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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/MemUtils.h"
#if defined(XP_WIN)
# include <windows.h>
# include "mozilla/Maybe.h"
#else
# include <sys/mman.h>
#endif
#if defined(XP_WIN)
typedef BOOL(WINAPI* PrefetchVirtualMemoryFn)(HANDLE, ULONG_PTR, PVOID, ULONG);
static mozilla::Maybe<PrefetchVirtualMemoryFn> sPrefetchVirtualMemory;
void MaybeInitPrefetchVirtualMemory() {
if (sPrefetchVirtualMemory.isNothing()) {
sPrefetchVirtualMemory.emplace(
reinterpret_cast<PrefetchVirtualMemoryFn>(GetProcAddress(
GetModuleHandleW(L"kernel32.dll"), "PrefetchVirtualMemory")));
}
}
#endif
bool mozilla::CanPrefetchMemory() {
#if defined(XP_SOLARIS) || defined(XP_UNIX)
return true;
#elif defined(XP_WIN)
MaybeInitPrefetchVirtualMemory();
return *sPrefetchVirtualMemory;
#else
return false;
#endif
}
void mozilla::PrefetchMemory(uint8_t* aStart, size_t aNumBytes) {
if (aNumBytes == 0) {
return;
}
#if defined(XP_SOLARIS)
posix_madvise(aStart, aNumBytes, POSIX_MADV_WILLNEED);
#elif defined(XP_UNIX)
madvise(aStart, aNumBytes, MADV_WILLNEED);
#elif defined(XP_WIN)
MaybeInitPrefetchVirtualMemory();
if (*sPrefetchVirtualMemory) {
// Normally, we'd use WIN32_MEMORY_RANGE_ENTRY, but that requires
// a different _WIN32_WINNT value before including windows.h, but
// that causes complications with unified sources. It's a simple
// enough struct anyways.
struct {
PVOID VirtualAddress;
SIZE_T NumberOfBytes;
} entry;
entry.VirtualAddress = aStart;
entry.NumberOfBytes = aNumBytes;
(*sPrefetchVirtualMemory)(GetCurrentProcess(), 1, &entry, 0);
return;
}
#endif
}
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