purego: use sync.Pool in syscall_syscall15X (#328)

This works around the stack growth issue in 05d8da4 by not marking the function as nosplit.
This commit uses a pool to cache syscall15Args instances. Otherwise a new instance
was allocated on the heap for each purego call.

commit: 6dda16a6f8ed36b52fe7ef10ae40e6d1d4dcde7c
author: oliverbestmann · 14mo ago · 2025-07-30 23:52 UTC
committer: GitHub · 14mo ago · 2025-07-30 23:52 UTC
parent: cdb93a8
signature: GPG UnverifiedB5690EEEBB952194 The key is unknown

1 file · +6 -3

M syscall_sysv.go +6 -3


@@ -14,14 +14,17 @@ import (
14	14
15	15		var syscall15XABI0 uintptr
16	16
17		-	//go:nosplit
18	17		func syscall_syscall15X(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15 uintptr) (r1, r2, err uintptr) {
19		-	args := syscall15Args{
	18	+	args := thePool.Get().(*syscall15Args)
	19	+	defer thePool.Put(args)
	20	+
	21	+	*args = syscall15Args{
20	22		fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15,
21	23		a1, a2, a3, a4, a5, a6, a7, a8,
22	24		0,
23	25		}
24		-	runtime_cgocall(syscall15XABI0, unsafe.Pointer(&args))
	26	+
	27	+	runtime_cgocall(syscall15XABI0, unsafe.Pointer(args))
25	28		return args.a1, args.a2, 0
26	29		}
27	30


@@ -14,14 +14,17 @@ import (
14			14
15		var syscall15XABI0 uintptr	15		var syscall15XABI0 uintptr
16			16
17	-	//go:nosplit
18		func syscall_syscall15X(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15 uintptr) (r1, r2, err uintptr) {	17		func syscall_syscall15X(fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15 uintptr) (r1, r2, err uintptr) {
19	-	args := syscall15Args{	18	+	args := thePool.Get().(*syscall15Args)
			19	+	defer thePool.Put(args)
			20	+
			21	+	*args = syscall15Args{
20		fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15,	22		fn, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15,
21		a1, a2, a3, a4, a5, a6, a7, a8,	23		a1, a2, a3, a4, a5, a6, a7, a8,
22		0,	24		0,
23		}	25		}
24	-	runtime_cgocall(syscall15XABI0, unsafe.Pointer(&args))	26	+
			27	+	runtime_cgocall(syscall15XABI0, unsafe.Pointer(args))
25		return args.a1, args.a2, 0	28		return args.a1, args.a2, 0
26		}	29		}
27			30