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// @file mongommf.cpp
/**
* Copyright (C) 2010 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* this module adds some of our layers atop memory mapped files - specifically our handling of private views & such
if you don't care about journaling/durability (temp sort files & such) use MemoryMappedFile class, not this.
*/
#include "pch.h"
#include "cmdline.h"
#include "mongommf.h"
#include "dur.h"
#include "dur_journalformat.h"
#include "../util/mongoutils/str.h"
using namespace mongoutils;
namespace mongo {
#if defined(_WIN32)
extern mutex mapViewMutex;
__declspec(noinline) void makeChunkWritable(size_t chunkno) {
scoped_lock lk(mapViewMutex);
if( writable.get(chunkno) ) // double check lock
return;
// remap all maps in this chunk. common case is a single map, but could have more than one with smallfiles or .ns files
size_t chunkStart = chunkno * MemoryMappedFile::ChunkSize;
size_t chunkNext = chunkStart + MemoryMappedFile::ChunkSize;
scoped_lock lk2(privateViews._mutex());
map<void*,MongoMMF*>::iterator i = privateViews.finditer_inlock((void*) (chunkNext-1));
while( 1 ) {
const pair<void*,MongoMMF*> x = *(--i);
MongoMMF *mmf = x.second;
if( mmf == 0 )
break;
size_t viewStart = (size_t) x.first;
size_t viewEnd = viewStart + mmf->length();
if( viewEnd <= chunkStart )
break;
size_t protectStart = max(viewStart, chunkStart);
dassert(protectStart<chunkNext);
size_t protectEnd = min(viewEnd, chunkNext);
size_t protectSize = protectEnd - protectStart;
dassert(protectSize>0&&protectSize<=MemoryMappedFile::ChunkSize);
DWORD old;
bool ok = VirtualProtect((void*)protectStart, protectSize, PAGE_WRITECOPY, &old);
if( !ok ) {
DWORD e = GetLastError();
log() << "VirtualProtect failed " << chunkno << hex << protectStart << ' ' << protectSize << ' ' << errnoWithDescription(e) << endl;
assert(false);
}
}
writable.set(chunkno);
}
__declspec(noinline) void makeChunkWritableOld(size_t chunkno) {
scoped_lock lk(mapViewMutex);
if( writable.get(chunkno) )
return;
size_t loc = chunkno * MemoryMappedFile::ChunkSize;
void *Loc = (void*) loc;
size_t ofs;
MongoMMF *mmf = privateViews.find( (void *) (loc), ofs );
MemoryMappedFile *f = (MemoryMappedFile*) mmf;
assert(f);
size_t len = MemoryMappedFile::ChunkSize;
assert( mmf->getView() <= Loc );
if( ofs + len > f->length() ) {
// at the very end of the map
len = f->length() - ofs;
}
else {
;
}
// todo: check this goes away on remap
DWORD old;
bool ok = VirtualProtect(Loc, len, PAGE_WRITECOPY, &old);
if( !ok ) {
DWORD e = GetLastError();
log() << "VirtualProtect failed " << Loc << ' ' << len << ' ' << errnoWithDescription(e) << endl;
assert(false);
}
writable.set(chunkno);
}
// align so that there is only one map per chunksize so our bitset works right
void* mapaligned(HANDLE h, unsigned long long _len) {
void *loc = 0;
int n = 0;
while( 1 ) {
n++;
void *m = MapViewOfFileEx(h, FILE_MAP_READ, 0, 0, 0, loc);
if( m == 0 ) {
DWORD e = GetLastError();
if( n == 0 ) {
// if first fails, it isn't going to work
log() << "mapaligned errno: " << e << endl;
break;
}
if( debug && n == 1 ) {
log() << "mapaligned info e:" << e << " at n=1" << endl;
}
if( n > 98 ) {
log() << "couldn't align mapped view of file len:" << _len/1024.0/1024.0 << "MB errno:" << e << endl;
break;
}
loc = (void*) (((size_t)loc)+MemoryMappedFile::ChunkSize);
continue;
}
size_t x = (size_t) m;
if( x % MemoryMappedFile::ChunkSize == 0 ) {
void *end = (void*) (x+_len);
DEV log() << "mapaligned " << m << '-' << end << " len:" << _len << endl;
return m;
}
UnmapViewOfFile(m);
x = ((x+MemoryMappedFile::ChunkSize-1) / MemoryMappedFile::ChunkSize) * MemoryMappedFile::ChunkSize;
loc = (void*) x;
if( n % 20 == 0 ) {
log() << "warning mapaligned n=20" << endl;
}
if( n > 100 ) {
log() << "couldn't align mapped view of file len:" << _len/1024.0/1024.0 << "MB" << endl;
break;
}
}
return 0;
}
void* MemoryMappedFile::createPrivateMap() {
assert( maphandle );
scoped_lock lk(mapViewMutex);
//void *p = mapaligned(maphandle, len);
void *p = MapViewOfFile(maphandle, FILE_MAP_READ, 0, 0, 0);
if ( p == 0 ) {
DWORD e = GetLastError();
log() << "createPrivateMap failed " << filename() << " " << errnoWithDescription(e) << endl;
}
else {
clearWritableBits(p);
views.push_back(p);
}
return p;
}
void* MemoryMappedFile::remapPrivateView(void *oldPrivateAddr) {
dbMutex.assertWriteLocked(); // short window where we are unmapped so must be exclusive
// the mapViewMutex is to assure we get the same address on the remap
scoped_lock lk(mapViewMutex);
clearWritableBits(oldPrivateAddr);
if( !UnmapViewOfFile(oldPrivateAddr) ) {
DWORD e = GetLastError();
log() << "UnMapViewOfFile failed " << filename() << ' ' << errnoWithDescription(e) << endl;
assert(false);
}
// we want the new address to be the same as the old address in case things keep pointers around (as namespaceindex does).
void *p = MapViewOfFileEx(maphandle, FILE_MAP_READ, 0, 0,
/*dwNumberOfBytesToMap 0 means to eof*/0 /*len*/,
oldPrivateAddr);
if ( p == 0 ) {
DWORD e = GetLastError();
log() << "MapViewOfFileEx failed " << filename() << " " << errnoWithDescription(e) << endl;
assert(p);
}
assert(p == oldPrivateAddr);
return p;
}
#endif
void MongoMMF::remapThePrivateView() {
assert( cmdLine.dur );
// todo 1.9 : it turns out we require that we always remap to the same address.
// so the remove / add isn't necessary and can be removed
privateViews.remove(_view_private);
_view_private = remapPrivateView(_view_private);
privateViews.add(_view_private, this);
}
/** register view. threadsafe */
void PointerToMMF::add(void *view, MongoMMF *f) {
assert(view);
assert(f);
mutex::scoped_lock lk(_m);
_views.insert( pair<void*,MongoMMF*>(view,f) );
}
/** de-register view. threadsafe */
void PointerToMMF::remove(void *view) {
if( view ) {
mutex::scoped_lock lk(_m);
_views.erase(view);
}
}
PointerToMMF::PointerToMMF() : _m("PointerToMMF") {
#if defined(SIZE_MAX)
size_t max = SIZE_MAX;
#else
size_t max = ~((size_t)0);
#endif
assert( max > (size_t) this ); // just checking that no one redef'd SIZE_MAX and that it is sane
// this way we don't need any boundary checking in _find()
_views.insert( pair<void*,MongoMMF*>((void*)0,(MongoMMF*)0) );
_views.insert( pair<void*,MongoMMF*>((void*)max,(MongoMMF*)0) );
}
/** underscore version of find is for when you are already locked
@param ofs out return our offset in the view
@return the MongoMMF to which this pointer belongs
*/
MongoMMF* PointerToMMF::find_inlock(void *p, /*out*/ size_t& ofs) {
//
// .................memory..........................
// v1 p v2
// [--------------------] [-------]
//
// e.g., _find(p) == v1
//
const pair<void*,MongoMMF*> x = *(--_views.upper_bound(p));
MongoMMF *mmf = x.second;
if( mmf ) {
size_t o = ((char *)p) - ((char*)x.first);
if( o < mmf->length() ) {
ofs = o;
return mmf;
}
}
return 0;
}
/** find associated MMF object for a given pointer.
threadsafe
@param ofs out returns offset into the view of the pointer, if found.
@return the MongoMMF to which this pointer belongs. null if not found.
*/
MongoMMF* PointerToMMF::find(void *p, /*out*/ size_t& ofs) {
mutex::scoped_lock lk(_m);
return find_inlock(p, ofs);
}
PointerToMMF privateViews;
/* void* MongoMMF::switchToPrivateView(void *readonly_ptr) {
assert( cmdLine.dur );
assert( testIntent );
void *p = readonly_ptr;
{
size_t ofs=0;
MongoMMF *mmf = ourReadViews.find(p, ofs);
if( mmf ) {
void *res = ((char *)mmf->_view_private) + ofs;
return res;
}
}
{
size_t ofs=0;
MongoMMF *mmf = privateViews.find(p, ofs);
if( mmf ) {
log() << "dur: perf warning p=" << p << " is already in the writable view of " << mmf->filename() << endl;
return p;
}
}
// did you call writing() with a pointer that isn't into a datafile?
log() << "dur error switchToPrivateView " << p << endl;
return p;
}*/
/* switch to _view_write. normally, this is a bad idea since your changes will not
show up in _view_private if there have been changes there; thus the leading underscore
as a tad of a "warning". but useful when done with some care, such as during
initialization.
*/
void* MongoMMF::_switchToWritableView(void *p) {
size_t ofs;
MongoMMF *f = privateViews.find(p, ofs);
assert( f );
return (((char *)f->_view_write)+ofs);
}
extern string dbpath;
// here so that it is precomputed...
void MongoMMF::setPath(string f) {
string suffix;
string prefix;
bool ok = str::rSplitOn(f, '.', prefix, suffix);
uassert(13520, str::stream() << "MongoMMF only supports filenames in a certain format " << f, ok);
if( suffix == "ns" )
_fileSuffixNo = dur::JEntry::DotNsSuffix;
else
_fileSuffixNo = (int) str::toUnsigned(suffix);
_p = RelativePath::fromFullPath(prefix);
}
bool MongoMMF::open(string fname, bool sequentialHint) {
setPath(fname);
_view_write = mapWithOptions(fname.c_str(), sequentialHint ? SEQUENTIAL : 0);
return finishOpening();
}
bool MongoMMF::create(string fname, unsigned long long& len, bool sequentialHint) {
setPath(fname);
_view_write = map(fname.c_str(), len, sequentialHint ? SEQUENTIAL : 0);
return finishOpening();
}
bool MongoMMF::finishOpening() {
if( _view_write ) {
if( cmdLine.dur ) {
_view_private = createPrivateMap();
if( _view_private == 0 ) {
massert( 13636 , "createPrivateMap failed (look in log for error)" , false );
}
privateViews.add(_view_private, this); // note that testIntent builds use this, even though it points to view_write then...
}
else {
_view_private = _view_write;
}
return true;
}
return false;
}
MongoMMF::MongoMMF() : _willNeedRemap(false) {
_view_write = _view_private = 0;
}
MongoMMF::~MongoMMF() {
close();
}
namespace dur {
void closingFileNotification();
}
/*virtual*/ void MongoMMF::close() {
{
if( cmdLine.dur && _view_write/*actually was opened*/ ) {
if( debug )
log() << "closingFileNotication:" << filename() << endl;
dur::closingFileNotification();
}
privateViews.remove(_view_private);
}
_view_write = _view_private = 0;
MemoryMappedFile::close();
}
}
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