fuse: remove custom BufferPool as tunable option

fuse/api.go

@@ -130,9 +130,6 @@ type MountOptions struct {
 	// interested in security labels.
 	IgnoreSecurityLabels bool // ignoring labels should be provided as a fusermount mount option.
 
-	// If given, use this buffer pool instead of the global one.
-	Buffers BufferPool
-
 	// If RememberInodes is set, we will never forget inodes.
 	// This may be useful for NFS.
 	RememberInodes bool

fuse/bufferpool.go

@@ -9,39 +9,18 @@ import (
 	"sync"
 )
 
-// BufferPool implements explicit memory management. It is used for
+// bufferPool implements explicit memory management. It is used for
 // minimizing the GC overhead of communicating with the kernel.
-type BufferPool interface {
-	// AllocBuffer creates a buffer of at least the given size. After use,
-	// it should be deallocated with FreeBuffer().
-	AllocBuffer(size uint32) []byte
-
-	// FreeBuffer takes back a buffer if it was allocated through
-	// AllocBuffer.  It is not an error to call FreeBuffer() on a slice
-	// obtained elsewhere.
-	FreeBuffer(slice []byte)
-}
-
-type bufferPoolImpl struct {
+type bufferPool struct {
 	lock sync.Mutex
 
 	// For each page size multiple a list of slice pointers.
 	buffersBySize []*sync.Pool
 }
 
-// NewBufferPool returns a BufferPool implementation that that returns
-// slices with capacity of a multiple of page size, which have possibly
-// been used, and may contain random contents. When using
-// NewBufferPool, file system handlers may not hang on to passed-in
-// buffers beyond the handler's return.
-func NewBufferPool() BufferPool {
-	bp := new(bufferPoolImpl)
-	return bp
-}
-
 var pageSize = os.Getpagesize()
 
-func (p *bufferPoolImpl) getPool(pageCount int) *sync.Pool {
+func (p *bufferPool) getPool(pageCount int) *sync.Pool {
 	p.lock.Lock()
 	for len(p.buffersBySize) < pageCount+1 {
 		p.buffersBySize = append(p.buffersBySize, nil)
@@ -56,7 +35,9 @@ func (p *bufferPoolImpl) getPool(pageCount int) *sync.Pool {
 	return pool
 }
 
-func (p *bufferPoolImpl) AllocBuffer(size uint32) []byte {
+// AllocBuffer creates a buffer of at least the given size. After use,
+// it should be deallocated with FreeBuffer().
+func (p *bufferPool) AllocBuffer(size uint32) []byte {
 	sz := int(size)
 	if sz < pageSize {
 		sz = pageSize
@@ -71,7 +52,10 @@ func (p *bufferPoolImpl) AllocBuffer(size uint32) []byte {
 	return b[:size]
 }
 
-func (p *bufferPoolImpl) FreeBuffer(slice []byte) {
+// FreeBuffer takes back a buffer if it was allocated through
+// AllocBuffer.  It is not an error to call FreeBuffer() on a slice
+// obtained elsewhere.
+func (p *bufferPool) FreeBuffer(slice []byte) {
 	if slice == nil {
 		return
 	}

fuse/bufferpool_test.go

@@ -9,11 +9,14 @@ import (
 )
 
 func TestBufferPool(t *testing.T) {
-	bp := NewBufferPool()
+	bp := bufferPool{}
 	size := 1500
-	buf := bp.AllocBuffer(uint32(size))
-	if len(buf) != size {
-		t.Errorf("Expected buffer of %d bytes, got %d bytes", size, len(buf))
+	buf1 := bp.AllocBuffer(uint32(size))
+	if len(buf1) != size {
+		t.Errorf("Expected buffer of %d bytes, got %d bytes", size, len(buf1))
 	}
-	bp.FreeBuffer(buf)
+	bp.FreeBuffer(buf1)
+
+	// tried testing to see if we get buf1 back if we ask again,
+	// but it's not guaranteed and sometimes fails
 }

fuse/server.go

@@ -39,6 +39,9 @@ type Server struct {
 
 	opts *MountOptions
 
+	// Pools for []byte
+	buffers bufferPool
+
 	// Pool for request structs.
 	reqPool sync.Pool
 
@@ -132,9 +135,6 @@ func NewServer(fs RawFileSystem, mountPoint string, opts *MountOptions) (*Server
 		fs = NewLockingRawFileSystem(fs)
 	}
 
-	if o.Buffers == nil {
-		o.Buffers = defaultBufferPool
-	}
 	if o.MaxWrite < 0 {
 		o.MaxWrite = 0
 	}
@@ -300,7 +300,7 @@ func (ms *Server) returnRequest(req *request) {
 	ms.recordStats(req)
 
 	if req.bufferPoolOutputBuf != nil {
-		ms.opts.Buffers.FreeBuffer(req.bufferPoolOutputBuf)
+		ms.buffers.FreeBuffer(req.bufferPoolOutputBuf)
 		req.bufferPoolOutputBuf = nil
 	}
 
@@ -446,9 +446,9 @@ func (ms *Server) allocOut(req *request, size uint32) []byte {
 		return req.bufferPoolOutputBuf
 	}
 	if req.bufferPoolOutputBuf != nil {
-		ms.opts.Buffers.FreeBuffer(req.bufferPoolOutputBuf)
+		ms.buffers.FreeBuffer(req.bufferPoolOutputBuf)
 	}
-	req.bufferPoolOutputBuf = ms.opts.Buffers.AllocBuffer(size)
+	req.bufferPoolOutputBuf = ms.buffers.AllocBuffer(size)
 	return req.bufferPoolOutputBuf
 }
 
@@ -787,12 +787,6 @@ func (in *InitIn) SupportsNotify(notifyType int) bool {
 	return false
 }
 
-var defaultBufferPool BufferPool
-
-func init() {
-	defaultBufferPool = NewBufferPool()
-}
-
 // WaitMount waits for the first request to be served. Use this to
 // avoid racing between accessing the (empty or not yet mounted)
 // mountpoint, and the OS trying to setup the user-space mount.