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Merge pull request #3638 from withchao/3.8.3-patch

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fix: resolve deadlock in cache eviction and improve GetBatch implementation
This commit is contained in:
chao 2025-12-12 15:46:38 +08:00 committed by GitHub
commit f4171a2c30
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5 changed files with 164 additions and 38 deletions
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19
pkg/localcache/cache.go
View File

@ -49,7 +49,7 @@ func New[V any](opts ...Option) Cache[V] {
if opt.expirationEvict {
return lru.NewExpirationLRU[string, V](opt.localSlotSize, opt.localSuccessTTL, opt.localFailedTTL, opt.target, c.onEvict)
} else {
return lru.NewLayLRU[string, V](opt.localSlotSize, opt.localSuccessTTL, opt.localFailedTTL, opt.target, c.onEvict)
return lru.NewLazyLRU[string, V](opt.localSlotSize, opt.localSuccessTTL, opt.localFailedTTL, opt.target, c.onEvict)
}
}
if opt.localSlotNum == 1 {
@ -72,12 +72,19 @@ type cache[V any] struct {
func (c *cache[V]) onEvict(key string, value V) {
if c.link != nil {
lks := c.link.Del(key)
for k := range lks {
if key != k { // prevent deadlock
c.local.Del(k)
// Do not delete other keys while the underlying LRU still holds its lock;
// defer linked deletions to avoid re-entering the same slot and deadlocking.
if lks := c.link.Del(key); len(lks) > 0 {
go c.delLinked(key, lks)
}
}
}
func (c *cache[V]) delLinked(src string, keys map[string]struct{}) {
for k := range keys {
if src != k {
c.local.Del(k)
}
}
}
@ -103,7 +110,7 @@ func (c *cache[V]) Get(ctx context.Context, key string, fetch func(ctx context.C
func (c *cache[V]) GetLink(ctx context.Context, key string, fetch func(ctx context.Context) (V, error), link ...string) (V, error) {
if c.local != nil {
return c.local.Get(key, func() (V, error) {
if len(link) > 0 {
if len(link) > 0 && c.link != nil {
c.link.Link(key, link...)
}
return fetch(ctx)

67
pkg/localcache/cache_test.go
View File

@ -22,6 +22,8 @@ import (
"sync/atomic"
"testing"
"time"
"github.com/openimsdk/open-im-server/v3/pkg/localcache/lru"
)
func TestName(t *testing.T) {
@ -91,3 +93,68 @@ func TestName(t *testing.T) {
t.Log("del", del.Load())
// 137.35s
}
// Test deadlock scenario when eviction callback deletes a linked key that hashes to the same slot.
func TestCacheEvictDeadlock(t *testing.T) {
ctx := context.Background()
c := New[string](WithLocalSlotNum(1), WithLocalSlotSize(1), WithLazy())
if _, err := c.GetLink(ctx, "k1", func(ctx context.Context) (string, error) {
return "v1", nil
}, "k2"); err != nil {
t.Fatalf("seed cache failed: %v", err)
}
done := make(chan struct{})
go func() {
defer close(done)
_, _ = c.GetLink(ctx, "k2", func(ctx context.Context) (string, error) {
return "v2", nil
}, "k1")
}()
select {
case <-done:
// expected to finish quickly; current implementation deadlocks here.
case <-time.After(time.Second):
t.Fatal("GetLink deadlocked during eviction of linked key")
}
}
func TestExpirationLRUGetBatch(t *testing.T) {
l := lru.NewExpirationLRU[string, string](2, time.Minute, time.Second*5, EmptyTarget{}, nil)
keys := []string{"a", "b"}
values, err := l.GetBatch(keys, func(keys []string) (map[string]string, error) {
res := make(map[string]string)
for _, k := range keys {
res[k] = k + "_v"
}
return res, nil
})
if err != nil {
t.Fatalf("unexpected error: %v", err)
}
if len(values) != len(keys) {
t.Fatalf("expected %d values, got %d", len(keys), len(values))
}
for _, k := range keys {
if v, ok := values[k]; !ok || v != k+"_v" {
t.Fatalf("unexpected value for %s: %q, ok=%v", k, v, ok)
}
}
// second batch should hit cache
values, err = l.GetBatch(keys, func(keys []string) (map[string]string, error) {
t.Fatalf("should not fetch on cache hit")
return nil, nil
})
if err != nil {
t.Fatalf("unexpected error on cache hit: %v", err)
}
for _, k := range keys {
if v, ok := values[k]; !ok || v != k+"_v" {
t.Fatalf("unexpected cached value for %s: %q, ok=%v", k, v, ok)
}
}
}

49
pkg/localcache/lru/lru_expiration.go
View File

@ -52,8 +52,53 @@ type ExpirationLRU[K comparable, V any] struct {
}
func (x *ExpirationLRU[K, V]) GetBatch(keys []K, fetch func(keys []K) (map[K]V, error)) (map[K]V, error) {
//TODO implement me
panic("implement me")
var (
err error
results = make(map[K]V)
misses = make([]K, 0, len(keys))
)
for _, key := range keys {
x.lock.Lock()
v, ok := x.core.Get(key)
x.lock.Unlock()
if ok {
x.target.IncrGetHit()
v.lock.RLock()
results[key] = v.value
if v.err != nil && err == nil {
err = v.err
}
v.lock.RUnlock()
continue
}
misses = append(misses, key)
}
if len(misses) == 0 {
return results, err
}
fetchValues, fetchErr := fetch(misses)
if fetchErr != nil && err == nil {
err = fetchErr
}
for key, val := range fetchValues {
results[key] = val
if fetchErr != nil {
x.target.IncrGetFailed()
continue
}
x.target.IncrGetSuccess()
item := &expirationLruItem[V]{value: val}
x.lock.Lock()
x.core.Add(key, item)
x.lock.Unlock()
}
// any keys not returned from fetch remain absent (no cache write)
return results, err
}
func (x *ExpirationLRU[K, V]) Get(key K, fetch func() (V, error)) (V, error) {

56
pkg/localcache/lru/lru_lazy.go
View File

@ -21,25 +21,25 @@ import (
"github.com/hashicorp/golang-lru/v2/simplelru"
)
type layLruItem[V any] struct {
type lazyLruItem[V any] struct {
lock sync.Mutex
expires int64
err error
value V
}
func NewLayLRU[K comparable, V any](size int, successTTL, failedTTL time.Duration, target Target, onEvict EvictCallback[K, V]) *LayLRU[K, V] {
var cb simplelru.EvictCallback[K, *layLruItem[V]]
func NewLazyLRU[K comparable, V any](size int, successTTL, failedTTL time.Duration, target Target, onEvict EvictCallback[K, V]) *LazyLRU[K, V] {
var cb simplelru.EvictCallback[K, *lazyLruItem[V]]
if onEvict != nil {
cb = func(key K, value *layLruItem[V]) {
cb = func(key K, value *lazyLruItem[V]) {
onEvict(key, value.value)
}
}
core, err := simplelru.NewLRU[K, *layLruItem[V]](size, cb)
core, err := simplelru.NewLRU[K, *lazyLruItem[V]](size, cb)
if err != nil {
panic(err)
}
return &LayLRU[K, V]{
return &LazyLRU[K, V]{
core: core,
successTTL: successTTL,
failedTTL: failedTTL,
@ -47,15 +47,15 @@ func NewLayLRU[K comparable, V any](size int, successTTL, failedTTL time.Duratio
}
}
type LayLRU[K comparable, V any] struct {
type LazyLRU[K comparable, V any] struct {
lock sync.Mutex
core *simplelru.LRU[K, *layLruItem[V]]
core *simplelru.LRU[K, *lazyLruItem[V]]
successTTL time.Duration
failedTTL time.Duration
target Target
}
func (x *LayLRU[K, V]) Get(key K, fetch func() (V, error)) (V, error) {
func (x *LazyLRU[K, V]) Get(key K, fetch func() (V, error)) (V, error) {
x.lock.Lock()
v, ok := x.core.Get(key)
if ok {
@ -68,7 +68,7 @@ func (x *LayLRU[K, V]) Get(key K, fetch func() (V, error)) (V, error) {
return value, err
}
} else {
v = &layLruItem[V]{}
v = &lazyLruItem[V]{}
x.core.Add(key, v)
v.lock.Lock()
x.lock.Unlock()
@ -88,15 +88,15 @@ func (x *LayLRU[K, V]) Get(key K, fetch func() (V, error)) (V, error) {
return v.value, v.err
}
func (x *LayLRU[K, V]) GetBatch(keys []K, fetch func(keys []K) (map[K]V, error)) (map[K]V, error) {
func (x *LazyLRU[K, V]) GetBatch(keys []K, fetch func(keys []K) (map[K]V, error)) (map[K]V, error) {
var (
err error
once sync.Once
)
res := make(map[K]V)
queries := make([]K, 0)
setVs := make(map[K]*layLruItem[V])
queries := make([]K, 0, len(keys))
for _, key := range keys {
x.lock.Lock()
v, ok := x.core.Get(key)
@ -118,14 +118,20 @@ func (x *LayLRU[K, V]) GetBatch(keys []K, fetch func(keys []K) (map[K]V, error))
}
queries = append(queries, key)
}
values, err1 := fetch(queries)
if err1 != nil {
if len(queries) == 0 {
return res, err
}
values, fetchErr := fetch(queries)
if fetchErr != nil {
once.Do(func() {
err = err1
err = fetchErr
})
}
for key, val := range values {
v := &layLruItem[V]{}
v := &lazyLruItem[V]{}
v.value = val
if err == nil {
@ -135,7 +141,7 @@ func (x *LayLRU[K, V]) GetBatch(keys []K, fetch func(keys []K) (map[K]V, error))
v.expires = time.Now().Add(x.failedTTL).UnixMilli()
x.target.IncrGetFailed()
}
setVs[key] = v
x.lock.Lock()
x.core.Add(key, v)
x.lock.Unlock()
@ -145,29 +151,29 @@ func (x *LayLRU[K, V]) GetBatch(keys []K, fetch func(keys []K) (map[K]V, error))
return res, err
}
//func (x *LayLRU[K, V]) Has(key K) bool {
//func (x *LazyLRU[K, V]) Has(key K) bool {
// x.lock.Lock()
// defer x.lock.Unlock()
// return x.core.Contains(key)
//}
func (x *LayLRU[K, V]) Set(key K, value V) {
func (x *LazyLRU[K, V]) Set(key K, value V) {
x.lock.Lock()
defer x.lock.Unlock()
x.core.Add(key, &layLruItem[V]{value: value, expires: time.Now().Add(x.successTTL).UnixMilli()})
x.core.Add(key, &lazyLruItem[V]{value: value, expires: time.Now().Add(x.successTTL).UnixMilli()})
}
func (x *LayLRU[K, V]) SetHas(key K, value V) bool {
func (x *LazyLRU[K, V]) SetHas(key K, value V) bool {
x.lock.Lock()
defer x.lock.Unlock()
if x.core.Contains(key) {
x.core.Add(key, &layLruItem[V]{value: value, expires: time.Now().Add(x.successTTL).UnixMilli()})
x.core.Add(key, &lazyLruItem[V]{value: value, expires: time.Now().Add(x.successTTL).UnixMilli()})
return true
}
return false
}
func (x *LayLRU[K, V]) Del(key K) bool {
func (x *LazyLRU[K, V]) Del(key K) bool {
x.lock.Lock()
ok := x.core.Remove(key)
x.lock.Unlock()
@ -179,6 +185,6 @@ func (x *LayLRU[K, V]) Del(key K) bool {
return ok
}
func (x *LayLRU[K, V]) Stop() {
func (x *LazyLRU[K, V]) Stop() {
}

9
pkg/rpccache/online.go
View File

@ -3,15 +3,16 @@ package rpccache
import (
"context"
"fmt"
"github.com/openimsdk/open-im-server/v3/pkg/rpcli"
"github.com/openimsdk/protocol/constant"
"github.com/openimsdk/protocol/user"
"math/rand"
"strconv"
"sync"
"sync/atomic"
"time"
"github.com/openimsdk/open-im-server/v3/pkg/rpcli"
"github.com/openimsdk/protocol/constant"
"github.com/openimsdk/protocol/user"
"github.com/openimsdk/open-im-server/v3/pkg/common/storage/cache/cachekey"
"github.com/openimsdk/open-im-server/v3/pkg/localcache"
"github.com/openimsdk/open-im-server/v3/pkg/localcache/lru"
@ -46,7 +47,7 @@ func NewOnlineCache(client *rpcli.UserClient, group *GroupLocalCache, rdb redis.
case false:
log.ZDebug(ctx, "fullUserCache is false")
x.lruCache = lru.NewSlotLRU(1024, localcache.LRUStringHash, func() lru.LRU[string, []int32] {
return lru.NewLayLRU[string, []int32](2048, cachekey.OnlineExpire/2, time.Second*3, localcache.EmptyTarget{}, func(key string, value []int32) {})
return lru.NewLazyLRU[string, []int32](2048, cachekey.OnlineExpire/2, time.Second*3, localcache.EmptyTarget{}, func(key string, value []int32) {})
})
x.CurrentPhase.Store(DoSubscribeOver)
x.Cond.Broadcast()