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reader_concurrency_semaphore: do_wait_admission(): remove dumping diagnostics

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The commit b39ca29b3c introduced detection of admission-waiter
anomaly and dumps permit diagnostics as soon as the semaphore did
not admit readers even though it could.

Later on, the commit bf3d0b3543 introduces the optimization where
the admission check is moved to the fiber processing the _read_list.
Since the semaphore no longer admits readers as soon as it can,
dumping diagnostic errors is not necessary as the situation is not
abnormal.

Closes scylladb/scylladb#22344
This commit is contained in:
Łukasz Paszkowski
2025-01-16 09:54:05 +01:00
committed by Avi Kivity
parent 955ac1b7b7
commit aad46bd6f3
1 changed files with 4 additions and 5 deletions
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9
reader_concurrency_semaphore.cc
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@@ -1460,11 +1460,10 @@ future<> reader_concurrency_semaphore::do_wait_admission(reader_permit::impl& pe
if (admit != can_admit::yes || !_wait_list.empty()) {
auto fut = enqueue_waiter(permit, wait_on::admission);
if (admit == can_admit::yes && !_wait_list.empty()) {
// This is a contradiction: the semaphore could admit waiters yet it has waiters.
// Normally, the semaphore should admit waiters as soon as it can.
// So at any point in time, there should either be no waiters, or it
// shouldn't be able to admit new reads. Otherwise something went wrong.
maybe_dump_reader_permit_diagnostics(*this, "semaphore could admit new reads yet there are waiters", nullptr);
// Enters the case where the semaphore can admit waiters yet it has waiters.
// Hence, wake the execution loop to process the waiters. Since readers are
// no longer admitted as soon as they can, the resource release could be delayed
// as well.
maybe_wake_execution_loop();
} else if (admit == can_admit::maybe) {
tracing::trace(permit.trace_state(), "[reader concurrency semaphore {}] evicting inactive reads in the background to free up resources", _name);