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https://github.com/golang/go
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65 lines
1.4 KiB
C
65 lines
1.4 KiB
C
// Copyright 2009 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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// Trivial base allocator.
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#include "malloc.h"
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// TODO: The call to sys·mmap should be a call to an assembly
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// function sys·mmapnew that takes only a size parameter.
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enum
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{
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PROT_NONE = 0x00,
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PROT_READ = 0x01,
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PROT_WRITE = 0x02,
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PROT_EXEC = 0x04,
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MAP_FILE = 0x0000,
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MAP_SHARED = 0x0001,
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MAP_PRIVATE = 0x0002,
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MAP_FIXED = 0x0010,
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MAP_ANON = 0x1000,
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};
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// Allocate and return zeroed memory.
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// Simple allocator for small things like Span structures,
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// and also used to grab large amounts of memory for
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// the real allocator to hand out.
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enum
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{
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Round = 15,
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};
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void*
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trivalloc(int32 size)
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{
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static byte *p;
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static int32 n;
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byte *v;
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if(allocator·frozen)
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throw("allocator frozen");
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//prints("Newmem: ");
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//sys·printint(size);
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//prints("\n");
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if(size < 4096) { // TODO: Tune constant.
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size = (size + Round) & ~Round;
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if(size > n) {
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n = 1<<20; // TODO: Tune constant.
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p = sys·mmap(nil, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, 0, 0);
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allocator·footprint += n;
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}
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v = p;
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p += size;
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return v;
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}
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if(size & PageMask)
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size += (1<<PageShift) - (size & PageMask);
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v = sys·mmap(nil, size, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, 0, 0);
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allocator·footprint += size;
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return v;
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}
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