/*
- * Copyright 2013 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* limitations under the License.
*/
-#include "folly/MemoryMapping.h"
-#include "folly/Format.h"
+#include <folly/MemoryMapping.h>
+
+#include <algorithm>
+#include <functional>
+#include <utility>
+
+#include <folly/Format.h>
+#include <folly/portability/GFlags.h>
+#include <folly/portability/SysMman.h>
+
+#ifdef __linux__
+#include <folly/experimental/io/HugePages.h>
+#endif
#include <fcntl.h>
-#include <sys/mman.h>
#include <sys/types.h>
#include <system_error>
-#include <gflags/gflags.h>
-DEFINE_int64(mlock_chunk_size, 1 << 20, // 1MB
+static constexpr ssize_t kDefaultMlockChunkSize =
+#ifndef _MSC_VER
+ // Linux implementations of unmap/mlock/munlock take a kernel
+ // semaphore and block other threads from doing other memory
+ // operations. Split the operations in chunks.
+ (1 << 20) // 1MB
+#else // _MSC_VER
+ // MSVC doesn't have this problem, and calling munmap many times
+ // with the same address is a bad idea with the windows implementation.
+ (-1)
+#endif // _MSC_VER
+ ;
+
+DEFINE_int64(mlock_chunk_size, kDefaultMlockChunkSize,
"Maximum bytes to mlock/munlock/munmap at once "
- "(will be rounded up to PAGESIZE)");
+ "(will be rounded up to PAGESIZE). Ignored if negative.");
+
+#ifndef MAP_POPULATE
+#define MAP_POPULATE 0
+#endif
namespace folly {
-/* protected constructor */
-MemoryMapping::MemoryMapping()
- : mapStart_(nullptr)
- , mapLength_(0)
- , locked_(false) {
+MemoryMapping::MemoryMapping(MemoryMapping&& other) noexcept {
+ swap(other);
+}
+
+MemoryMapping::MemoryMapping(File file, off_t offset, off_t length,
+ Options options)
+ : file_(std::move(file)),
+ options_(std::move(options)) {
+ CHECK(file_);
+ init(offset, length);
+}
+
+MemoryMapping::MemoryMapping(const char* name, off_t offset, off_t length,
+ Options options)
+ : MemoryMapping(File(name, options.writable ? O_RDWR : O_RDONLY),
+ offset,
+ length,
+ options) { }
+
+MemoryMapping::MemoryMapping(int fd, off_t offset, off_t length,
+ Options options)
+ : MemoryMapping(File(fd), offset, length, options) { }
+
+MemoryMapping::MemoryMapping(AnonymousType, off_t length, Options options)
+ : options_(std::move(options)) {
+ init(0, length);
}
-MemoryMapping::MemoryMapping(File file, off_t offset, off_t length)
- : mapStart_(nullptr)
- , mapLength_(0)
- , locked_(false) {
+namespace {
- init(std::move(file), offset, length, PROT_READ, false);
+#ifdef __linux__
+void getDeviceOptions(dev_t device, off_t& pageSize, bool& autoExtend) {
+ auto ps = getHugePageSizeForDevice(device);
+ if (ps) {
+ pageSize = ps->size;
+ autoExtend = true;
+ }
}
+#else
+inline void getDeviceOptions(dev_t, off_t&, bool&) {}
+#endif
+
+} // namespace
+
+void MemoryMapping::init(off_t offset, off_t length) {
+ const bool grow = options_.grow;
+ const bool anon = !file_;
+ CHECK(!(grow && anon));
-void MemoryMapping::init(File file,
- off_t offset, off_t length,
- int prot,
- bool grow) {
- off_t pageSize = sysconf(_SC_PAGESIZE);
+ off_t& pageSize = options_.pageSize;
+
+ struct stat st;
+
+ // On Linux, hugetlbfs file systems don't require ftruncate() to grow the
+ // file, and (on kernels before 2.6.24) don't even allow it. Also, the file
+ // size is always a multiple of the page size.
+ bool autoExtend = false;
+
+ if (!anon) {
+ // Stat the file
+ CHECK_ERR(fstat(file_.fd(), &st));
+
+ if (pageSize == 0) {
+ getDeviceOptions(st.st_dev, pageSize, autoExtend);
+ }
+ } else {
+ DCHECK(!file_);
+ DCHECK_EQ(offset, 0);
+ CHECK_EQ(pageSize, 0);
+ CHECK_GE(length, 0);
+ }
+
+ if (pageSize == 0) {
+ pageSize = off_t(sysconf(_SC_PAGESIZE));
+ }
+
+ CHECK_GT(pageSize, 0);
+ CHECK_EQ(pageSize & (pageSize - 1), 0); // power of two
CHECK_GE(offset, 0);
// Round down the start of the mapped region
- size_t skipStart = offset % pageSize;
+ off_t skipStart = offset % pageSize;
offset -= skipStart;
- file_ = std::move(file);
mapLength_ = length;
if (mapLength_ != -1) {
mapLength_ += skipStart;
mapLength_ = (mapLength_ + pageSize - 1) / pageSize * pageSize;
}
- // stat the file
- struct stat st;
- CHECK_ERR(fstat(file_.fd(), &st));
- off_t remaining = st.st_size - offset;
+ off_t remaining = anon ? length : st.st_size - offset;
+
if (mapLength_ == -1) {
length = mapLength_ = remaining;
} else {
if (length > remaining) {
if (grow) {
- PCHECK(0 == ftruncate(file_.fd(), offset + length))
- << "ftructate() failed, couldn't grow file";
- remaining = length;
+ if (!autoExtend) {
+ PCHECK(0 == ftruncate(file_.fd(), offset + length))
+ << "ftruncate() failed, couldn't grow file to "
+ << offset + length;
+ remaining = length;
+ } else {
+ // Extend mapping to multiple of page size, don't use ftruncate
+ remaining = mapLength_;
+ }
} else {
length = remaining;
}
}
- if (mapLength_ > remaining) mapLength_ = remaining;
+ if (mapLength_ > remaining) {
+ mapLength_ = remaining;
+ }
}
if (length == 0) {
mapLength_ = 0;
mapStart_ = nullptr;
} else {
- unsigned char* start = static_cast<unsigned char*>(
- mmap(nullptr, mapLength_, prot, MAP_SHARED, file_.fd(), offset));
+ int flags = options_.shared ? MAP_SHARED : MAP_PRIVATE;
+ if (anon) flags |= MAP_ANONYMOUS;
+ if (options_.prefault) flags |= MAP_POPULATE;
+
+ // The standard doesn't actually require PROT_NONE to be zero...
+ int prot = PROT_NONE;
+ if (options_.readable || options_.writable) {
+ prot = ((options_.readable ? PROT_READ : 0) |
+ (options_.writable ? PROT_WRITE : 0));
+ }
+
+ unsigned char* start = static_cast<unsigned char*>(mmap(
+ options_.address, size_t(mapLength_), prot, flags, file_.fd(), offset));
PCHECK(start != MAP_FAILED)
<< " offset=" << offset
<< " length=" << mapLength_;
mapStart_ = start;
- data_.reset(start + skipStart, length);
+ data_.reset(start + skipStart, size_t(length));
}
}
namespace {
-off_t memOpChunkSize(off_t length) {
+off_t memOpChunkSize(off_t length, off_t pageSize) {
off_t chunkSize = length;
if (FLAGS_mlock_chunk_size <= 0) {
return chunkSize;
}
- chunkSize = FLAGS_mlock_chunk_size;
- off_t pageSize = sysconf(_SC_PAGESIZE);
+ chunkSize = off_t(FLAGS_mlock_chunk_size);
off_t r = chunkSize % pageSize;
if (r) {
chunkSize += (pageSize - r);
* - failure: false + amountSucceeded == nr bytes on which op succeeded.
*/
bool memOpInChunks(std::function<int(void*, size_t)> op,
- void* mem, size_t bufSize,
+ void* mem, size_t bufSize, off_t pageSize,
size_t& amountSucceeded) {
- // unmap/mlock/munlock take a kernel semaphore and block other threads from
- // doing other memory operations. If the size of the buffer is big the
+ // Linux' unmap/mlock/munlock take a kernel semaphore and block other threads
+ // from doing other memory operations. If the size of the buffer is big the
// semaphore can be down for seconds (for benchmarks see
// http://kostja-osipov.livejournal.com/42963.html). Doing the operations in
// chunks breaks the locking into intervals and lets other threads do memory
// operations of their own.
- size_t chunkSize = memOpChunkSize(bufSize);
+ size_t chunkSize = size_t(memOpChunkSize(off_t(bufSize), pageSize));
char* addr = static_cast<char*>(mem);
amountSucceeded = 0;
bool MemoryMapping::mlock(LockMode lock) {
size_t amountSucceeded = 0;
- locked_ = memOpInChunks(::mlock, mapStart_, mapLength_, amountSucceeded);
+ locked_ = memOpInChunks(
+ ::mlock,
+ mapStart_,
+ size_t(mapLength_),
+ options_.pageSize,
+ amountSucceeded);
if (locked_) {
return true;
}
- auto msg(folly::format(
- "mlock({}) failed at {}",
- mapLength_, amountSucceeded).str());
-
- if (lock == LockMode::TRY_LOCK && (errno == EPERM || errno == ENOMEM)) {
+ auto msg =
+ folly::format("mlock({}) failed at {}", mapLength_, amountSucceeded);
+ if (lock == LockMode::TRY_LOCK && errno == EPERM) {
PLOG(WARNING) << msg;
+ } else if (lock == LockMode::TRY_LOCK && errno == ENOMEM) {
+ VLOG(1) << msg;
} else {
PLOG(FATAL) << msg;
}
// only part of the buffer was mlocked, unlock it back
- if (!memOpInChunks(::munlock, mapStart_, amountSucceeded, amountSucceeded)) {
+ if (!memOpInChunks(::munlock, mapStart_, amountSucceeded, options_.pageSize,
+ amountSucceeded)) {
PLOG(WARNING) << "munlock()";
}
if (!locked_) return;
size_t amountSucceeded = 0;
- if (!memOpInChunks(::munlock, mapStart_, mapLength_, amountSucceeded)) {
+ if (!memOpInChunks(
+ ::munlock,
+ mapStart_,
+ size_t(mapLength_),
+ options_.pageSize,
+ amountSucceeded)) {
PLOG(WARNING) << "munlock()";
}
if (mapLength_ && dontneed &&
- ::madvise(mapStart_, mapLength_, MADV_DONTNEED)) {
+ ::madvise(mapStart_, size_t(mapLength_), MADV_DONTNEED)) {
PLOG(WARNING) << "madvise()";
}
locked_ = false;
MemoryMapping::~MemoryMapping() {
if (mapLength_) {
size_t amountSucceeded = 0;
- if (!memOpInChunks(::munmap, mapStart_, mapLength_, amountSucceeded)) {
- PLOG(FATAL) << folly::format(
- "munmap({}) failed at {}",
- mapLength_, amountSucceeded).str();
+ if (!memOpInChunks(
+ ::munmap,
+ mapStart_,
+ size_t(mapLength_),
+ options_.pageSize,
+ amountSucceeded)) {
+ PLOG(FATAL) << folly::format("munmap({}) failed at {}",
+ mapLength_, amountSucceeded);
}
}
}
void MemoryMapping::advise(int advice) const {
- if (mapLength_ && ::madvise(mapStart_, mapLength_, advice)) {
- PLOG(WARNING) << "madvise()";
+ advise(advice, 0, size_t(mapLength_));
+}
+
+void MemoryMapping::advise(int advice, size_t offset, size_t length) const {
+ CHECK_LE(offset + length, size_t(mapLength_))
+ << " offset: " << offset
+ << " length: " << length
+ << " mapLength_: " << mapLength_;
+
+ // Include the entire start page: round down to page boundary.
+ const auto offMisalign = offset % options_.pageSize;
+ offset -= offMisalign;
+ length += offMisalign;
+
+ // Round the last page down to page boundary.
+ if (offset + length != size_t(mapLength_)) {
+ length -= length % options_.pageSize;
+ }
+
+ if (length == 0) {
+ return;
}
+
+ char* mapStart = static_cast<char*>(mapStart_) + offset;
+ PLOG_IF(WARNING, ::madvise(mapStart, length, advice)) << "madvise";
+}
+
+MemoryMapping& MemoryMapping::operator=(MemoryMapping other) {
+ swap(other);
+ return *this;
}
-WritableMemoryMapping::WritableMemoryMapping(File file, off_t offset, off_t length) {
- init(std::move(file), offset, length, PROT_READ | PROT_WRITE, true);
+void MemoryMapping::swap(MemoryMapping& other) noexcept {
+ using std::swap;
+ swap(this->file_, other.file_);
+ swap(this->mapStart_, other.mapStart_);
+ swap(this->mapLength_, other.mapLength_);
+ swap(this->options_, other.options_);
+ swap(this->locked_, other.locked_);
+ swap(this->data_, other.data_);
+}
+
+void swap(MemoryMapping& a, MemoryMapping& b) noexcept { a.swap(b); }
+
+void alignedForwardMemcpy(void* dst, const void* src, size_t size) {
+ assert(reinterpret_cast<uintptr_t>(src) % alignof(unsigned long) == 0);
+ assert(reinterpret_cast<uintptr_t>(dst) % alignof(unsigned long) == 0);
+
+ auto srcl = static_cast<const unsigned long*>(src);
+ auto dstl = static_cast<unsigned long*>(dst);
+
+ while (size >= sizeof(unsigned long)) {
+ *dstl++ = *srcl++;
+ size -= sizeof(unsigned long);
+ }
+
+ auto srcc = reinterpret_cast<const unsigned char*>(srcl);
+ auto dstc = reinterpret_cast<unsigned char*>(dstl);
+
+ while (size != 0) {
+ *dstc++ = *srcc++;
+ --size;
+ }
+}
+
+void mmapFileCopy(const char* src, const char* dest, mode_t mode) {
+ MemoryMapping srcMap(src);
+ srcMap.hintLinearScan();
+
+ MemoryMapping destMap(
+ File(dest, O_RDWR | O_CREAT | O_TRUNC, mode),
+ 0,
+ off_t(srcMap.range().size()),
+ MemoryMapping::writable());
+
+ alignedForwardMemcpy(destMap.writableRange().data(),
+ srcMap.range().data(),
+ srcMap.range().size());
}
} // namespace folly
projects / folly.git / blobdiff