github.com/zuoyebang/bitalosdb@v1.1.1-0.20240516111551-79a8c4d8ce20/internal/vfs/prefetch_linux.go (about)

     1  // Copyright 2021 The Bitalosdb author(hustxrb@163.com) and other contributors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  //go:build linux
    16  
    17  package vfs
    18  
    19  import "syscall"
    20  
    21  // Prefetch signals the OS (on supported platforms) to fetch the next size
    22  // bytes in file (as returned by os.File.Fd()) after offset into cache. Any
    23  // subsequent reads in that range will not issue disk IO.
    24  func Prefetch(file uintptr, offset uint64, size uint64) error {
    25  	_, _, err := syscall.Syscall(syscall.SYS_READAHEAD, uintptr(file), uintptr(offset), uintptr(size))
    26  	return err
    27  }