkeeper/proto/ReadEntryProcessorTest.java:[29,15] (imports) UnusedImports: Unused import: org.mockito.Mockito.never.
   [ERROR] src/test/java/org/apache/bookkeeper/proto/ReadEntryProcessorTest.java:[49,8] (imports) UnusedImports: Unused import: java.util.concurrent.TimeoutException.
   [ERROR] src/test/java/org/apache/bookkeeper/proto/ReadEntryProcessorTest.java:[208] (regexp) RegexpSingleline: Trailing whitespace
   
   @horizonzy 


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