mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-24 07:10:20 +00:00
f60a07ae82
some of the kubernetes independent packages are moved out of the tree to new projects. Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
59 lines
1.5 KiB
Go
59 lines
1.5 KiB
Go
/*
|
|
Copyright 2018 The Kubernetes Authors.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package keymutex
|
|
|
|
import (
|
|
"hash/fnv"
|
|
"runtime"
|
|
"sync"
|
|
)
|
|
|
|
// NewHashed returns a new instance of KeyMutex which hashes arbitrary keys to
|
|
// a fixed set of locks. `n` specifies number of locks, if n <= 0, we use
|
|
// number of cpus.
|
|
// Note that because it uses fixed set of locks, different keys may share same
|
|
// lock, so it's possible to wait on same lock.
|
|
func NewHashed(n int) KeyMutex {
|
|
if n <= 0 {
|
|
n = runtime.NumCPU()
|
|
}
|
|
return &hashedKeyMutex{
|
|
mutexes: make([]sync.Mutex, n),
|
|
}
|
|
}
|
|
|
|
type hashedKeyMutex struct {
|
|
mutexes []sync.Mutex
|
|
}
|
|
|
|
// Acquires a lock associated with the specified ID.
|
|
func (km *hashedKeyMutex) LockKey(id string) {
|
|
km.mutexes[km.hash(id)%uint32(len(km.mutexes))].Lock()
|
|
}
|
|
|
|
// Releases the lock associated with the specified ID.
|
|
func (km *hashedKeyMutex) UnlockKey(id string) error {
|
|
km.mutexes[km.hash(id)%uint32(len(km.mutexes))].Unlock()
|
|
return nil
|
|
}
|
|
|
|
func (km *hashedKeyMutex) hash(id string) uint32 {
|
|
h := fnv.New32a()
|
|
h.Write([]byte(id))
|
|
return h.Sum32()
|
|
}
|