khenaidoo | 2672188 | 2021-08-11 17:42:52 -0400 | [diff] [blame] | 1 | // Copyright 2016 The etcd Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package etcdserver |
| 16 | |
| 17 | import pb "github.com/coreos/etcd/etcdserver/etcdserverpb" |
| 18 | |
| 19 | const ( |
| 20 | // DefaultQuotaBytes is the number of bytes the backend Size may |
| 21 | // consume before exceeding the space quota. |
| 22 | DefaultQuotaBytes = int64(2 * 1024 * 1024 * 1024) // 2GB |
| 23 | // MaxQuotaBytes is the maximum number of bytes suggested for a backend |
| 24 | // quota. A larger quota may lead to degraded performance. |
| 25 | MaxQuotaBytes = int64(8 * 1024 * 1024 * 1024) // 8GB |
| 26 | ) |
| 27 | |
| 28 | // Quota represents an arbitrary quota against arbitrary requests. Each request |
| 29 | // costs some charge; if there is not enough remaining charge, then there are |
| 30 | // too few resources available within the quota to apply the request. |
| 31 | type Quota interface { |
| 32 | // Available judges whether the given request fits within the quota. |
| 33 | Available(req interface{}) bool |
| 34 | // Cost computes the charge against the quota for a given request. |
| 35 | Cost(req interface{}) int |
| 36 | // Remaining is the amount of charge left for the quota. |
| 37 | Remaining() int64 |
| 38 | } |
| 39 | |
| 40 | type passthroughQuota struct{} |
| 41 | |
| 42 | func (*passthroughQuota) Available(interface{}) bool { return true } |
| 43 | func (*passthroughQuota) Cost(interface{}) int { return 0 } |
| 44 | func (*passthroughQuota) Remaining() int64 { return 1 } |
| 45 | |
| 46 | type backendQuota struct { |
| 47 | s *EtcdServer |
| 48 | maxBackendBytes int64 |
| 49 | } |
| 50 | |
| 51 | const ( |
| 52 | // leaseOverhead is an estimate for the cost of storing a lease |
| 53 | leaseOverhead = 64 |
| 54 | // kvOverhead is an estimate for the cost of storing a key's metadata |
| 55 | kvOverhead = 256 |
| 56 | ) |
| 57 | |
| 58 | func NewBackendQuota(s *EtcdServer) Quota { |
| 59 | quotaBackendBytes.Set(float64(s.Cfg.QuotaBackendBytes)) |
| 60 | |
| 61 | if s.Cfg.QuotaBackendBytes < 0 { |
| 62 | // disable quotas if negative |
| 63 | plog.Warningf("disabling backend quota") |
| 64 | return &passthroughQuota{} |
| 65 | } |
| 66 | |
| 67 | if s.Cfg.QuotaBackendBytes == 0 { |
| 68 | // use default size if no quota size given |
| 69 | quotaBackendBytes.Set(float64(DefaultQuotaBytes)) |
| 70 | return &backendQuota{s, DefaultQuotaBytes} |
| 71 | } |
| 72 | |
| 73 | if s.Cfg.QuotaBackendBytes > MaxQuotaBytes { |
| 74 | plog.Warningf("backend quota %v exceeds maximum recommended quota %v", s.Cfg.QuotaBackendBytes, MaxQuotaBytes) |
| 75 | } |
| 76 | return &backendQuota{s, s.Cfg.QuotaBackendBytes} |
| 77 | } |
| 78 | |
| 79 | func (b *backendQuota) Available(v interface{}) bool { |
| 80 | // TODO: maybe optimize backend.Size() |
| 81 | return b.s.Backend().Size()+int64(b.Cost(v)) < b.maxBackendBytes |
| 82 | } |
| 83 | |
| 84 | func (b *backendQuota) Cost(v interface{}) int { |
| 85 | switch r := v.(type) { |
| 86 | case *pb.PutRequest: |
| 87 | return costPut(r) |
| 88 | case *pb.TxnRequest: |
| 89 | return costTxn(r) |
| 90 | case *pb.LeaseGrantRequest: |
| 91 | return leaseOverhead |
| 92 | default: |
| 93 | panic("unexpected cost") |
| 94 | } |
| 95 | } |
| 96 | |
| 97 | func costPut(r *pb.PutRequest) int { return kvOverhead + len(r.Key) + len(r.Value) } |
| 98 | |
| 99 | func costTxnReq(u *pb.RequestOp) int { |
| 100 | r := u.GetRequestPut() |
| 101 | if r == nil { |
| 102 | return 0 |
| 103 | } |
| 104 | return costPut(r) |
| 105 | } |
| 106 | |
| 107 | func costTxn(r *pb.TxnRequest) int { |
| 108 | sizeSuccess := 0 |
| 109 | for _, u := range r.Success { |
| 110 | sizeSuccess += costTxnReq(u) |
| 111 | } |
| 112 | sizeFailure := 0 |
| 113 | for _, u := range r.Failure { |
| 114 | sizeFailure += costTxnReq(u) |
| 115 | } |
| 116 | if sizeFailure > sizeSuccess { |
| 117 | return sizeFailure |
| 118 | } |
| 119 | return sizeSuccess |
| 120 | } |
| 121 | |
| 122 | func (b *backendQuota) Remaining() int64 { |
| 123 | return b.maxBackendBytes - b.s.Backend().Size() |
| 124 | } |