/*
* Extraction d'une page du cache
* Cache page extraction
*/
Page* getNextPage()
{
CacheEntry *entry = NULL;
unsigned long nr=0;
bool notUnregister = false;
Page *page;
// Get the next page number
switch (_policy) {
case EveryPagesIncreasing:
nr = _lastPageRequested + 1;
break;
case EvenDecreasing:
if (_lastPageRequested > 2)
nr = _lastPageRequested - 2;
else {
nr = 1;
setCachePolicy(OddIncreasing);
}
break;
case OddIncreasing:
if (!_lastPageRequested)
nr = 1;
else
nr = _lastPageRequested + 2;
break;
}
DEBUGMSG(_("Next requested page : %lu (# pages into memory=%lu/%u)"), nr,
_pagesInMemory, CACHESIZE);
// Wait for the page
while (nr && (!_numberOfPages || _numberOfPages >= nr)) {
{
_pageTableLock.lock();
if (_maxPagesInTable >= nr && _pages[nr - 1] &&
!_pages[nr - 1]->isSwapped()) {
entry = _pages[nr - 1];
_pages[nr - 1] = NULL;
if (!entry->previous() && !entry->next() && entry != _inMemory)
notUnregister = true;
if (entry->previous())
entry->previous()->setNext(entry->next());
if (entry->next())
entry->next()->setPrevious(entry->previous());
if (entry == _inMemory)
_inMemory = entry->next();
if (entry == _inMemoryLast)
_inMemoryLast = NULL;
_pageTableLock.unlock();
break;
} else if (_maxPagesInTable >= nr && _pages[nr - 1] &&
_pages[nr - 1]->isSwapped())
_work++;
_pageRequested = nr;
_pageTableLock.unlock();
}
_pageAvailable--;
};
// Extract the page instance
if (!entry)
return NULL;
_pagesInTable--;
_lastPageRequested = nr;
page = entry->page();
delete entry;
// Preload a new page
if (!notUnregister)
_pagesInMemory--;
_work++;
return page;
}
static void* _cacheControllerThread(void *_exitVar)
{
bool *needToExit = (bool *)_exitVar;
bool whatToDo = true;
DEBUGMSG(_("Cache controller thread loaded and is waiting for a job"));
while (!(*needToExit)) {
bool preloadPage = false;
// Waiting for a job
_work--;
#ifdef DUMP_CACHE
if (_pagesInMemory) {
CacheEntry *tmp = _inMemory;
fprintf(stderr, _("DEBUG: [34mCache dump: "));
for (unsigned int i=0; i < _pagesInMemory && tmp; i++) {
fprintf(stderr, "%lu ", tmp->page()->pageNr());
tmp = tmp->next();
}
fprintf(stderr, "[0m\n");
} else
fprintf(stderr, _("DEBUG: [34mCache empty[0m\n"));
#endif /* DUMP_CACHE */
// Does the thread needs to exit?
if (*needToExit)
break;
/*
* Check what action to do
*/
// Nothing?
if (!_waitingList && (_pagesInMemory == CACHESIZE ||
_pagesInMemory == _pagesInTable))
continue;
// new page to append and pages to preload?
// Choose one action of them to do (and inverse the action to do at
// each loop)
if (_waitingList && !(_pagesInMemory == CACHESIZE ||
_pagesInMemory == _pagesInTable)) {
preloadPage = whatToDo;
whatToDo = ~whatToDo;
// One of the two thing to do
} else
preloadPage = (_waitingList == NULL);
/*
* Preload a page
*/
if (preloadPage) {
__manageMemoryCache(NULL);
/*
* Store a page
*/
} else {
CacheEntry *entry;
// Get the cache entry to store
{
_waitingListLock.lock();
entry = _waitingList;
_waitingList = entry->next();
if (_lastWaitingList == entry)
_lastWaitingList = NULL;
_waitingListLock.unlock();
}
// Store the entry in the page table
{
_pageTableLock.lock();
// Resize the page table if needed
while (entry->page()->pageNr() > _maxPagesInTable) {
if (!_maxPagesInTable) {
_maxPagesInTable = CACHESIZE;
_pages = new CacheEntry*[_maxPagesInTable];
memset(_pages, 0, _maxPagesInTable *
sizeof(CacheEntry*));
} else {
CacheEntry** tmp = new CacheEntry*[_maxPagesInTable*10];
memcpy(tmp, _pages, _maxPagesInTable *
sizeof(CacheEntry*));
memset(tmp + _maxPagesInTable, 0, _maxPagesInTable * 9 *
sizeof(CacheEntry*));
delete[] _pages;
_pages = tmp;
_maxPagesInTable *= 10;
}
}
// Store the page in the table
_pages[entry->page()->pageNr() - 1] = entry;
_pageTableLock.unlock();
}
_pagesInTable++;
// Does the main thread needs this page?
if (_pageRequested == entry->page()->pageNr()) {
_pageTableLock.lock();
entry->setNext(NULL);
entry->setPrevious(NULL);
_pageAvailable++;
_pageTableLock.unlock();
// So check whether the page can be kept in memory or have to
// be swapped on the disk
} else
__manageMemoryCache(entry);
}
}
DEBUGMSG(_("Cache controller unloaded. See ya"));
return NULL;
}
