NextGraph
/
rocksdb
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix multiple issues with WinMmapFile fo sequential writing (#1108)

Browse Source 
make preallocation inline with other writable files
  make sure that we map no more than pre-allocated size.
main
Dmitri Smirnov 9 years ago committed by Siying Dong
parent f3bb024fd6
commit 4ea6e051ee
1 changed files with 84 additions and 100 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Show Stats Download Patch File Download Diff File
  1. 150
      port/win/env_win.cc

150
port/win/env_win.cc
Unescape View File

@ -262,8 +262,11 @@ class WinMmapFile : public WritableFile {
// page size or SSD page size
const size_t
allocation_granularity_; // View must start at such a granularity
size_t mapping_size_; // We want file mapping to be of a specific size
// because then the file is expandable
size_t reserved_size_; // Preallocated size
size_t mapping_size_; // The max size of the mapping object
// we want to guess the final file size to minimize the remapping
size_t view_size_; // How much memory to map into a view at a time
char* mapped_begin_; // Must begin at the file offset that is aligned with
@ -283,15 +286,6 @@ class WinMmapFile : public WritableFile {
return ftruncate(filename_, hFile_, toSize);
}
// Can only truncate or reserve to a sector size aligned if
// used on files that are opened with Unbuffered I/O
// Normally it does not present a problem since in memory mapped files
// we do not disable buffering
Status ReserveFileSpace(uint64_t toSize) {
IOSTATS_TIMER_GUARD(allocate_nanos);
return fallocate(filename_, hFile_, toSize);
}
Status UnmapCurrentRegion() {
Status status;
@ -301,75 +295,50 @@ class WinMmapFile : public WritableFile {
"Failed to unmap file view: " + filename_, GetLastError());
}
// Move on to the next portion of the file
file_offset_ += view_size_;
// UnmapView automatically sends data to disk but not the metadata
// which is good and provides some equivalent of fdatasync() on Linux
// therefore, we donot need separate flag for metadata
pending_sync_ = false;
mapped_begin_ = nullptr;
mapped_end_ = nullptr;
dst_ = nullptr;
last_sync_ = nullptr;
// Move on to the next portion of the file
file_offset_ += view_size_;
// Increase the amount we map the next time, but capped at 1MB
view_size_ *= 2;
view_size_ = std::min(view_size_, c_OneMB);
last_sync_ = nullptr;
pending_sync_ = false;
}
return status;
}
Status MapNewRegion() {
Status status;
assert(mapped_begin_ == nullptr);
size_t minMappingSize = file_offset_ + view_size_;
// Check if we need to create a new mapping since we want to write beyond
// the current one
// If the mapping view is now too short
// CreateFileMapping will extend the size of the file automatically if the
// mapping size is greater than
// the current length of the file, which reserves the space and makes
// writing faster, except, windows can not map an empty file.
// Thus the first time around we must actually extend the file ourselves
if (hMap_ == NULL || minMappingSize > mapping_size_) {
if (NULL == hMap_) {
// Creating mapping for the first time so reserve the space on disk
status = ReserveFileSpace(minMappingSize);
size_t minDiskSize = file_offset_ + view_size_;
if (minDiskSize > reserved_size_) {
status = Allocate(file_offset_, view_size_);
if (!status.ok()) {
return status;
}
}
if (hMap_) {
// Need to remap
if (hMap_ == NULL || reserved_size_ > mapping_size_) {
if (hMap_ != NULL) {
// Unmap the previous one
BOOL ret = ::CloseHandle(hMap_);
assert(ret);
hMap_ = NULL;
}
// Calculate the new mapping size which will hopefully reserve space for
// several consecutive sliding views
// Query preallocation block size if set
size_t preallocationBlockSize = 0;
size_t lastAllocatedBlockSize = 0; // Not used
GetPreallocationStatus(&preallocationBlockSize, &lastAllocatedBlockSize);
if (preallocationBlockSize) {
preallocationBlockSize =
Roundup(preallocationBlockSize, allocation_granularity_);
} else {
preallocationBlockSize = 2 * view_size_;
}
mapping_size_ += preallocationBlockSize;
ULARGE_INTEGER mappingSize;
mappingSize.QuadPart = mapping_size_;
mappingSize.QuadPart = reserved_size_;
hMap_ = CreateFileMappingA(
hFile_,
@ -385,6 +354,8 @@ class WinMmapFile : public WritableFile {
"WindowsMmapFile failed to create file mapping for: " + filename_,
GetLastError());
}
mapping_size_ = reserved_size_;
}
ULARGE_INTEGER offset;
@ -416,6 +387,7 @@ class WinMmapFile : public WritableFile {
hMap_(NULL),
page_size_(page_size),
allocation_granularity_(allocation_granularity),
reserved_size_(0),
mapping_size_(0),
view_size_(0),
mapped_begin_(nullptr),
@ -435,25 +407,10 @@ class WinMmapFile : public WritableFile {
// Only for memory mapped writes
assert(options.use_mmap_writes);
// Make sure buffering is not disabled. It is ignored for mapping
// purposes but also imposes restriction on moving file position
// it is not a problem so much with reserving space since it is probably a
// factor
// of allocation_granularity but we also want to truncate the file in
// Close() at
// arbitrary position so we do not have to feel this with zeros.
assert(options.use_os_buffer);
// View size must be both the multiple of allocation_granularity AND the
// page size
if ((allocation_granularity_ % page_size_) == 0) {
view_size_ = 2 * allocation_granularity;
} else if ((page_size_ % allocation_granularity_) == 0) {
view_size_ = 2 * page_size_;
} else {
// we can multiply them together
assert(false);
}
// page size and the granularity is usually a multiple of a page size.
const size_t viewSize = 32 * 1024; // 32Kb similar to the Windows File Cache in buffered mode
view_size_ = Roundup(viewSize, allocation_granularity_);
}
~WinMmapFile() {
@ -479,8 +436,7 @@ class WinMmapFile : public WritableFile {
if (!s.ok()) {
return s;
}
}
} else {
size_t n = std::min(left, avail);
memcpy(dst_, src, n);
dst_ += n;
@ -488,6 +444,13 @@ class WinMmapFile : public WritableFile {
left -= n;
pending_sync_ = true;
}
}
// Now make sure that the last partial page is padded with zeros if needed
size_t bytesToPad = Roundup(size_t(dst_), page_size_) - size_t(dst_);
if (bytesToPad > 0) {
memset(dst_, 0, bytesToPad);
}
return Status::OK();
}
@ -508,7 +471,13 @@ class WinMmapFile : public WritableFile {
// which we use does not write zeros and it is good.
uint64_t targetSize = GetFileSize();
if (mapped_begin_ != nullptr) {
// Sync before unmapping to make sure everything
// is on disk and there is not a lazy writing
// so we are deterministic with the tests
Sync();
s = UnmapCurrentRegion();
}
if (NULL != hMap_) {
BOOL ret = ::CloseHandle(hMap_);
@ -521,6 +490,8 @@ class WinMmapFile : public WritableFile {
hMap_ = NULL;
}
if (hFile_ != NULL) {
TruncateFile(targetSize);
BOOL ret = ::CloseHandle(hFile_);
@ -531,6 +502,7 @@ class WinMmapFile : public WritableFile {
s = IOErrorFromWindowsError(
"Failed to close file map handle: " + filename_, lastError);
}
}
return s;
}
@ -542,7 +514,7 @@ class WinMmapFile : public WritableFile {
Status s;
// Some writes occurred since last sync
if (pending_sync_) {
if (dst_ > last_sync_) {
assert(mapped_begin_);
assert(dst_);
assert(dst_ > mapped_begin_);
@ -552,16 +524,15 @@ class WinMmapFile : public WritableFile {
TruncateToPageBoundary(page_size_, last_sync_ - mapped_begin_);
size_t page_end =
TruncateToPageBoundary(page_size_, dst_ - mapped_begin_ - 1);
last_sync_ = dst_;
// Flush only the amount of that is a multiple of pages
if (!::FlushViewOfFile(mapped_begin_ + page_begin,
(page_end - page_begin) + page_size_)) {
s = IOErrorFromWindowsError("Failed to FlushViewOfFile: " + filename_,
GetLastError());
} else {
last_sync_ = dst_;
}
pending_sync_ = false;
}
return s;
@ -571,19 +542,15 @@ class WinMmapFile : public WritableFile {
* Flush data as well as metadata to stable storage.
*/
virtual Status Fsync() override {
Status s;
// Flush metadata if pending
const bool pending = pending_sync_;
s = Sync();
Status s = Sync();
// Flush metadata
if (s.ok() && pending) {
if (s.ok() && pending_sync_) {
if (!::FlushFileBuffers(hFile_)) {
s = IOErrorFromWindowsError("Failed to FlushFileBuffers: " + filename_,
GetLastError());
}
pending_sync_ = false;
}
return s;
@ -604,7 +571,24 @@ class WinMmapFile : public WritableFile {
}
virtual Status Allocate(uint64_t offset, uint64_t len) override {
return Status::OK();
Status status;
TEST_KILL_RANDOM("WinMmapFile::Allocate", rocksdb_kill_odds);
// Make sure that we reserve an aligned amount of space
// since the reservation block size is driven outside so we want
// to check if we are ok with reservation here
size_t spaceToReserve = Roundup(offset + len, view_size_);
// Nothing to do
if (spaceToReserve <= reserved_size_) {
return status;
}
IOSTATS_TIMER_GUARD(allocate_nanos);
status = fallocate(filename_, hFile_, spaceToReserve);
if (status.ok()) {
reserved_size_ = spaceToReserve;
}
return status;
}
};

Write Preview
Loading…
Cancel
Save