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rocksdb/port/mmap.cc

99 lines
2.4 KiB

// Copyright (c) Meta Platforms, Inc. and affiliates.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "port/mmap.h"
#include <cassert>
#include <cstdio>
#include <cstring>
#include <new>
#include <utility>
#include "util/hash.h"
namespace ROCKSDB_NAMESPACE {
MemMapping::~MemMapping() {
#ifdef OS_WIN
if (addr_ != nullptr) {
(void)::UnmapViewOfFile(addr_);
}
if (page_file_handle_ != NULL) {
(void)::CloseHandle(page_file_handle_);
}
#else // OS_WIN -> !OS_WIN
if (addr_ != nullptr) {
auto status = munmap(addr_, length_);
assert(status == 0);
if (status != 0) {
// TODO: handle error?
}
}
#endif // OS_WIN
}
MemMapping::MemMapping(MemMapping&& other) noexcept {
*this = std::move(other);
}
MemMapping& MemMapping::operator=(MemMapping&& other) noexcept {
if (&other == this) {
return *this;
}
this->~MemMapping();
std::memcpy(this, &other, sizeof(*this));
new (&other) MemMapping();
return *this;
}
MemMapping MemMapping::AllocateAnonymous(size_t length, bool huge) {
MemMapping mm;
mm.length_ = length;
assert(mm.addr_ == nullptr);
if (length == 0) {
// OK to leave addr as nullptr
return mm;
}
int huge_flag = 0;
#ifdef OS_WIN
if (huge) {
#ifdef FILE_MAP_LARGE_PAGES
huge_flag = FILE_MAP_LARGE_PAGES;
#endif // FILE_MAP_LARGE_PAGES
}
mm.page_file_handle_ = ::CreateFileMapping(
INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE | SEC_COMMIT,
Upper32of64(length), Lower32of64(length), nullptr);
if (mm.page_file_handle_ == NULL) {
// Failure
return mm;
}
mm.addr_ = ::MapViewOfFile(mm.page_file_handle_, FILE_MAP_WRITE | huge_flag,
0, 0, length);
#else // OS_WIN -> !OS_WIN
if (huge) {
#ifdef MAP_HUGETLB
huge_flag = MAP_HUGETLB;
#endif // MAP_HUGE_TLB
}
mm.addr_ = mmap(nullptr, length, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | huge_flag, -1, 0);
if (mm.addr_ == MAP_FAILED) {
mm.addr_ = nullptr;
}
#endif // OS_WIN
return mm;
}
MemMapping MemMapping::AllocateHuge(size_t length) {
return AllocateAnonymous(length, /*huge*/ true);
}
MemMapping MemMapping::AllocateLazyZeroed(size_t length) {
return AllocateAnonymous(length, /*huge*/ false);
}
} // namespace ROCKSDB_NAMESPACE