diff options
author | Xinfeng Liu <xinfeng.liu@gmail.com> | 2019-04-23 02:33:20 +0000 |
---|---|---|
committer | Kir Kolyshkin <kolyshkin@gmail.com> | 2019-05-09 11:05:16 -0700 |
commit | 05250a4f0094e6802dd7d338d632ea632d0c7e34 (patch) | |
tree | c291628e2b3380ed4f1aa0e8a3808c4957e7c9da /layer | |
parent | f73b5cb4e8b9a23ad6700577840582d66017a733 (diff) |
layer: optimize layerStore mountL
Goroutine stack analisys shown some lock contention
while doing massively (100 instances of `docker rm`)
parallel image removal, with many goroutines waiting
for the mountL mutex. Optimize it.
With this commit, the above operation is about 3x
faster, with no noticeable change to container
creation times (tested on aufs and overlay2).
kolyshkin@:
- squashed commits
- added description
- protected CreateRWLayer against name collisions by
temporary assiging nil to ls.mounts[name], and treating
nil as "non-existent" in all the other functions.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Diffstat (limited to 'layer')
-rw-r--r-- | layer/layer_store.go | 50 | ||||
-rw-r--r-- | layer/migration.go | 6 |
2 files changed, 35 insertions, 21 deletions
diff --git a/layer/layer_store.go b/layer/layer_store.go index 1601465c04..737283cc2d 100644 --- a/layer/layer_store.go +++ b/layer/layer_store.go @@ -189,7 +189,9 @@ func (ls *layerStore) loadLayer(layer ChainID) (*roLayer, error) { } func (ls *layerStore) loadMount(mount string) error { - if _, ok := ls.mounts[mount]; ok { + ls.mountL.Lock() + defer ls.mountL.Unlock() + if m := ls.mounts[mount]; m != nil { return nil } @@ -477,7 +479,7 @@ func (ls *layerStore) Release(l Layer) ([]Metadata, error) { return ls.releaseLayer(layer) } -func (ls *layerStore) CreateRWLayer(name string, parent ChainID, opts *CreateRWLayerOpts) (RWLayer, error) { +func (ls *layerStore) CreateRWLayer(name string, parent ChainID, opts *CreateRWLayerOpts) (_ RWLayer, err error) { var ( storageOpt map[string]string initFunc MountInit @@ -491,13 +493,21 @@ func (ls *layerStore) CreateRWLayer(name string, parent ChainID, opts *CreateRWL } ls.mountL.Lock() - defer ls.mountL.Unlock() - m, ok := ls.mounts[name] - if ok { + if _, ok := ls.mounts[name]; ok { + ls.mountL.Unlock() return nil, ErrMountNameConflict } + // Avoid name collision by temporary assigning nil + ls.mounts[name] = nil + ls.mountL.Unlock() + defer func() { + if err != nil { + ls.mountL.Lock() + delete(ls.mounts, name) + ls.mountL.Unlock() + } + }() - var err error var pid string var p *roLayer if string(parent) != "" { @@ -517,7 +527,7 @@ func (ls *layerStore) CreateRWLayer(name string, parent ChainID, opts *CreateRWL }() } - m = &mountedLayer{ + m := &mountedLayer{ name: name, parent: p, mountID: ls.mountID(name), @@ -528,7 +538,7 @@ func (ls *layerStore) CreateRWLayer(name string, parent ChainID, opts *CreateRWL if initFunc != nil { pid, err = ls.initMount(m.mountID, pid, mountLabel, initFunc, storageOpt) if err != nil { - return nil, err + return } m.initID = pid } @@ -538,10 +548,10 @@ func (ls *layerStore) CreateRWLayer(name string, parent ChainID, opts *CreateRWL } if err = ls.driver.CreateReadWrite(m.mountID, pid, createOpts); err != nil { - return nil, err + return } if err = ls.saveMount(m); err != nil { - return nil, err + return } return m.getReference(), nil @@ -549,9 +559,9 @@ func (ls *layerStore) CreateRWLayer(name string, parent ChainID, opts *CreateRWL func (ls *layerStore) GetRWLayer(id string) (RWLayer, error) { ls.mountL.Lock() - defer ls.mountL.Unlock() - mount, ok := ls.mounts[id] - if !ok { + mount := ls.mounts[id] + ls.mountL.Unlock() + if mount == nil { return nil, ErrMountDoesNotExist } @@ -561,8 +571,8 @@ func (ls *layerStore) GetRWLayer(id string) (RWLayer, error) { func (ls *layerStore) GetMountID(id string) (string, error) { ls.mountL.Lock() defer ls.mountL.Unlock() - mount, ok := ls.mounts[id] - if !ok { + mount := ls.mounts[id] + if mount == nil { return "", ErrMountDoesNotExist } logrus.Debugf("GetMountID id: %s -> mountID: %s", id, mount.mountID) @@ -572,9 +582,9 @@ func (ls *layerStore) GetMountID(id string) (string, error) { func (ls *layerStore) ReleaseRWLayer(l RWLayer) ([]Metadata, error) { ls.mountL.Lock() - defer ls.mountL.Unlock() - m, ok := ls.mounts[l.Name()] - if !ok { + m := ls.mounts[l.Name()] + ls.mountL.Unlock() + if m == nil { return []Metadata{}, nil } @@ -606,7 +616,9 @@ func (ls *layerStore) ReleaseRWLayer(l RWLayer) ([]Metadata, error) { return nil, err } + ls.mountL.Lock() delete(ls.mounts, m.Name()) + ls.mountL.Unlock() ls.layerL.Lock() defer ls.layerL.Unlock() @@ -634,7 +646,9 @@ func (ls *layerStore) saveMount(mount *mountedLayer) error { } } + ls.mountL.Lock() ls.mounts[mount.name] = mount + ls.mountL.Unlock() return nil } diff --git a/layer/migration.go b/layer/migration.go index 2668ea96bb..775e552fee 100644 --- a/layer/migration.go +++ b/layer/migration.go @@ -18,9 +18,9 @@ import ( // after migration the layer may be retrieved by the given name. func (ls *layerStore) CreateRWLayerByGraphID(name, graphID string, parent ChainID) (err error) { ls.mountL.Lock() - defer ls.mountL.Unlock() - m, ok := ls.mounts[name] - if ok { + m := ls.mounts[name] + ls.mountL.Unlock() + if m != nil { if m.parent.chainID != parent { return errors.New("name conflict, mismatched parent") } |