[#1689] shard: Use single qos.Limiter instance for shard and writecache

Before fix shard and writecache used the same instance of qos.Limiter.
In case of SIGHUP signal shard was closing qos.Limiter, but didn't
update writecache's pointer.

Now shard uses atomic pointer to qos.Limiter and shares it with writecache.
On SIGHUP shard updates atomic pointer value and closes old qos.Limiter.

Change-Id: Ic2ab62441d3872e71c5771f54d070e0ca48fe375
Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

cmd/frostfs-node/config.go

@@ -920,7 +920,6 @@ func (c *cfg) getWriteCacheOpts(shCfg shardCfg) []writecache.Option {
 			writecache.WithMaxCacheCount(wcRead.countLimit),
 			writecache.WithNoSync(wcRead.noSync),
 			writecache.WithLogger(c.log.WithTag(logger.TagWriteCache)),
-			writecache.WithQoSLimiter(shCfg.limiter),
 		)
 	}
 	return writeCacheOpts

pkg/local_object_storage/shard/control.go

@@ -452,11 +452,20 @@ func (s *Shard) Reload(ctx context.Context, opts ...Option) error {
 			return err
 		}
 	}
-	if c.opsLimiter != nil {
-		s.opsLimiter.Close()
-		s.opsLimiter = c.opsLimiter
+	if err := s.setMode(ctx, c.info.Mode); err != nil {
+		return err
+	}
+	s.reloadOpsLimiter(&c)
+
+	return nil
+}
+
+func (s *Shard) reloadOpsLimiter(c *cfg) {
+	if c.configOpsLimiter != nil {
+		old := s.opsLimiter.ptr.Swap(&qosLimiterHolder{Limiter: c.configOpsLimiter})
+		old.Close()
+		s.opsLimiter.SetParentID(s.info.ID.String())
 	}
-	return s.setMode(ctx, c.info.Mode)
 }
 
 func (s *Shard) lockExclusive() func() {

pkg/local_object_storage/shard/shard.go

@@ -39,6 +39,8 @@ type Shard struct {
 
 	rb *rebuilder
 
+	opsLimiter *atomicOpsLimiter
+
 	gcCancel             atomic.Value
 	setModeRequested     atomic.Bool
 	writecacheSealCancel atomic.Pointer[writecacheSealCanceler]
@@ -100,7 +102,7 @@ type cfg struct {
 
 	containerInfo container.InfoProvider
 
-	opsLimiter qos.Limiter
+	configOpsLimiter qos.Limiter
 }
 
 func defaultCfg() *cfg {
@@ -112,7 +114,7 @@ func defaultCfg() *cfg {
 		zeroSizeContainersCallback:  func(context.Context, []cid.ID) {},
 		zeroCountContainersCallback: func(context.Context, []cid.ID) {},
 		metricsWriter:               noopMetrics{},
-		opsLimiter:                  qos.NewNoopLimiter(),
+		configOpsLimiter:            qos.NewNoopLimiter(),
 	}
 }
 
@@ -132,6 +134,7 @@ func New(opts ...Option) *Shard {
 		blobStor:   bs,
 		metaBase:   mb,
 		tsSource:   c.tsSource,
+		opsLimiter: newAtomicOpsLimiter(c.configOpsLimiter),
 	}
 
 	reportFunc := func(ctx context.Context, msg string, err error) {
@@ -145,7 +148,8 @@ func New(opts ...Option) *Shard {
 			append(c.writeCacheOpts,
 				writecache.WithReportErrorFunc(reportFunc),
 				writecache.WithBlobstor(bs),
-				writecache.WithMetabase(mb))...)
+				writecache.WithMetabase(mb),
+				writecache.WithQoSLimiter(s.opsLimiter))...)
 		s.writeCache.GetMetrics().SetPath(s.writeCache.DumpInfo().Path)
 	}
 
@@ -374,7 +378,7 @@ func WithContainerInfoProvider(containerInfo container.InfoProvider) Option {
 
 func WithLimiter(l qos.Limiter) Option {
 	return func(c *cfg) {
-		c.opsLimiter = l
+		c.configOpsLimiter = l
 	}
 }
 
@@ -520,3 +524,39 @@ func (s *Shard) SetEvacuationInProgress(val bool) {
 	s.info.EvacuationInProgress = val
 	s.metricsWriter.SetEvacuationInProgress(val)
 }
+
+var _ qos.Limiter = &atomicOpsLimiter{}
+
+func newAtomicOpsLimiter(l qos.Limiter) *atomicOpsLimiter {
+	result := &atomicOpsLimiter{}
+	result.ptr.Store(&qosLimiterHolder{Limiter: l})
+	return result
+}
+
+type atomicOpsLimiter struct {
+	ptr atomic.Pointer[qosLimiterHolder]
+}
+
+func (a *atomicOpsLimiter) Close() {
+	a.ptr.Load().Close()
+}
+
+func (a *atomicOpsLimiter) ReadRequest(ctx context.Context) (qos.ReleaseFunc, error) {
+	return a.ptr.Load().ReadRequest(ctx)
+}
+
+func (a *atomicOpsLimiter) SetMetrics(m qos.Metrics) {
+	a.ptr.Load().SetMetrics(m)
+}
+
+func (a *atomicOpsLimiter) SetParentID(id string) {
+	a.ptr.Load().SetParentID(id)
+}
+
+func (a *atomicOpsLimiter) WriteRequest(ctx context.Context) (qos.ReleaseFunc, error) {
+	return a.ptr.Load().WriteRequest(ctx)
+}
+
+type qosLimiterHolder struct {
+	qos.Limiter
+}