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22801e071f
This moves the initialization of the pre-defined networks to where it's
used instead of in package init.
This reason for this change is having this be populated in `init()`
causes it to always consume cpu, and memory (4.3MB of memory), to
populate even if the package is unused (like for instnace, in a re-exec).
Here is a memory profile of docker/docker just after starting the daemon of the
top 10 largest memory consumers:
Before:
```
flat flat% sum% cum cum%
0 0% 0% 11.89MB 95.96% runtime.goexit
0 0% 0% 6.79MB 54.82% runtime.main
0 0% 0% 5.79MB 46.74% main.init
0 0% 0% 4.79MB 38.67% github.com/docker/docker/api/server/router/network.init
0 0% 0% 4.79MB 38.67% github.com/docker/libnetwork.init
0 0% 0% 4.29MB 34.63% github.com/docker/libnetwork/ipam.init
0 0% 0% 4.29MB 34.63% github.com/docker/libnetwork/ipams/builtin.init
0 0% 0% 4.29MB 34.63% github.com/docker/libnetwork/ipamutils.init
0 0% 0% 4.29MB 34.63% github.com/docker/libnetwork/ipamutils.init.1
4.29MB 34.63% 34.63% 4.29MB 34.63% github.com/docker/libnetwork/ipamutils.initGranularPredefinedNetworks
```
After:
```
flat flat% sum% cum cum%
0 0% 0% 4439.37kB 89.66% runtime.goexit
0 0% 0% 4439.37kB 89.66% runtime.main
0 0% 0% 3882.11kB 78.40% github.com/docker/docker/cli.(*Cli).Run
0 0% 0% 3882.11kB 78.40% main.main
3882.11kB 78.40% 78.40% 3882.11kB 78.40% reflect.callMethod
0 0% 78.40% 3882.11kB 78.40% reflect.methodValueCall
0 0% 78.40% 557.26kB 11.25% github.com/docker/docker/api/server.init
557.26kB 11.25% 89.66% 557.26kB 11.25% html.init
0 0% 89.66% 557.26kB 11.25% html/template.init
0 0% 89.66% 557.26kB 11.25% main.init
```
Now, of course the docker daemon will still need to consume this memory, but
at least now re-execs and such won't have to re-init these variables.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
50 lines
1.5 KiB
Go
50 lines
1.5 KiB
Go
// Package ipamutils provides utililty functions for ipam management
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package ipamutils
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import (
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"net"
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"sync"
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)
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var (
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// PredefinedBroadNetworks contains a list of 31 IPv4 private networks with host size 16 and 12
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// (172.17-31.x.x/16, 192.168.x.x/20) which do not overlap with the networks in `PredefinedGranularNetworks`
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PredefinedBroadNetworks []*net.IPNet
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// PredefinedGranularNetworks contains a list of 64K IPv4 private networks with host size 8
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// (10.x.x.x/24) which do not overlap with the networks in `PredefinedBroadNetworks`
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PredefinedGranularNetworks []*net.IPNet
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initNetworksOnce sync.Once
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)
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// InitNetworks initializes the pre-defined networks used by the built-in IP allocator
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func InitNetworks() {
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initNetworksOnce.Do(func() {
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PredefinedBroadNetworks = initBroadPredefinedNetworks()
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PredefinedGranularNetworks = initGranularPredefinedNetworks()
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})
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}
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func initBroadPredefinedNetworks() []*net.IPNet {
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pl := make([]*net.IPNet, 0, 31)
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mask := []byte{255, 255, 0, 0}
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for i := 17; i < 32; i++ {
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pl = append(pl, &net.IPNet{IP: []byte{172, byte(i), 0, 0}, Mask: mask})
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}
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mask20 := []byte{255, 255, 240, 0}
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for i := 0; i < 16; i++ {
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pl = append(pl, &net.IPNet{IP: []byte{192, 168, byte(i << 4), 0}, Mask: mask20})
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}
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return pl
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}
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func initGranularPredefinedNetworks() []*net.IPNet {
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pl := make([]*net.IPNet, 0, 256*256)
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mask := []byte{255, 255, 255, 0}
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for i := 0; i < 256; i++ {
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for j := 0; j < 256; j++ {
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pl = append(pl, &net.IPNet{IP: []byte{10, byte(i), byte(j), 0}, Mask: mask})
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}
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}
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return pl
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}
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