VersatileMemoryPage.cpp

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// $HeadURL: https://hpctoolkit.googlecode.com/svn/branches/hpctoolkit-hpcserver/src/tool/hpcserver/VersatileMemoryPage.cpp $
// $Id: VersatileMemoryPage.cpp 4380 2013-10-16 06:34:29Z felipet1326@gmail.com $
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//***************************************************************************
//
// File:
//   $HeadURL: https://hpctoolkit.googlecode.com/svn/branches/hpctoolkit-hpcserver/src/tool/hpcserver/VersatileMemoryPage.cpp $
//
// Purpose:
//   Manages pages of memory that are mapped and unmapped dynamically from the
//   trace file based on the last time they were used.
//
// Description:
//   [The set of functions, macros, etc. defined in the file]
//
//***************************************************************************

#include <stdio.h>
#include <stdlib.h>
#include <cstring>
#include <list>
#include <errno.h>

#include "DebugUtils.hpp"
#include "VersatileMemoryPage.hpp"
#include "LRUList.hpp"

namespace TraceviewerServer
{
        static int MAX_PAGES_TO_ALLOCATE_AT_ONCE = 0;

        VersatileMemoryPage::VersatileMemoryPage(FileOffset _startPoint, int _size, FileDescriptor _file, LRUList<VersatileMemoryPage>* pageManagementList)
        {
                startPoint = _startPoint;
                size = _size;
                mostRecentlyUsed = pageManagementList;
                index = mostRecentlyUsed->addNewUnused(this);
                file = _file;
                isMapped = false;
                if (MAX_PAGES_TO_ALLOCATE_AT_ONCE <1)
                        cerr<<"Set max pages before creating any VersatileMemoryPages"<<endl;
        }

        void VersatileMemoryPage::setMaxPages(int pages)
        {
                MAX_PAGES_TO_ALLOCATE_AT_ONCE = pages;
        }

        VersatileMemoryPage::~VersatileMemoryPage()
        {
                if (isMapped)
                        unmapPage();
        }
        char* VersatileMemoryPage::get()
        {

                if (!isMapped)
                {
                        mapPage();
                }
                mostRecentlyUsed->putOnTop(index);

                return page;
        }

        void VersatileMemoryPage::mapPage()
        {

                DEBUGCOUT(1) << "Mapping page "<< index<< " "<<mostRecentlyUsed->getUsedPageCount() << " / " << MAX_PAGES_TO_ALLOCATE_AT_ONCE << endl;

                if (isMapped)
                {
                        cerr << "Trying to double map!"<<endl;
                        return;
                }
                if (mostRecentlyUsed->getUsedPageCount() >= MAX_PAGES_TO_ALLOCATE_AT_ONCE)
                {

                        VersatileMemoryPage* toRemove = mostRecentlyUsed->getLast();

                        DEBUGCOUT(1)<<"Kicking " << toRemove->index << " out"<<endl;

                        if (toRemove->isMapped != true)
                                cerr << "Least recently used one isn't even mapped?"<<endl;

                        toRemove->unmapPage();
                        mostRecentlyUsed->removeLast();
                }
                page = (char*)mmap(0, size, MAP_PROT, MAP_FLAGS, file, startPoint);
                if (page == MAP_FAILED)
                {
                        cerr << "Mapping returned error " << strerror(errno) << endl;
                        cerr << "off_t size =" << sizeof(off_t) << "mapping size=" << size << " MapProt=" <<MAP_PROT
                                        << " MapFlags=" << MAP_FLAGS << " fd=" << file << " Start point=" << startPoint << endl;
                        fflush(NULL);
                        exit(-1);
                }


                isMapped = true;
                mostRecentlyUsed->reAdd(index);
        }
        void VersatileMemoryPage::unmapPage()
        {
                if (!isMapped)
                {
                        cerr << "Trying to double unmap!"<<endl;
                        return;
                }
                munmap(page, size);

                isMapped = false;

                DEBUGCOUT(1) << "Unmapped a page"<<endl;

        }

} /* namespace TraceviewerServer */