mirror of
https://github.com/hanzoai/visor.git
synced 2026-09-24 17:04:14 +00:00
Jamie LiuandgVisor bot
406172e308
Aside from improving checkpointing performance by using AIO to better utilize disk bandwidth, this makes it possible to parallelize writing pages with scanning for zero pages (in a following CL). As part of this, update and document ownership semantics for the state file, pages metadata file, and pages file, with the following goals: - Since io.WriteCloser.Close() may flush buffers, it must return a nil error before write success is reported - The pages metadata file is closed while async page saving is in progress (to hide the latency of the former) PiperOrigin-RevId: 814315485
63 lines
2.5 KiB
Go
63 lines
2.5 KiB
Go
// Copyright 2025 The gVisor Authors.
|
|
//
|
|
// 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 stateio
|
|
|
|
import (
|
|
"gvisor.dev/gvisor/pkg/hostarch"
|
|
)
|
|
|
|
const (
|
|
pagesFileFDDefaultMaxIOBytes = 256 << 10
|
|
pagesFileFDDefaultMaxParallel = 128
|
|
)
|
|
|
|
// NewPagesFileFDReader returns a FDReader that reads a pages file from the
|
|
// given host file descriptor. It takes ownership of the file descriptor.
|
|
//
|
|
// Preconditions:
|
|
// - hostarch.PageSize <= maxReadBytes <= linux.MAX_RW_COUNT.
|
|
// - maxParallel > 0.
|
|
func NewPagesFileFDReader(fd int32, maxReadBytes uint64, maxParallel int) *FDReader {
|
|
// Provision one range per page of maxReadBytes, since this is the maximum
|
|
// number of ranges that async page loading will use.
|
|
return NewFDReader(fd, maxReadBytes, int(maxReadBytes/hostarch.PageSize), maxParallel)
|
|
}
|
|
|
|
// NewPagesFileFDReaderDefault returns a FDReader that reads a pages file from
|
|
// the given host file descriptor, using defaults for MaxReadBytes and
|
|
// MaxParallel. It takes ownership of the file descriptor.
|
|
func NewPagesFileFDReaderDefault(fd int32) *FDReader {
|
|
return NewPagesFileFDReader(fd, pagesFileFDDefaultMaxIOBytes, pagesFileFDDefaultMaxParallel)
|
|
}
|
|
|
|
// NewPagesFileFDWriter returns a FDWriter that writes a pages file to the
|
|
// given host file descriptor. It takes ownership of the file descriptor.
|
|
//
|
|
// Preconditions:
|
|
// - hostarch.PageSize <= maxWriteBytes <= linux.MAX_RW_COUNT.
|
|
// - maxParallel > 0.
|
|
func NewPagesFileFDWriter(fd int32, maxWriteBytes uint64, maxParallel int) *FDWriter {
|
|
// Provision one range per page of maxWriteBytes, since this is the maximum
|
|
// number of ranges that async page saving will use.
|
|
return NewFDWriter(fd, maxWriteBytes, int(maxWriteBytes/hostarch.PageSize), maxParallel)
|
|
}
|
|
|
|
// NewPagesFileFDWriterDefault returns a FDWriter that writes to the given host
|
|
// file descriptor, using defaults for MaxWriteBytes and MaxParallel. It takes
|
|
// ownership of the file descriptor.
|
|
func NewPagesFileFDWriterDefault(fd int32) *FDWriter {
|
|
return NewPagesFileFDWriter(fd, pagesFileFDDefaultMaxIOBytes, pagesFileFDDefaultMaxParallel)
|
|
}
|