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1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "base/trace_event/memory_profiler_allocation_register.h" | |
6 | |
7 #include <sys/mman.h> | |
8 #include <unistd.h> | |
9 | |
10 #include "base/basictypes.h" | |
11 #include "base/bits.h" | |
12 #include "base/logging.h" | |
13 #include "base/process/process_metrics.h" | |
14 | |
15 #ifndef MAP_ANONYMOUS | |
16 #define MAP_ANONYMOUS MAP_ANON | |
17 #endif | |
18 | |
19 namespace base { | |
20 namespace trace_event { | |
21 | |
22 namespace { | |
23 size_t GetGuardSize() { | |
24 return GetPageSize(); | |
25 } | |
26 } | |
27 | |
28 // static | |
29 void* AllocationRegister::AllocateVirtualMemory(size_t size) { | |
30 size = bits::Align(size, GetPageSize()); | |
31 | |
32 // Add space for a guard page at the end. | |
33 size_t map_size = size + GetGuardSize(); | |
34 | |
35 void* addr = mmap(nullptr, map_size, PROT_READ | PROT_WRITE, | |
36 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); | |
37 | |
38 PCHECK(addr != MAP_FAILED); | |
39 | |
40 // Mark the last page of the allocated address space as inaccessible | |
41 // (PROT_NONE). The read/write accessible space is still at least |min_size| | |
42 // bytes. | |
43 void* guard_addr = | |
44 reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(addr) + size); | |
45 int result = mprotect(guard_addr, GetGuardSize(), PROT_NONE); | |
46 PCHECK(result == 0); | |
47 | |
48 return addr; | |
49 } | |
50 | |
51 // static | |
52 void AllocationRegister::FreeVirtualMemory(void* address, | |
53 size_t allocated_size) { | |
54 size_t size = bits::Align(allocated_size, GetPageSize()) + GetGuardSize(); | |
55 munmap(address, size); | |
56 } | |
57 | |
58 } // namespace trace_event | |
59 } // namespace base | |
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