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pkg/tarsum: add dynamic buffer sizing

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This commit makes tarsum buffer allocation dynamic. This change
is required to avoid allocating memory excessively after the archive
buffering changes.

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
This commit is contained in:
unclejack 2014-09-06 15:29:19 +03:00
parent 884c3c7461
commit 76941e89b6
1 changed files with 19 additions and 6 deletions
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25
tarsum/tarsum.go
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@ -16,6 +16,12 @@ import (
"github.com/docker/docker/pkg/log" "github.com/docker/docker/pkg/log"
) )
const (
buf8K = 8 * 1024
buf16K = 16 * 1024
buf32K = 32 * 1024
)
type TarSum struct { type TarSum struct {
io.Reader io.Reader
tarR *tar.Reader tarR *tar.Reader
@ -23,7 +29,7 @@ type TarSum struct {
gz writeCloseFlusher gz writeCloseFlusher
bufTar *bytes.Buffer bufTar *bytes.Buffer
bufGz *bytes.Buffer bufGz *bytes.Buffer
bufData [8192]byte bufData []byte
h hash.Hash h hash.Hash
sums map[string]string sums map[string]string
currentFile string currentFile string
@ -93,12 +99,19 @@ func (ts *TarSum) Read(buf []byte) (int, error) {
if ts.finished { if ts.finished {
return ts.bufGz.Read(buf) return ts.bufGz.Read(buf)
} }
var buf2 []byte if ts.bufData == nil {
if len(buf) > 8192 { switch {
buf2 = make([]byte, len(buf), cap(buf)) case len(buf) <= buf8K:
} else { ts.bufData = make([]byte, buf8K)
buf2 = ts.bufData[:len(buf)-1] case len(buf) <= buf16K:
ts.bufData = make([]byte, buf16K)
case len(buf) <= buf32K:
ts.bufData = make([]byte, buf32K)
default:
ts.bufData = make([]byte, len(buf))
}
} }
buf2 := ts.bufData[:len(buf)-1]
n, err := ts.tarR.Read(buf2) n, err := ts.tarR.Read(buf2)
if err != nil { if err != nil {