optimize memory allocs during reconstruct (#4964)

The reedsolomon library now avoids allocations during reconstruction.
This change exploits that to reduce memory allocs and GC preasure during
healing and reading.

pkg/bpool/bpool.go

@@ -1,69 +0,0 @@
-/*
- * Minio Cloud Storage, (C) 2016 Minio, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-// Package bpool implements a fixed size pool of byte slices.
-package bpool
-
-import (
-	"errors"
-	"sync"
-)
-
-// ErrBpoolNoFree - Normally this error should never be returned, this error
-// indicates a bug in the package consumer.
-var ErrBpoolNoFree = errors.New("no free byte slice in pool")
-
-// BytePool - temporary pool of byte slices.
-type BytePool struct {
-	buf  [][]byte // array of byte slices
-	used []bool   // indicates if a buf[i] is in use
-	size int64    // size of buf[i]
-	mu   sync.Mutex
-}
-
-// Get - Returns an unused byte slice.
-func (b *BytePool) Get() (buf []byte, err error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	for i := 0; i < len(b.used); i++ {
-		if !b.used[i] {
-			b.used[i] = true
-			if b.buf[i] == nil {
-				b.buf[i] = make([]byte, b.size)
-			}
-			return b.buf[i], nil
-		}
-	}
-	return nil, ErrBpoolNoFree
-}
-
-// Reset - Marks all slices as unused.
-func (b *BytePool) Reset() {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	for i := 0; i < len(b.used); i++ {
-		b.used[i] = false
-	}
-}
-
-// NewBytePool - Returns new pool.
-// size - length of each slice.
-// n - number of slices in the pool.
-func NewBytePool(size int64, n int) *BytePool {
-	used := make([]bool, n)
-	buf := make([][]byte, n)
-	return &BytePool{buf, used, size, sync.Mutex{}}
-}

pkg/bpool/bpool_test.go

@@ -1,53 +0,0 @@
-/*
- * Minio Cloud Storage, (C) 2016 Minio, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package bpool
-
-import "testing"
-
-func TestBytePool(t *testing.T) {
-	size := int64(10)
-	n := 16
-	pool := NewBytePool(size, n)
-	enBlocks := make([][]byte, n)
-
-	// Allocates all the 16 byte slices in the pool.
-	alloc := func() {
-		for i := range enBlocks {
-			var err error
-			enBlocks[i], err = pool.Get()
-			if err != nil {
-				t.Fatal("expected nil, got", err)
-			}
-			// Make sure the slice length is as expected.
-			if len(enBlocks[i]) != int(size) {
-				t.Fatalf("expected size %d, got %d", len(enBlocks[i]), size)
-			}
-		}
-	}
-
-	// Allocate everything in the pool.
-	alloc()
-	// Any Get() will fail when the pool does not have any free buffer.
-	_, err := pool.Get()
-	if err == nil {
-		t.Fatalf("expected %s, got nil", err)
-	}
-	// Reset - so that all the buffers are marked as unused.
-	pool.Reset()
-	// Allocation of all the buffers in the pool should succeed now.
-	alloc()
-}