Automatically set GOMEMLIMIT at 90% of available memory.

Or at the ratio specified by `AUTOMEMLIMIT`.

go.mod

@@ -3,6 +3,7 @@ module whitequark.org/git-pages
 go 1.25.0
 
 require (
+	github.com/KimMachineGun/automemlimit v0.7.4
 	github.com/go-git/go-git/v6 v6.0.0-20250910120214-3a68d0404116
 	github.com/maypok86/otter/v2 v2.2.1
 	github.com/minio/minio-go/v7 v7.0.95
@@ -29,6 +30,7 @@ require (
 	github.com/klauspost/cpuid/v2 v2.3.0 // indirect
 	github.com/minio/crc64nvme v1.0.2 // indirect
 	github.com/minio/md5-simd v1.1.2 // indirect
+	github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58 // indirect
 	github.com/philhofer/fwd v1.2.0 // indirect
 	github.com/pjbgf/sha1cd v0.5.0 // indirect
 	github.com/rs/xid v1.6.0 // indirect

go.sum

@@ -1,5 +1,7 @@
 dario.cat/mergo v1.0.1 h1:Ra4+bf83h2ztPIQYNP99R6m+Y7KfnARDfID+a+vLl4s=
 dario.cat/mergo v1.0.1/go.mod h1:uNxQE+84aUszobStD9th8a29P2fMDhsBdgRYvZOxGmk=
+github.com/KimMachineGun/automemlimit v0.7.4 h1:UY7QYOIfrr3wjjOAqahFmC3IaQCLWvur9nmfIn6LnWk=
+github.com/KimMachineGun/automemlimit v0.7.4/go.mod h1:QZxpHaGOQoYvFhv/r4u3U0JTC2ZcOwbSr11UZF46UBM=
 github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
 github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
 github.com/ProtonMail/go-crypto v1.3.0 h1:ILq8+Sf5If5DCpHQp4PbZdS1J7HDFRXz/+xKBiRGFrw=
@@ -59,6 +61,8 @@ github.com/minio/md5-simd v1.1.2 h1:Gdi1DZK69+ZVMoNHRXJyNcxrMA4dSxoYHZSQbirFg34=
 github.com/minio/md5-simd v1.1.2/go.mod h1:MzdKDxYpY2BT9XQFocsiZf/NKVtR7nkE4RoEpN+20RM=
 github.com/minio/minio-go/v7 v7.0.95 h1:ywOUPg+PebTMTzn9VDsoFJy32ZuARN9zhB+K3IYEvYU=
 github.com/minio/minio-go/v7 v7.0.95/go.mod h1:wOOX3uxS334vImCNRVyIDdXX9OsXDm89ToynKgqUKlo=
+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 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
 github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
 github.com/philhofer/fwd v1.2.0 h1:e6DnBTl7vGY+Gz322/ASL4Gyp1FspeMvx1RNDoToZuM=

src/main.go

@@ -3,10 +3,13 @@ package main
 import (
 	"flag"
 	"log"
+	"log/slog"
 	"net"
 	"net/http"
 	"os"
 	"strings"
+
+	"github.com/KimMachineGun/automemlimit/memlimit"
 )
 
 var backend Backend
@@ -84,6 +87,18 @@ func main() {
 		log.Println("migrate v1 ok")
 	}
 
+	// Avoid being OOM killed by not garbage collecting early enough.
+	memlimit.SetGoMemLimitWithOpts(
+		memlimit.WithLogger(slog.Default()),
+		memlimit.WithProvider(
+			memlimit.ApplyFallback(
+				memlimit.FromCgroup,
+				memlimit.FromSystem,
+			),
+		),
+		memlimit.WithRatio(0.9),
+	)
+
 	log.Println("ready")
 
 	go serveHandler("pages", config.Listen.Pages, ServePages)