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storelimit: fix datarace from getOrCreateStoreLimit #8254

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merged 5 commits into from
Jun 5, 2024
Merged

storelimit: fix datarace from getOrCreateStoreLimit #8254

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c1fe958
add test
lhy1024 Jun 4, 2024
977c2bb
storelimit: fix datarace on reset
lhy1024 Jun 4, 2024
bcc48dd
rename
lhy1024 Jun 5, 2024
4185a77
reduce test time
lhy1024 Jun 5, 2024
0effc76
Merge branch 'master' into fix-datarace4
lhy1024 Jun 5, 2024
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20 changes: 17 additions & 3 deletions pkg/core/storelimit/store_limit.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@ package storelimit
import (
"github.com/tikv/pd/pkg/core/constant"
"github.com/tikv/pd/pkg/ratelimit"
"github.com/tikv/pd/pkg/utils/syncutil"
)

const (
Expand Down Expand Up @@ -106,7 +107,7 @@ func (l *StoreRateLimit) Rate(typ Type) float64 {
if l.limits[typ] == nil {
return 0.0
}
return l.limits[typ].ratePerSec
return l.limits[typ].GetRatePerSec()
}

// Take takes count tokens from the bucket without blocking.
Expand All @@ -128,12 +129,15 @@ func (l *StoreRateLimit) Reset(rate float64, typ Type) {

// limit the operators of a store
type limit struct {
limiter *ratelimit.RateLimiter
ratePerSec float64
limiter *ratelimit.RateLimiter
ratePerSecMutex syncutil.RWMutex
ratePerSec float64
}

// Reset resets the rate limit.
func (l *limit) Reset(ratePerSec float64) {
l.ratePerSecMutex.Lock()
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Will it happen in the current code or just in your testing code?

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I think datarace can happen in the current code, we call getOrCreateStoreLimit in many places now, like in AddOperator or tryAddOperators, where we call ExceedStoreLimit to check the limit.

If the getOrCreateStoreLimit enters the ResetStoreLimit branch, then datarace is possible.

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And just like the test I built, this scenario is also possible to datarace if we set storelimit when other code calls getOrCreateStoreLimit.

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seems it is caused by #8032

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seems it is caused by #8032

sure, this test will fail since #8032

defer l.ratePerSecMutex.Unlock()
if l.ratePerSec == ratePerSec {
return
}
Expand All @@ -155,6 +159,8 @@ func (l *limit) Reset(ratePerSec float64) {
// Available returns the number of available tokens
// It returns true if the rate per second is zero.
func (l *limit) Available(n int64) bool {
l.ratePerSecMutex.RLock()
defer l.ratePerSecMutex.RUnlock()
if l.ratePerSec == 0 {
return true
}
Expand All @@ -164,8 +170,16 @@ func (l *limit) Available(n int64) bool {

// Take takes count tokens from the bucket without blocking.
func (l *limit) Take(count int64) bool {
l.ratePerSecMutex.RLock()
defer l.ratePerSecMutex.RUnlock()
if l.ratePerSec == 0 {
return true
}
return l.limiter.AllowN(int(count))
}

func (l *limit) GetRatePerSec() float64 {
l.ratePerSecMutex.RLock()
defer l.ratePerSecMutex.RUnlock()
return l.ratePerSec
}
37 changes: 37 additions & 0 deletions pkg/schedule/operator/operator_controller_test.go
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Expand Up @@ -955,3 +955,40 @@ func (suite *operatorControllerTestSuite) TestInvalidStoreId() {
// Although store 3 does not exist in PD, PD can also send op to TiKV.
re.Equal(pdpb.OperatorStatus_RUNNING, oc.GetOperatorStatus(1).Status)
}

func TestConcurrentAddOperatorAndSetStoreLimit(t *testing.T) {
re := require.New(t)
opt := mockconfig.NewTestOptions()
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
tc := mockcluster.NewCluster(ctx, opt)
stream := hbstream.NewTestHeartbeatStreams(ctx, tc.ID, tc, false /* no need to run */)
oc := NewController(ctx, tc.GetBasicCluster(), tc.GetSharedConfig(), stream)

regionNum := 1000
limit := 1600.0
storeID := uint64(2)
for i := 1; i < 4; i++ {
tc.AddRegionStore(uint64(i), regionNum)
tc.SetStoreLimit(uint64(i), storelimit.AddPeer, limit)
}
for i := 1; i <= regionNum; i++ {
tc.AddLeaderRegion(uint64(i), 1, 3, 4)
}

// Add operator and set store limit concurrently
var wg sync.WaitGroup
for i := 1; i < 10; i++ {
wg.Add(1)
go func(i uint64) {
defer wg.Done()
for j := 1; j < 10; j++ {
regionID := uint64(j) + i*100
op := NewTestOperator(regionID, tc.GetRegion(regionID).GetRegionEpoch(), OpRegion, AddPeer{ToStore: storeID, PeerID: regionID})
re.True(oc.AddOperator(op))
tc.SetStoreLimit(storeID, storelimit.AddPeer, limit-float64(j)) // every goroutine set a different limit
}
}(uint64(i))
}
wg.Wait()
}