1// Copyright 2018 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5package runtime 6 7import ( 8 "unsafe" 9) 10 11// Don't split the stack as this function may be invoked without a valid G, 12// which prevents us from allocating more stack. 13//go:nosplit 14func sysAlloc(n uintptr, sysStat *uint64) unsafe.Pointer { 15 v, err := mmap(nil, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_PRIVATE, -1, 0) 16 if err != 0 { 17 return nil 18 } 19 mSysStatInc(sysStat, n) 20 return v 21} 22 23func sysUnused(v unsafe.Pointer, n uintptr) { 24 // MADV_FREE_REUSABLE is like MADV_FREE except it also propagates 25 // accounting information about the process to task_info. 26 madvise(v, n, _MADV_FREE_REUSABLE) 27} 28 29func sysUsed(v unsafe.Pointer, n uintptr) { 30 // MADV_FREE_REUSE is necessary to keep the kernel's accounting 31 // accurate. If called on any memory region that hasn't been 32 // MADV_FREE_REUSABLE'd, it's a no-op. 33 madvise(v, n, _MADV_FREE_REUSE) 34} 35 36func sysHugePage(v unsafe.Pointer, n uintptr) { 37} 38 39// Don't split the stack as this function may be invoked without a valid G, 40// which prevents us from allocating more stack. 41//go:nosplit 42func sysFree(v unsafe.Pointer, n uintptr, sysStat *uint64) { 43 mSysStatDec(sysStat, n) 44 munmap(v, n) 45} 46 47func sysFault(v unsafe.Pointer, n uintptr) { 48 mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE|_MAP_FIXED, -1, 0) 49} 50 51func sysReserve(v unsafe.Pointer, n uintptr) unsafe.Pointer { 52 p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_PRIVATE, -1, 0) 53 if err != 0 { 54 return nil 55 } 56 return p 57} 58 59const _ENOMEM = 12 60 61func sysMap(v unsafe.Pointer, n uintptr, sysStat *uint64) { 62 mSysStatInc(sysStat, n) 63 64 p, err := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0) 65 if err == _ENOMEM { 66 throw("runtime: out of memory") 67 } 68 if p != v || err != 0 { 69 throw("runtime: cannot map pages in arena address space") 70 } 71} 72