[chore]: Bump github.com/KimMachineGun/automemlimit from 0.4.0 to 0.5.0 (#2560)

go.mod

@@ -21,7 +21,7 @@ require (
 	codeberg.org/gruf/go-structr v0.1.1
 	codeberg.org/superseriousbusiness/exif-terminator v0.7.0
 	github.com/DmitriyVTitov/size v1.5.0
-	github.com/KimMachineGun/automemlimit v0.4.0
+	github.com/KimMachineGun/automemlimit v0.5.0
 	github.com/abema/go-mp4 v1.1.1
 	github.com/buckket/go-blurhash v1.1.0
 	github.com/coreos/go-oidc/v3 v3.9.0
@@ -143,6 +143,7 @@ require (
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/opencontainers/runtime-spec v1.0.2 // indirect
+	github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58 // indirect
 	github.com/pelletier/go-toml/v2 v2.1.1 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect

go.sum

@@ -79,8 +79,8 @@ github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/DmitriyVTitov/size v1.5.0 h1:/PzqxYrOyOUX1BXj6J9OuVRVGe+66VL4D9FlUaW515g=
 github.com/DmitriyVTitov/size v1.5.0/go.mod h1:le6rNI4CoLQV1b9gzp1+3d7hMAD/uu2QcJ+aYbNgiU0=
-github.com/KimMachineGun/automemlimit v0.4.0 h1:qOjSDbAUENEL6fiKmRKuAVhPaLijpoEHFDTE+I+prp0=
-github.com/KimMachineGun/automemlimit v0.4.0/go.mod h1:pJhTW/nWJMj6SnWSU2TEKSlCaM+1N5Mej+IfS/5/Ol0=
+github.com/KimMachineGun/automemlimit v0.5.0 h1:BeOe+BbJc8L5chL3OwzVYjVzyvPALdd5wxVVOWuUZmQ=
+github.com/KimMachineGun/automemlimit v0.5.0/go.mod h1:di3GCKiu9Y+1fs92erCbUvKzPkNyViN3mA0vti/ykEQ=
 github.com/abema/go-mp4 v1.1.1 h1:OfzkdMO6SWTBR1ltNSVwlTHatrAK9I3iYLQfkdEMMuc=
 github.com/abema/go-mp4 v1.1.1/go.mod h1:vPl9t5ZK7K0x68jh12/+ECWBCXoWuIDtNgPtU2f04ws=
 github.com/ajg/form v1.5.1 h1:t9c7v8JUKu/XxOGBU0yjNpaMloxGEJhUkqFRq0ibGeU=
@@ -416,6 +416,8 @@ github.com/opencontainers/runtime-spec v1.0.2 h1:UfAcuLBJB9Coz72x1hgl8O5RVzTdNia
 github.com/opencontainers/runtime-spec v1.0.2/go.mod h1:jwyrGlmzljRJv/Fgzds9SsS/C5hL+LL3ko9hs6T5lQ0=
 github.com/orcaman/writerseeker v0.0.0-20200621085525-1d3f536ff85e h1:s2RNOM/IGdY0Y6qfTeUKhDawdHDpK9RGBdx80qN4Ttw=
 github.com/orcaman/writerseeker v0.0.0-20200621085525-1d3f536ff85e/go.mod h1:nBdnFKj15wFbf94Rwfq4m30eAcyY9V/IyKAGQFtqkW0=
+github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58 h1:onHthvaw9LFnH4t2DcNVpwGmV9E1BkGknEliJkfwQj0=
+github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58/go.mod h1:DXv8WO4yhMYhSNPKjeNKa5WY9YCIEBRbNzFFPJbWO6Y=
 github.com/pelletier/go-toml/v2 v2.0.1/go.mod h1:r9LEWfGN8R5k0VXJ+0BkIe7MYkRdwZOjgMj2KwnJFUo=
 github.com/pelletier/go-toml/v2 v2.1.1 h1:LWAJwfNvjQZCFIDKWYQaM62NcYeYViCmWIwmOStowAI=
 github.com/pelletier/go-toml/v2 v2.1.1/go.mod h1:tJU2Z3ZkXwnxa4DPO899bsyIoywizdUvyaeZurnPPDc=

vendor/github.com/KimMachineGun/automemlimit/README.md

@@ -8,6 +8,14 @@ Automatically set `GOMEMLIMIT` to match Linux [cgroups(7)](https://man7.org/linu
 
 See more details about `GOMEMLIMIT` [here](https://tip.golang.org/doc/gc-guide#Memory_limit).
 
+## Notice
+
+Version `v0.5.0` introduces a fallback to system memory limits as an experimental feature when cgroup limits are unavailable. Activate this by setting `AUTOMEMLIMIT_EXPERIMENT=system`.
+You can also use system memory limits via `memlimit.FromSystem` provider directly.
+
+This feature is under evaluation and might become a default or be removed based on user feedback.
+If you have any feedback about this feature, please open an issue.
+
 ## Installation
 
 ```shell
@@ -34,9 +42,17 @@ import "github.com/KimMachineGun/automemlimit/memlimit"
 func init() {
 	memlimit.SetGoMemLimitWithOpts(
 		memlimit.WithRatio(0.9),
-		memlimit.WithEnv(),
 		memlimit.WithProvider(memlimit.FromCgroup),
 	)
+	memlimit.SetGoMemLimitWithOpts(
+		memlimit.WithRatio(0.9),
+		memlimit.WithProvider(
+			memlimit.ApplyFallback(
+				memlimit.FromCgroup,
+				memlimit.FromSystem,
+			),
+		),
+	)
 	memlimit.SetGoMemLimitWithEnv()
 	memlimit.SetGoMemLimit(0.9)
 	memlimit.SetGoMemLimitWithProvider(memlimit.Limit(1024*1024), 0.9)

vendor/github.com/KimMachineGun/automemlimit/memlimit/cgroups.go

@@ -1,91 +1,12 @@
-//go:build linux
-// +build linux
-
 package memlimit
 
 import (
-	"path/filepath"
-
-	"github.com/containerd/cgroups/v3"
-	"github.com/containerd/cgroups/v3/cgroup1"
-	"github.com/containerd/cgroups/v3/cgroup2"
+	"errors"
 )
 
-const (
-	cgroupMountPoint = "/sys/fs/cgroup"
+var (
+	// ErrNoCgroup is returned when the process is not in cgroup.
+	ErrNoCgroup = errors.New("process is not in cgroup")
+	// ErrCgroupsNotSupported is returned when the system does not support cgroups.
+	ErrCgroupsNotSupported = errors.New("cgroups is not supported on this system")
 )
-
-// FromCgroup returns the memory limit based on the cgroups version on this system.
-func FromCgroup() (uint64, error) {
-	switch cgroups.Mode() {
-	case cgroups.Legacy:
-		return FromCgroupV1()
-	case cgroups.Hybrid:
-		return FromCgroupHybrid()
-	case cgroups.Unified:
-		return FromCgroupV2()
-	}
-	return 0, ErrNoCgroup
-}
-
-// FromCgroupV1 returns the memory limit from the cgroup v1.
-func FromCgroupV1() (uint64, error) {
-	cg, err := cgroup1.Load(cgroup1.RootPath, cgroup1.WithHiearchy(
-		cgroup1.SingleSubsystem(cgroup1.Default, cgroup1.Memory),
-	))
-	if err != nil {
-		return 0, err
-	}
-
-	metrics, err := cg.Stat(cgroup1.IgnoreNotExist)
-	if err != nil {
-		return 0, err
-	}
-
-	if limit := metrics.GetMemory().GetHierarchicalMemoryLimit(); limit != 0 {
-		return limit, nil
-	}
-
-	return 0, ErrNoLimit
-}
-
-// FromCgroupHybrid returns the memory limit from the cgroup v1 or v2.
-// It checks the cgroup v2 first, and if it fails, it falls back to cgroup v1.
-func FromCgroupHybrid() (uint64, error) {
-	limit, err := fromCgroupV2(filepath.Join(cgroupMountPoint, "unified"))
-	if err == nil {
-		return limit, nil
-	} else if err != ErrNoLimit {
-		return 0, err
-	}
-
-	return FromCgroupV1()
-}
-
-// FromCgroupV2 returns the memory limit from the cgroup v2.
-func FromCgroupV2() (uint64, error) {
-	return fromCgroupV2(cgroupMountPoint)
-}
-
-func fromCgroupV2(mountPoint string) (uint64, error) {
-	path, err := cgroup2.NestedGroupPath("")
-	if err != nil {
-		return 0, err
-	}
-
-	m, err := cgroup2.Load(path, cgroup2.WithMountpoint(mountPoint))
-	if err != nil {
-		return 0, err
-	}
-
-	stats, err := m.Stat()
-	if err != nil {
-		return 0, err
-	}
-
-	if limit := stats.GetMemory().GetUsageLimit(); limit != 0 {
-		return limit, nil
-	}
-
-	return 0, ErrNoLimit
-}

vendor/github.com/KimMachineGun/automemlimit/memlimit/cgroups_linux.go

@@ -0,0 +1,98 @@
+//go:build linux
+// +build linux
+
+package memlimit
+
+import (
+	"math"
+	"os"
+	"path/filepath"
+
+	"github.com/containerd/cgroups/v3"
+	"github.com/containerd/cgroups/v3/cgroup1"
+	"github.com/containerd/cgroups/v3/cgroup2"
+)
+
+const (
+	cgroupMountPoint = "/sys/fs/cgroup"
+)
+
+// FromCgroup returns the memory limit based on the cgroups version on this system.
+func FromCgroup() (uint64, error) {
+	switch cgroups.Mode() {
+	case cgroups.Legacy:
+		return FromCgroupV1()
+	case cgroups.Hybrid:
+		return FromCgroupHybrid()
+	case cgroups.Unified:
+		return FromCgroupV2()
+	}
+	return 0, ErrNoCgroup
+}
+
+// FromCgroupV1 returns the memory limit from the cgroup v1.
+func FromCgroupV1() (uint64, error) {
+	cg, err := cgroup1.Load(cgroup1.RootPath, cgroup1.WithHiearchy(
+		cgroup1.SingleSubsystem(cgroup1.Default, cgroup1.Memory),
+	))
+	if err != nil {
+		return 0, err
+	}
+
+	metrics, err := cg.Stat(cgroup1.IgnoreNotExist)
+	if err != nil {
+		return 0, err
+	}
+
+	if limit := metrics.GetMemory().GetHierarchicalMemoryLimit(); limit != 0 && limit != getCgroupV1NoLimit() {
+		return limit, nil
+	}
+
+	return 0, ErrNoLimit
+}
+
+func getCgroupV1NoLimit() uint64 {
+	ps := uint64(os.Getpagesize())
+	return math.MaxInt64 / ps * ps
+}
+
+// FromCgroupHybrid returns the memory limit from the cgroup v1 or v2.
+// It checks the cgroup v2 first, and if it fails, it falls back to cgroup v1.
+func FromCgroupHybrid() (uint64, error) {
+	limit, err := fromCgroupV2(filepath.Join(cgroupMountPoint, "unified"))
+	if err == nil {
+		return limit, nil
+	} else if err != ErrNoLimit {
+		return 0, err
+	}
+
+	return FromCgroupV1()
+}
+
+// FromCgroupV2 returns the memory limit from the cgroup v2.
+func FromCgroupV2() (uint64, error) {
+	return fromCgroupV2(cgroupMountPoint)
+}
+
+func fromCgroupV2(mountPoint string) (uint64, error) {
+	path, err := cgroup2.NestedGroupPath("")
+	if err != nil {
+		return 0, err
+	}
+
+	m, err := cgroup2.Load(path, cgroup2.WithMountpoint(mountPoint))
+	if err != nil {
+		return 0, err
+	}
+
+	stats, err := m.Stat()
+	if err != nil {
+		return 0, err
+	}
+
+	if limit := stats.GetMemory().GetUsageLimit(); limit != 0 && limit != math.MaxUint64 {
+		return limit, nil
+	}
+
+	return 0, ErrNoLimit
+}

vendor/github.com/KimMachineGun/automemlimit/memlimit/exp_system.go

@@ -0,0 +1,14 @@
+package memlimit
+
+import (
+	"github.com/pbnjay/memory"
+)
+
+// FromSystem returns the total memory of the system.
+func FromSystem() (uint64, error) {
+	limit := memory.TotalMemory()
+	if limit == 0 {
+		return 0, ErrNoLimit
+	}
+	return limit, nil
+}

vendor/github.com/KimMachineGun/automemlimit/memlimit/experiment.go

@@ -0,0 +1,59 @@
+package memlimit
+
+import (
+	"fmt"
+	"os"
+	"reflect"
+	"strings"
+)
+
+const (
+	envAUTOMEMLIMIT_EXPERIMENT = "AUTOMEMLIMIT_EXPERIMENT"
+)
+
+// Experiments is a set of experiment flags.
+// It is used to enable experimental features.
+//
+// You can set the flags by setting the environment variable AUTOMEMLIMIT_EXPERIMENT.
+// The value of the environment variable is a comma-separated list of experiment names.
+//
+// The following experiment names are known:
+//
+//   - none: disable all experiments
+//   - system: enable fallback to system memory limit
+type Experiments struct {
+	// System enables fallback to system memory limit.
+	System bool
+}
+
+func parseExperiments() (Experiments, error) {
+	var exp Experiments
+
+	// Create a map of known experiment names.
+	names := make(map[string]func(bool))
+	rv := reflect.ValueOf(&exp).Elem()
+	rt := rv.Type()
+	for i := 0; i < rt.NumField(); i++ {
+		field := rv.Field(i)
+		names[strings.ToLower(rt.Field(i).Name)] = field.SetBool
+	}
+
+	// Parse names.
+	for _, f := range strings.Split(os.Getenv(envAUTOMEMLIMIT_EXPERIMENT), ",") {
+		if f == "" {
+			continue
+		}
+		if f == "none" {
+			exp = Experiments{}
+			continue
+		}
+		val := true
+		set, ok := names[f]
+		if !ok {
+			return Experiments{}, fmt.Errorf("unknown AUTOMEMLIMIT_EXPERIMENT %s", f)
+		}
+		set(val)
+	}
+
+	return exp, nil
+}

vendor/github.com/KimMachineGun/automemlimit/memlimit/memlimit.go

@@ -22,16 +22,11 @@ const (
 var (
 	// ErrNoLimit is returned when the memory limit is not set.
 	ErrNoLimit = errors.New("memory is not limited")
-	// ErrNoCgroup is returned when the process is not in cgroup.
-	ErrNoCgroup = errors.New("process is not in cgroup")
-	// ErrCgroupsNotSupported is returned when the system does not support cgroups.
-	ErrCgroupsNotSupported = errors.New("cgroups is not supported on this system")
 )
 
 type config struct {
 	logger   *log.Logger
 	ratio    float64
-	env      bool
 	provider Provider
 }
 
@@ -50,10 +45,10 @@ func WithRatio(ratio float64) Option {
 // WithEnv configures whether to use environment variables.
 //
 // Default: false
+//
+// Deprecated: currently this does nothing.
 func WithEnv() Option {
-	return func(cfg *config) {
-		cfg.env = true
-	}
+	return func(cfg *config) {}
 }
 
 // WithProvider configures the provider.
@@ -65,17 +60,24 @@ func WithProvider(provider Provider) Option {
 	}
 }
 
-// SetGoMemLimitWithOpts sets GOMEMLIMIT with options.
+// SetGoMemLimitWithOpts sets GOMEMLIMIT with options and environment variables.
+//
+// You can configure how much memory of the cgroup's memory limit to set as GOMEMLIMIT
+// through AUTOMEMLIMIT envrironment variable in the half-open range (0.0,1.0].
+//
+// If AUTOMEMLIMIT is not set, it defaults to 0.9. (10% is the headroom for memory sources the Go runtime is unaware of.)
+// If GOMEMLIMIT is already set or AUTOMEMLIMIT=off, this function does nothing.
+//
+// If AUTOMEMLIMIT_EXPERIMENT is set, it enables experimental features.
+// Please see the documentation of Experiments for more details.
 //
 // Options:
 //   - WithRatio
-//   - WithEnv (see more SetGoMemLimitWithEnv)
 //   - WithProvider
 func SetGoMemLimitWithOpts(opts ...Option) (_ int64, _err error) {
 	cfg := &config{
 		logger:   log.New(io.Discard, "", log.LstdFlags),
 		ratio:    defaultAUTOMEMLIMIT,
-		env:      false,
 		provider: FromCgroup,
 	}
 	if os.Getenv(envAUTOMEMLIMIT_DEBUG) == "true" {
@@ -90,6 +92,15 @@ func SetGoMemLimitWithOpts(opts ...Option) (_ int64, _err error) {
 		}
 	}()
 
+	exps, err := parseExperiments()
+	if err != nil {
+		return 0, fmt.Errorf("failed to parse experiments: %w", err)
+	}
+	if exps.System {
+		cfg.logger.Println("system experiment is enabled: using system memory limit as a fallback")
+		cfg.provider = ApplyFallback(cfg.provider, FromSystem)
+	}
+
 	snapshot := debug.SetMemoryLimit(-1)
 	defer func() {
 		err := recover()
@@ -122,6 +133,10 @@ func SetGoMemLimitWithOpts(opts ...Option) (_ int64, _err error) {
 
 	limit, err := setGoMemLimit(ApplyRatio(cfg.provider, ratio))
 	if err != nil {
+		if errors.Is(err, ErrNoLimit) {
+			cfg.logger.Printf("memory is not limited, skipping: %v\n", err)
+			return 0, nil
+		}
 		return 0, fmt.Errorf("failed to set GOMEMLIMIT: %w", err)
 	}
 
@@ -130,14 +145,8 @@ func SetGoMemLimitWithOpts(opts ...Option) (_ int64, _err error) {
 	return limit, nil
 }
 
-// SetGoMemLimitWithEnv sets GOMEMLIMIT with the value from the environment variable.
-// You can configure how much memory of the cgroup's memory limit to set as GOMEMLIMIT
-// through AUTOMEMLIMIT in the half-open range (0.0,1.0].
-//
-// If AUTOMEMLIMIT is not set, it defaults to 0.9. (10% is the headroom for memory sources the Go runtime is unaware of.)
-// If GOMEMLIMIT is already set or AUTOMEMLIMIT=off, this function does nothing.
 func SetGoMemLimitWithEnv() {
-	_, _ = SetGoMemLimitWithOpts(WithEnv())
+	_, _ = SetGoMemLimitWithOpts()
 }
 
 // SetGoMemLimit sets GOMEMLIMIT with the value from the cgroup's memory limit and given ratio.

vendor/github.com/pbnjay/memory/LICENSE

@@ -0,0 +1,29 @@
+BSD 3-Clause License
+
+Copyright (c) 2017, Jeremy Jay
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of the copyright holder nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/pbnjay/memory/README.md

@@ -0,0 +1,41 @@
+# memory
+
+Package `memory` provides two methods reporting total physical system memory
+accessible to the kernel, and free memory available to the running application.
+
+This package has no external dependency besides the standard library and default operating system tools.
+
+Documentation:
+[![GoDoc](https://godoc.org/github.com/pbnjay/memory?status.svg)](https://godoc.org/github.com/pbnjay/memory)
+
+This is useful for dynamic code to minimize thrashing and other contention, similar to the stdlib `runtime.NumCPU`
+See some history of the proposal at https://github.com/golang/go/issues/21816
+
+
+## Example
+
+```go
+fmt.Printf("Total system memory: %d\n", memory.TotalMemory())
+fmt.Printf("Free memory: %d\n", memory.FreeMemory())
+```
+
+
+## Testing
+
+Tested/working on:
+ - macOS 10.12.6 (16G29), 10.15.7 (19H2)
+ - Windows 10 1511 (10586.1045)
+ - Linux RHEL (3.10.0-327.3.1.el7.x86_64)
+ - Raspberry Pi 3 (ARMv8) on Raspbian, ODROID-C1+ (ARMv7) on Ubuntu, C.H.I.P
+   (ARMv7).
+ - Amazon Linux 2 aarch64 (m6a.large, 4.14.203-156.332.amzn2.aarch64)
+
+Tested on virtual machines:
+ - Windows 7 SP1 386
+ - Debian stretch 386
+ - NetBSD 7.1 amd64 + 386
+ - OpenBSD 6.1 amd64 + 386
+ - FreeBSD 11.1 amd64 + 386
+ - DragonFly BSD 4.8.1 amd64
+
+If you have access to untested systems please test and report success/bugs.

vendor/github.com/pbnjay/memory/doc.go

@@ -0,0 +1,24 @@
+// Package memory provides a single method reporting total system memory
+// accessible to the kernel.
+package memory
+
+// TotalMemory returns the total accessible system memory in bytes.
+//
+// The total accessible memory is installed physical memory size minus reserved
+// areas for the kernel and hardware, if such reservations are reported by
+// the operating system.
+//
+// If accessible memory size could not be determined, then 0 is returned.
+func TotalMemory() uint64 {
+	return sysTotalMemory()
+}
+
+// FreeMemory returns the total free system memory in bytes.
+//
+// The total free memory is installed physical memory size minus reserved
+// areas for other applications running on the same system.
+//
+// If free memory size could not be determined, then 0 is returned.
+func FreeMemory() uint64 {
+	return sysFreeMemory()
+}

vendor/github.com/pbnjay/memory/memory_bsd.go

@@ -0,0 +1,19 @@
+// +build freebsd openbsd dragonfly netbsd
+
+package memory
+
+func sysTotalMemory() uint64 {
+	s, err := sysctlUint64("hw.physmem")
+	if err != nil {
+		return 0
+	}
+	return s
+}
+
+func sysFreeMemory() uint64 {
+	s, err := sysctlUint64("hw.usermem")
+	if err != nil {
+		return 0
+	}
+	return s
+}

vendor/github.com/pbnjay/memory/memory_darwin.go

@@ -0,0 +1,49 @@
+// +build darwin
+
+package memory
+
+import (
+	"os/exec"
+	"regexp"
+	"strconv"
+)
+
+func sysTotalMemory() uint64 {
+	s, err := sysctlUint64("hw.memsize")
+	if err != nil {
+		return 0
+	}
+	return s
+}
+
+func sysFreeMemory() uint64 {
+	cmd := exec.Command("vm_stat")
+	outBytes, err := cmd.Output()
+	if err != nil {
+		return 0
+	}
+
+	rePageSize := regexp.MustCompile("page size of ([0-9]*) bytes")
+	reFreePages := regexp.MustCompile("Pages free: *([0-9]*)\\.")
+
+	// default: page size of 4096 bytes
+	matches := rePageSize.FindSubmatchIndex(outBytes)
+	pageSize := uint64(4096)
+	if len(matches) == 4 {
+		pageSize, err = strconv.ParseUint(string(outBytes[matches[2]:matches[3]]), 10, 64)
+		if err != nil {
+			return 0
+		}
+	}
+
+	// ex: Pages free:                             1126961.
+	matches = reFreePages.FindSubmatchIndex(outBytes)
+	freePages := uint64(0)
+	if len(matches) == 4 {
+		freePages, err = strconv.ParseUint(string(outBytes[matches[2]:matches[3]]), 10, 64)
+		if err != nil {
+			return 0
+		}
+	}
+	return freePages * pageSize
+}

vendor/github.com/pbnjay/memory/memory_linux.go

@@ -0,0 +1,29 @@
+// +build linux
+
+package memory
+
+import "syscall"
+
+func sysTotalMemory() uint64 {
+	in := &syscall.Sysinfo_t{}
+	err := syscall.Sysinfo(in)
+	if err != nil {
+		return 0
+	}
+	// If this is a 32-bit system, then these fields are
+	// uint32 instead of uint64.
+	// So we always convert to uint64 to match signature.
+	return uint64(in.Totalram) * uint64(in.Unit)
+}
+
+func sysFreeMemory() uint64 {
+	in := &syscall.Sysinfo_t{}
+	err := syscall.Sysinfo(in)
+	if err != nil {
+		return 0
+	}
+	// If this is a 32-bit system, then these fields are
+	// uint32 instead of uint64.
+	// So we always convert to uint64 to match signature.
+	return uint64(in.Freeram) * uint64(in.Unit)
+}

vendor/github.com/pbnjay/memory/memory_windows.go

@@ -0,0 +1,60 @@
+// +build windows
+
+package memory
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// omitting a few fields for brevity...
+// https://msdn.microsoft.com/en-us/library/windows/desktop/aa366589(v=vs.85).aspx
+type memStatusEx struct {
+	dwLength     uint32
+	dwMemoryLoad uint32
+	ullTotalPhys uint64
+	ullAvailPhys uint64
+	unused       [5]uint64
+}
+
+func sysTotalMemory() uint64 {
+	kernel32, err := syscall.LoadDLL("kernel32.dll")
+	if err != nil {
+		return 0
+	}
+	// GetPhysicallyInstalledSystemMemory is simpler, but broken on
+	// older versions of windows (and uses this under the hood anyway).
+	globalMemoryStatusEx, err := kernel32.FindProc("GlobalMemoryStatusEx")
+	if err != nil {
+		return 0
+	}
+	msx := &memStatusEx{
+		dwLength: 64,
+	}
+	r, _, _ := globalMemoryStatusEx.Call(uintptr(unsafe.Pointer(msx)))
+	if r == 0 {
+		return 0
+	}
+	return msx.ullTotalPhys
+}
+
+func sysFreeMemory() uint64 {
+	kernel32, err := syscall.LoadDLL("kernel32.dll")
+	if err != nil {
+		return 0
+	}
+	// GetPhysicallyInstalledSystemMemory is simpler, but broken on
+	// older versions of windows (and uses this under the hood anyway).
+	globalMemoryStatusEx, err := kernel32.FindProc("GlobalMemoryStatusEx")
+	if err != nil {
+		return 0
+	}
+	msx := &memStatusEx{
+		dwLength: 64,
+	}
+	r, _, _ := globalMemoryStatusEx.Call(uintptr(unsafe.Pointer(msx)))
+	if r == 0 {
+		return 0
+	}
+	return msx.ullAvailPhys
+}

vendor/github.com/pbnjay/memory/memsysctl.go

@@ -0,0 +1,21 @@
+// +build darwin freebsd openbsd dragonfly netbsd
+
+package memory
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+func sysctlUint64(name string) (uint64, error) {
+	s, err := syscall.Sysctl(name)
+	if err != nil {
+		return 0, err
+	}
+	// hack because the string conversion above drops a \0
+	b := []byte(s)
+	if len(b) < 8 {
+		b = append(b, 0)
+	}
+	return *(*uint64)(unsafe.Pointer(&b[0])), nil
+}

vendor/github.com/pbnjay/memory/stub.go

@@ -0,0 +1,10 @@
+// +build !linux,!darwin,!windows,!freebsd,!dragonfly,!netbsd,!openbsd
+
+package memory
+
+func sysTotalMemory() uint64 {
+	return 0
+}
+func sysFreeMemory() uint64 {
+	return 0
+}

vendor/modules.txt

@@ -68,7 +68,7 @@ codeberg.org/superseriousbusiness/exif-terminator
 # github.com/DmitriyVTitov/size v1.5.0
 ## explicit; go 1.14
 github.com/DmitriyVTitov/size
-# github.com/KimMachineGun/automemlimit v0.4.0
+# github.com/KimMachineGun/automemlimit v0.5.0
 ## explicit; go 1.19
 github.com/KimMachineGun/automemlimit
 github.com/KimMachineGun/automemlimit/memlimit
@@ -418,6 +418,9 @@ github.com/oklog/ulid
 # github.com/opencontainers/runtime-spec v1.0.2
 ## explicit
 github.com/opencontainers/runtime-spec/specs-go
+# github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58
+## explicit; go 1.16
+github.com/pbnjay/memory
 # github.com/pelletier/go-toml/v2 v2.1.1
 ## explicit; go 1.16
 github.com/pelletier/go-toml/v2