root/src/pkg/runtime/mem_plan9.c

DEFINITIONS

1. runtime·SysAlloc
2. runtime·SysFree
3. runtime·SysUnused
4. runtime·SysUsed
5. runtime·SysMap
6. runtime·SysFault
7. runtime·SysReserve

// Copyright 2010 The Go Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include "runtime.h"
#include "defs_GOOS_GOARCH.h"
#include "arch_GOARCH.h"
#include "malloc.h"
#include "os_GOOS.h"

extern byte end[];
static byte *bloc = { end };
static Lock memlock;

enum
{
        Round = PAGESIZE-1
};

void*
runtime·SysAlloc(uintptr nbytes, uint64 *stat)
{
        uintptr bl;

        runtime·lock(&memlock);
        // Plan 9 sbrk from /sys/src/libc/9sys/sbrk.c
        bl = ((uintptr)bloc + Round) & ~Round;
        if(runtime·brk_((void*)(bl + nbytes)) < 0) {
                runtime·unlock(&memlock);
                return nil;
        }
        bloc = (byte*)bl + nbytes;
        runtime·unlock(&memlock);
        runtime·xadd64(stat, nbytes);
        return (void*)bl;
}

void
runtime·SysFree(void *v, uintptr nbytes, uint64 *stat)
{
        runtime·xadd64(stat, -(uint64)nbytes);
        runtime·lock(&memlock);
        // from tiny/mem.c
        // Push pointer back if this is a free
        // of the most recent SysAlloc.
        nbytes += (nbytes + Round) & ~Round;
        if(bloc == (byte*)v+nbytes)
                bloc -= nbytes;
        runtime·unlock(&memlock);
}

void
runtime·SysUnused(void *v, uintptr nbytes)
{
        USED(v, nbytes);
}

void
runtime·SysUsed(void *v, uintptr nbytes)
{
        USED(v, nbytes);
}

void
runtime·SysMap(void *v, uintptr nbytes, bool reserved, uint64 *stat)
{
        USED(v, nbytes, reserved, stat);
}

void
runtime·SysFault(void *v, uintptr nbytes)
{
        USED(v, nbytes);
}

void*
runtime·SysReserve(void *v, uintptr nbytes, bool *reserved)
{
        USED(v);
        *reserved = true;
        return runtime·SysAlloc(nbytes, &mstats.heap_sys);
}