containerd/linux/proc/io.go
Stephen J Day cd72819b53
archive, cio, cmd, linux: use buffer pools
To avoid buffer bloat in long running processes, we try to use buffer
pools where possible. This is meant to address shim memory usage issues,
but may not be the root cause.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2018-01-22 13:52:06 -08:00

83 lines
1.7 KiB
Go

// +build !windows
package proc
import (
"context"
"fmt"
"io"
"sync"
"syscall"
"github.com/containerd/fifo"
runc "github.com/containerd/go-runc"
)
var bufPool = sync.Pool{
New: func() interface{} {
buffer := make([]byte, 32<<10)
return &buffer
},
}
func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, wg, cwg *sync.WaitGroup) error {
for name, dest := range map[string]func(wc io.WriteCloser, rc io.Closer){
stdout: func(wc io.WriteCloser, rc io.Closer) {
wg.Add(1)
cwg.Add(1)
go func() {
cwg.Done()
p := bufPool.Get().(*[]byte)
defer bufPool.Put(p)
io.CopyBuffer(wc, rio.Stdout(), *p)
wg.Done()
wc.Close()
rc.Close()
}()
},
stderr: func(wc io.WriteCloser, rc io.Closer) {
wg.Add(1)
cwg.Add(1)
go func() {
cwg.Done()
p := bufPool.Get().(*[]byte)
defer bufPool.Put(p)
io.CopyBuffer(wc, rio.Stderr(), *p)
wg.Done()
wc.Close()
rc.Close()
}()
},
} {
fw, err := fifo.OpenFifo(ctx, name, syscall.O_WRONLY, 0)
if err != nil {
return fmt.Errorf("containerd-shim: opening %s failed: %s", name, err)
}
fr, err := fifo.OpenFifo(ctx, name, syscall.O_RDONLY, 0)
if err != nil {
return fmt.Errorf("containerd-shim: opening %s failed: %s", name, err)
}
dest(fw, fr)
}
if stdin == "" {
rio.Stdin().Close()
return nil
}
f, err := fifo.OpenFifo(ctx, stdin, syscall.O_RDONLY, 0)
if err != nil {
return fmt.Errorf("containerd-shim: opening %s failed: %s", stdin, err)
}
cwg.Add(1)
go func() {
cwg.Done()
p := bufPool.Get().(*[]byte)
defer bufPool.Put(p)
io.CopyBuffer(rio.Stdin(), f, *p)
rio.Stdin().Close()
f.Close()
}()
return nil
}