github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sentry/fs/proc/meminfo.go (about)

     1  // Copyright 2018 The gVisor Authors.
     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  package proc
    16  
    17  import (
    18  	"bytes"
    19  	"fmt"
    20  
    21  	"github.com/SagerNet/gvisor/pkg/context"
    22  	"github.com/SagerNet/gvisor/pkg/hostarch"
    23  	"github.com/SagerNet/gvisor/pkg/sentry/fs/proc/seqfile"
    24  	"github.com/SagerNet/gvisor/pkg/sentry/kernel"
    25  	"github.com/SagerNet/gvisor/pkg/sentry/usage"
    26  )
    27  
    28  // LINT.IfChange
    29  
    30  // meminfoData backs /proc/meminfo.
    31  //
    32  // +stateify savable
    33  type meminfoData struct {
    34  	// k is the owning Kernel.
    35  	k *kernel.Kernel
    36  }
    37  
    38  // NeedsUpdate implements seqfile.SeqSource.NeedsUpdate.
    39  func (*meminfoData) NeedsUpdate(generation int64) bool {
    40  	return true
    41  }
    42  
    43  // ReadSeqFileData implements seqfile.SeqSource.ReadSeqFileData.
    44  func (d *meminfoData) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
    45  	if h != nil {
    46  		return nil, 0
    47  	}
    48  
    49  	mf := d.k.MemoryFile()
    50  	mf.UpdateUsage()
    51  	snapshot, totalUsage := usage.MemoryAccounting.Copy()
    52  	totalSize := usage.TotalMemory(mf.TotalSize(), totalUsage)
    53  	anon := snapshot.Anonymous + snapshot.Tmpfs
    54  	file := snapshot.PageCache + snapshot.Mapped
    55  	// We don't actually have active/inactive LRUs, so just make up numbers.
    56  	activeFile := (file / 2) &^ (hostarch.PageSize - 1)
    57  	inactiveFile := file - activeFile
    58  
    59  	var buf bytes.Buffer
    60  	fmt.Fprintf(&buf, "MemTotal:       %8d kB\n", totalSize/1024)
    61  	memFree := totalSize - totalUsage
    62  	if memFree > totalSize {
    63  		// Underflow.
    64  		memFree = 0
    65  	}
    66  	// We use MemFree as MemAvailable because we don't swap.
    67  	// TODO(rahat): When reclaim is implemented the value of MemAvailable
    68  	// should change.
    69  	fmt.Fprintf(&buf, "MemFree:        %8d kB\n", memFree/1024)
    70  	fmt.Fprintf(&buf, "MemAvailable:   %8d kB\n", memFree/1024)
    71  	fmt.Fprintf(&buf, "Buffers:               0 kB\n") // memory usage by block devices
    72  	fmt.Fprintf(&buf, "Cached:         %8d kB\n", (file+snapshot.Tmpfs)/1024)
    73  	// Emulate a system with no swap, which disables inactivation of anon pages.
    74  	fmt.Fprintf(&buf, "SwapCache:             0 kB\n")
    75  	fmt.Fprintf(&buf, "Active:         %8d kB\n", (anon+activeFile)/1024)
    76  	fmt.Fprintf(&buf, "Inactive:       %8d kB\n", inactiveFile/1024)
    77  	fmt.Fprintf(&buf, "Active(anon):   %8d kB\n", anon/1024)
    78  	fmt.Fprintf(&buf, "Inactive(anon):        0 kB\n")
    79  	fmt.Fprintf(&buf, "Active(file):   %8d kB\n", activeFile/1024)
    80  	fmt.Fprintf(&buf, "Inactive(file): %8d kB\n", inactiveFile/1024)
    81  	fmt.Fprintf(&buf, "Unevictable:           0 kB\n") // TODO(b/31823263)
    82  	fmt.Fprintf(&buf, "Mlocked:               0 kB\n") // TODO(b/31823263)
    83  	fmt.Fprintf(&buf, "SwapTotal:             0 kB\n")
    84  	fmt.Fprintf(&buf, "SwapFree:              0 kB\n")
    85  	fmt.Fprintf(&buf, "Dirty:                 0 kB\n")
    86  	fmt.Fprintf(&buf, "Writeback:             0 kB\n")
    87  	fmt.Fprintf(&buf, "AnonPages:      %8d kB\n", anon/1024)
    88  	fmt.Fprintf(&buf, "Mapped:         %8d kB\n", file/1024) // doesn't count mapped tmpfs, which we don't know
    89  	fmt.Fprintf(&buf, "Shmem:          %8d kB\n", snapshot.Tmpfs/1024)
    90  	return []seqfile.SeqData{{Buf: buf.Bytes(), Handle: (*meminfoData)(nil)}}, 0
    91  }
    92  
    93  // LINT.ThenChange(../../fsimpl/proc/tasks_files.go)