RFR: 8308310: HttpClient: Avoid logging or locking from within synchronized blocks [v8]

[Jaikiran Pai]

On Tue, 23 May 2023 15:11:10 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> Please find here a change that revisits usage of monitors in the HttpClient.
>> 
>> With Virtual Threads now part of the platform it should be possible to pass a newVirtualThreadPerTaskExecutor to the HttpClient. Logging, when enabled, and when called from a synchronized block, can cause the carrier thread to get pinned in case of contention when printing through the underlying PrintStream.
>> 
>> This change aims at avoiding situations where the carrier threads might get pinned.
>
> Daniel Fuchs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 11 commits:
> 
>  - Merge branch 'master' into HttpClient-Logging-8308310
>  - Merge branch 'master' into HttpClient-Logging-8308310
>  - Fix whitespace
>  - make stateLock final
>  - Add debug traces to ExpectContinueTest.java
>  - failedRef should be final
>  - Align parameters
>  - Update src/java.net.http/share/classes/jdk/internal/net/http/Http1Response.java
>    
>    Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>
>  - Update src/java.net.http/share/classes/jdk/internal/net/http/ConnectionPool.java
>    
>    Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>
>  - Update test/jdk/java/net/httpclient/AuthFilterCacheTest.java
>    
>    Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>
>  - ... and 1 more: https://git.openjdk.org/jdk/compare/c0c4d771...c5d2f1f2

src/java.net.http/share/classes/jdk/internal/net/http/ConnectionPool.java line 476:

> 474:         }
> 475: 
> 476:         // should only be called while holding the ConnectionPool stateLock.

Hello Daniel, all these methods which say a lock needs to be held when they are called, should we add a `assert stateLock.isHeldByCurrentThread();` to make it verifiable? I understand we didn't have a similar assert when the comment said the method needs to be called while holding the monitor, but since we are changing this part now, perhaps we can add those asserts?

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PR Review Comment: https://git.openjdk.org/jdk/pull/14038#discussion_r1203869893