mirror of
https://github.com/golang/go
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4ebfa83199
The existing code did not have a clear notion of whether memory has been actually reserved. It checked based on whether in 32-bit mode or 64-bit mode and (on GNU/Linux) the requested address, but it confused the requested address and the returned address. LGTM=rsc R=rsc, dvyukov CC=golang-codereviews, michael.hudson https://golang.org/cl/79610043
83 lines
1.5 KiB
C
83 lines
1.5 KiB
C
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "runtime.h"
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#include "defs_GOOS_GOARCH.h"
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#include "arch_GOARCH.h"
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#include "malloc.h"
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#include "os_GOOS.h"
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extern byte end[];
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static byte *bloc = { end };
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static Lock memlock;
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enum
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{
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Round = PAGESIZE-1
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};
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void*
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runtime·SysAlloc(uintptr nbytes, uint64 *stat)
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{
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uintptr bl;
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runtime·lock(&memlock);
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// Plan 9 sbrk from /sys/src/libc/9sys/sbrk.c
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bl = ((uintptr)bloc + Round) & ~Round;
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if(runtime·brk_((void*)(bl + nbytes)) < 0) {
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runtime·unlock(&memlock);
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return nil;
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}
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bloc = (byte*)bl + nbytes;
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runtime·unlock(&memlock);
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runtime·xadd64(stat, nbytes);
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return (void*)bl;
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}
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void
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runtime·SysFree(void *v, uintptr nbytes, uint64 *stat)
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{
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runtime·xadd64(stat, -(uint64)nbytes);
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runtime·lock(&memlock);
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// from tiny/mem.c
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// Push pointer back if this is a free
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// of the most recent SysAlloc.
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nbytes += (nbytes + Round) & ~Round;
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if(bloc == (byte*)v+nbytes)
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bloc -= nbytes;
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runtime·unlock(&memlock);
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}
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void
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runtime·SysUnused(void *v, uintptr nbytes)
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{
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USED(v, nbytes);
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}
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void
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runtime·SysUsed(void *v, uintptr nbytes)
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{
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USED(v, nbytes);
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}
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void
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runtime·SysMap(void *v, uintptr nbytes, bool reserved, uint64 *stat)
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{
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USED(v, nbytes, reserved, stat);
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}
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void
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runtime·SysFault(void *v, uintptr nbytes)
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{
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USED(v, nbytes);
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}
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void*
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runtime·SysReserve(void *v, uintptr nbytes, bool *reserved)
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{
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USED(v);
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*reserved = true;
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return runtime·SysAlloc(nbytes, &mstats.heap_sys);
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}
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