| // Copyright 2015 The Chromium 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 "base/trace_event/heap_profiler_allocation_register.h" |
| |
| #include <windows.h> |
| |
| #include "base/bits.h" |
| #include "base/logging.h" |
| #include "base/process/process_metrics.h" |
| |
| namespace base { |
| namespace trace_event { |
| |
| namespace { |
| size_t GetGuardSize() { |
| return GetPageSize(); |
| } |
| } |
| |
| // static |
| void* AllocationRegister::AllocateVirtualMemory(size_t size) { |
| size = bits::Align(size, GetPageSize()); |
| |
| // Add space for a guard page at the end. |
| size_t map_size = size + GetGuardSize(); |
| |
| // Reserve the address space. This does not make the memory usable yet. |
| void* addr = VirtualAlloc(nullptr, map_size, MEM_RESERVE, PAGE_NOACCESS); |
| |
| PCHECK(addr != nullptr); |
| |
| // Commit the non-guard pages as read-write memory. |
| void* result = VirtualAlloc(addr, size, MEM_COMMIT, PAGE_READWRITE); |
| |
| PCHECK(result != nullptr); |
| |
| // Mark the last page of the allocated address space as guard page. (NB: The |
| // |PAGE_GUARD| flag is not the flag to use here, that flag can be used to |
| // detect and intercept access to a certain memory region. Accessing a |
| // |PAGE_NOACCESS| page will raise a general protection fault.) The |
| // read/write accessible space is still at least |min_size| bytes. |
| void* guard_addr = |
| reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(addr) + size); |
| result = VirtualAlloc(guard_addr, GetGuardSize(), MEM_COMMIT, PAGE_NOACCESS); |
| PCHECK(result != nullptr); |
| |
| return addr; |
| } |
| |
| // static |
| void AllocationRegister::FreeVirtualMemory(void* address, |
| size_t allocated_size) { |
| // For |VirtualFree|, the size passed with |MEM_RELEASE| mut be 0. Windows |
| // automatically frees the entire region that was reserved by the |
| // |VirtualAlloc| with flag |MEM_RESERVE|. |
| VirtualFree(address, 0, MEM_RELEASE); |
| } |
| |
| } // namespace trace_event |
| } // namespace base |