ydb/library/cpp/yt/threading, branch oidc-1.2.4

YT-24537: Prioritize writers in TReaderWriterSpinLock, rename old version to TWriterStarvingRWLock

2025-04-17T11:47:23Z

Previously, it was possible that `TReaderWriterSpinLock` wouldn't let the writer through if there's a steady flow of readers. This change addresses that by: 1. Prioritizing writers inside the spinlock by adding an additional `WriterReady` flag that writers set on arrival. This flag doesn't allow any readers to come through. 2. Adding the proper tests to verify this functionality, as well as spinlock's behaviour under forks. 3. Clarifying the documentation about spinlock guarantees 4. Adding a TLA+ model, formally specifying and verifying the guarantees of the new spinlock. 5. Renaming the old lock to `TWriterStarvingRWSpinLock`, and replacing all usages inside YT with the new version (renaming all usages outside of YT to the WriterStarving version). This is a second attempt of REVIEW: 8233768, the first one was rolled back as it lead to deadlocks in user code with reentrant reader locks: the case of `AcquireReader(thread0) -> AcquireWriter(thread1) -> AcquireReader(thread0)` is a deadlock, as `thread0` will not be able to acquire the lock (for the second time) before `thread1` frees writer lock, and `thread1` will not be able to acquire writer lock before the reader lock will be released by `thread0`, which won't happen until `thread0` acquires the lock for the second time. See/for more context and a real example of such situation. Analogous problem can happen with fibers: this is why you shouldn't allow context switches under the lock. Wondering why this ugly name `WriterStarvingRWSpinLock` appeared in your beautiful code? No worries, if you are **sure** that you don't use reentrant locks or fiber switches under the lock, you can freely replace your usage with the new `ReaderWriterSpinLock`. The replacement is drop-in. [nodiff:caesar] commit_hash:97683f854defca00cc283f5a2a10a1730b3c9174

Revert commit rXXXXXX, YT-24537: Prioritize writers in TReaderWriterSpinLock

2025-04-15T16:53:08Z

It turns out, RWSpinLock previously accidentally supported recursive AcquireReaders, and this property was broken with the change. commit_hash:f996e7b52ef8b3d37118034530a094af0efbe435

YT-24537: Prioritize writers in TReaderWriterSpinLock

2025-04-10T12:57:08Z

commit_hash:94fee5363799655628bd7e2c144a7869a9d89002

Move libyqlplugin.so to yt

2025-02-05T17:40:36Z

Приедет в ytsaurus: Приедет в `/contrib/ydb/` Проверка, что в github ydb ничего не сломается: commit_hash:73ab1b4a3245322afc9fc6e9d71424ad07106477

Typos

2025-01-16T08:39:38Z

commit_hash:afeeeea3c2cbdec0ddeed0fea5f88df9d8575f8b

Fix babenko issues of rXXXXXX

2024-11-14T09:22:27Z

[nodiff:caesar] commit_hash:93eef00a7132e68e727aa1f4028616db6522d03c

Move atomic object to library/cpp/yt/threading

2024-10-14T14:40:51Z

[nodiff:caesar] commit_hash:446e45e0378f6b2cb31d85bcc3e4516efbdfe5a7

YT-21233: Split error into error and stripped_error to rid the latter of deps on global variables

2024-08-15T15:44:19Z

What happened: 1. error contents has been split into stripped_error and error. stripped_error contains the error itself (with attributes for now) and macros; error contains stripped_error and some extensions, namely, functions to get fiberId, hostname and traceid/spanid and all functions used to (de-)serialize error. This means that you cannot print error if you only include stripped_error, therefore you are likely to still require the entire error.h at the moment. 2. Mechanic for gathering origin attributes has been moved to newly created library/cpp/yt/error thus having no dependency on fibers, net or tracing. stripped_error uses these attributes as extendable semi-erased (meaning, you still would have to add a field and recompile the entire thing, but you don't have to introduce an extra dependency) storage for a bunch of attributes 3. Parsing of said attributes is done in error file (and not stripped_error). P.S. So far the plan is to eventually move stripped_error (once dependency on core/ytree/attributes is eliminated) without any actual change to dependency graph of anything outside of core (e.g. you would still have to include misc/error.h to use it). Next step would be re-teaching the error how to print, which would move some more methods from core to the standalone module. After that one could finally depend on the error itself and not the entire core. Annotations: [nodiff:caesar] 66615172181355821241d2e5f8e4a0f15e0ea791

Throw on error in TNotificationHandle::TNotificationHandle instead of crashing

2024-08-11T07:50:18Z

4356fc70f6d9ceec9f94b1879f49e27f3fee4342

Return to the use of NThreading::TSpinLock

2024-06-11T07:16:48Z

4792c7769dba84e38c0d981714741114add571d3