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TestAcquire_Low_Success

go.temporal.io/server/common/locks/TestPrioritySemaphoreSuite/TestAcquire_Low_Success

Package
go.temporal.io/server/common/locks
Suite / test hierarchy
TestPrioritySemaphoreSuite/TestAcquire_Low_Success
Test
TestAcquire_Low_Success
Introduced at
TestAcquire_Low_Success, TestAcquire_High_Success Test frontier
Covered ranges
14
Covered lines
50
Covered files
1

Co-introduced tests

1 other test enter at the same concept.

Covered source

Expand a file to inspect source; the > gutter marks covered lines.

go.temporal.io/server/common/locks/priority_semaphore_impl.go 50 covered LOC · 14 ranges

Open complete file

67 // maximum combined weight for concurrent access, capable of handling multiple priority levels.
68 // Most of the logic is taken directly from golang's semaphore.Weighted.
69 > func NewPrioritySemaphore(n int) *PrioritySemaphoreImpl { priority_semaphore_impl.go
70 > waitLists := make([]*list.List, NumPriorities)
71 > for i := range waitLists {
72 > waitLists[i] = list.New()
73 > }
74 > return &PrioritySemaphoreImpl{
75 > size: n,
76 > waitLists: waitLists,
77 > }
78 }
79
81 // are available or ctx is done. On success, returns nil. On failure, returns
82 // ctx.Err() and leaves the semaphore unchanged.
83 > func (s *PrioritySemaphoreImpl) Acquire(ctx context.Context, priority Priority, n int) error { priority_semaphore_impl.go
84 > if priority >= NumPriorities {
85 // nolint:forbidigo
86 panic(fmt.Sprintf("semaphore: invalid priority %v, priority must be less than %v", priority, NumPriorities))
87 }
88
89 > done := ctx.Done() priority_semaphore_impl.go
90 >
91 > s.mu.Lock()
92 > select {
93 case <-done:
94 // ctx becoming done has "happened before" acquiring the semaphore,
98 s.mu.Unlock()
99 return ctx.Err()
100 > default: priority_semaphore_impl.go
101 }
102 // Check if acquisition can proceed without waiting
103 > if s.size-s.cur >= n && s.noWaiters(priority) { priority_semaphore_impl.go
104 > // Since we hold s.mu and haven't synchronized since checking done, if priority_semaphore_impl.go
105 > // ctx becomes done before we return here, it becoming done must have
106 > // "happened concurrently" with this call - it cannot "happen before"
107 > // we return in this branch. So, we're ok to always acquire here.
108 > s.cur += n
109 > s.mu.Unlock()
110 > return nil
111 > }
112
113 if n > s.size {
158 // TryAcquire acquires the semaphore with a weight of n without blocking.
159 // On success, returns true. On failure, returns false and leaves the semaphore unchanged.
160 > func (s *PrioritySemaphoreImpl) TryAcquire(priority Priority, n int) bool { priority_semaphore_impl.go
161 > if priority >= NumPriorities {
162 // nolint:forbidigo
163 panic(fmt.Sprintf("semaphore: invalid priority %v, priority must be less than %v", priority, NumPriorities))
164 }
165
166 > s.mu.Lock() priority_semaphore_impl.go
167 > defer s.mu.Unlock()
168 > if s.size-s.cur >= n && s.noWaiters(priority) {
169 > s.cur += n
170 > return true
171 > }
172 > return false priority_semaphore_impl.go
173 }
174
175 > func (s *PrioritySemaphoreImpl) Release(n int) { priority_semaphore_impl.go
176 > s.mu.Lock()
177 > defer s.mu.Unlock()
178 > s.cur -= n
179 > if s.cur < 0 {
180 s.mu.Unlock()
181 panic("semaphore: released more than held")
182 }
183 > s.notifyWaiters() priority_semaphore_impl.go
184 }
185
186 > func (s *PrioritySemaphoreImpl) notifyWaiters() { priority_semaphore_impl.go
187 > for _, l := range s.waitLists {
188 > for {
189 > next := l.Front()
190 > if next == nil {
191 > break // No more waiters blocked.
192 }
193
219
220 // noWaiters returns if there is no waiter that has priority higher or equal to lowestPriority.
221 > func (s *PrioritySemaphoreImpl) noWaiters(lowestPriority Priority) bool { priority_semaphore_impl.go
222 > for _, l := range s.waitLists[:lowestPriority+1] {
223 > if l.Len() > 0 {
224 return false
225 }
226 }
227 > return true priority_semaphore_impl.go
228 }