XrdFileCache.cc

//----------------------------------------------------------------------------------
// Copyright (c) 2014 by Board of Trustees of the Leland Stanford, Jr., University
// Author: Alja Mrak-Tadel, Matevz Tadel, Brian Bockelman
//----------------------------------------------------------------------------------
// XRootD is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// XRootD 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 General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with XRootD.  If not, see <http://www.gnu.org/licenses/>.
//----------------------------------------------------------------------------------

#include <fcntl.h>
#include <sstream>
#include <algorithm>
#include <sys/statvfs.h>

#include "XrdCl/XrdClConstants.hh"
#include "XrdCl/XrdClURL.hh"
#include "XrdSys/XrdSysPthread.hh"
#include "XrdSys/XrdSysTimer.hh"
#include "XrdOss/XrdOss.hh"
#include "XrdOuc/XrdOucEnv.hh"
#include "XrdOuc/XrdOucUtils.hh"
#include "XrdOuc/XrdOucTrace.hh"

#include "XrdFileCache.hh"
#include "XrdFileCacheTrace.hh"
#include "XrdFileCacheInfo.hh"
#include "XrdFileCacheIOEntireFile.hh"
#include "XrdFileCacheIOFileBlock.hh"

using namespace XrdFileCache;

Cache * Cache::m_factory = NULL;


void *CacheDirCleanupThread(void* cache_void)
{
   Cache::GetInstance().CacheDirCleanup();
   return NULL;
}

void *ProcessWriteTaskThread(void* c)
{
   Cache *cache = static_cast<Cache*>(c);
   cache->ProcessWriteTasks();
   return NULL;
}

void *PrefetchThread(void* ptr)
{
   Cache* cache = static_cast<Cache*>(ptr);
   cache->Prefetch();
   return NULL;
}


extern "C"
{
XrdOucCache2 *XrdOucGetCache2(XrdSysLogger *logger,
                            const char   *config_filename,
                            const char   *parameters)
{
   XrdSysError err(0, "");
   err.logger(logger);
   err.Emsg("Retrieve", "Retrieving a caching proxy factory.");
   Cache &factory = Cache::GetInstance();
   if (!factory.Config(logger, config_filename, parameters))
   {
      err.Emsg("Retrieve", "Error - unable to create a factory.");
      return NULL;
   }
   err.Emsg("Retrieve", "Success - returning a factory.");

   pthread_t tid1;
   XrdSysThread::Run(&tid1, ProcessWriteTaskThread, (void*)(&factory), 0, "XrdFileCache WriteTasks ");

   pthread_t tid2;
   XrdSysThread::Run(&tid2, PrefetchThread, (void*)(&factory), 0, "XrdFileCache Prefetch ");


   pthread_t tid;
   XrdSysThread::Run(&tid, CacheDirCleanupThread, NULL, 0, "XrdFileCache CacheDirCleanup");
   return &factory;
}
}

Cache &Cache::GetInstance()
{
   if (m_factory == NULL)
      m_factory = new Cache();
   return *m_factory;
}

// !AMT will be obsolete in future
XrdOucCache *Cache::Create(Parms & parms, XrdOucCacheIO::aprParms * prParms)
{
   return this;
}


//______________________________________________________________________________

bool Cache::Decide(XrdOucCacheIO* io)
{
   if (!m_decisionpoints.empty())
   {
      std::string filename = io->Path();
      std::vector<Decision*>::const_iterator it;
      for (it = m_decisionpoints.begin(); it != m_decisionpoints.end(); ++it)
      {
         XrdFileCache::Decision *d = *it;
         if (!d) continue;
         if (!d->Decide(filename, *m_output_fs))
         {
            return false;
         }
      }
   }

   return true;
}
//______________________________________________________________________________


Cache::Cache() : XrdOucCache(),
     m_log(0, "XrdFileCache_"),
     m_trace(0),
     m_traceID("Manager"),
     m_prefetch_condVar(0),
     m_RAMblocks_used(0)
{
    m_trace = new XrdOucTrace(&m_log);
    // default log level is Warning
    m_trace->What = 2;
}

//______________________________________________________________________________

XrdOucCacheIO2 *Cache::Attach(XrdOucCacheIO2 *io, int Options)
{
   if (Cache::GetInstance().Decide(io))
   {
      TRACE(Debug, "Cache::Attach() " << io->Path());
      IO* cio;
      if (Cache::GetInstance().RefConfiguration().m_hdfsmode)
         cio = new IOFileBlock(io, m_stats, *this);
      else
         cio = new IOEntireFile(io, m_stats, *this);

      TRACE_PC(Info, const char* loc = io->Location(),
               "Cache::Attach() " << io->Path() << " location: " <<
               ((loc && loc[0] != 0) ? loc : "<deferred open>"));
      return cio;
   }
   else
   {
       TRACE(Info, "Cache::Attach() decision decline " << io->Path());
   }
   return io;
}
//______________________________________________________________________________


int Cache::isAttached()
{
    // virutal function of XrdOucCache, don't see it used in pfc or posix layer
    return true;
}

void Cache::Detach(XrdOucCacheIO* io)
{
   TRACE(Info, "Cache::Detach() " << io->Path());

   // Cache owns File objects
   XrdSysMutexHelper lock(&m_active_mutex);
   std::vector<DiskNetIO>::iterator it = m_active.begin();
   while ( it != m_active.end() )
   {
      if (it->io == io) {
         if (it->file) {
            it->io->RelinquishFile(it->file);
            delete it->file;
         }
         m_active.erase(it);
         if (m_configuration.m_hdfsmode == false) break;
      }
      else
         ++it;
   }

   delete io;
}

//______________________________________________________________________________
void
Cache::AddWriteTask(Block* b, bool fromRead)
{
   TRACE(Dump, "Cache::AddWriteTask() bOff=%ld " <<  b->m_offset);
   m_writeQ.condVar.Lock();
   if (fromRead)
       m_writeQ.queue.push_back(b);
   else
      m_writeQ.queue.push_front(b); // AMT should this not be the opposite
   m_writeQ.size++;
   m_writeQ.condVar.Signal();
   m_writeQ.condVar.UnLock();
}

//______________________________________________________________________________
void Cache::RemoveWriteQEntriesFor(File *iFile)
{
   m_writeQ.condVar.Lock();
   std::list<Block*>::iterator i = m_writeQ.queue.begin();
   while (i != m_writeQ.queue.end())
   {
      if ((*i)->m_file == iFile)
      {
         TRACE(Dump, "Cache::Remove entries for " <<  (void*)(*i) << " path " <<  iFile->lPath());
         std::list<Block*>::iterator j = i++;
         iFile->BlockRemovedFromWriteQ(*j);
         m_writeQ.queue.erase(j);
         --m_writeQ.size;
      }
      else
      {
         ++i;
      }
   }
   m_writeQ.condVar.UnLock();
}

//______________________________________________________________________________
void
Cache::ProcessWriteTasks()
{
   while (true)
   {
      m_writeQ.condVar.Lock();
      while (m_writeQ.queue.empty())
      {
         m_writeQ.condVar.Wait();
      }
      Block* block = m_writeQ.queue.front(); // AMT should not be back ???
      m_writeQ.queue.pop_front();
      m_writeQ.size--;
      TRACE(Dump, "Cache::ProcessWriteTasks  for %p " <<  (void*)(block) << " path " << block->m_file->lPath());
      m_writeQ.condVar.UnLock();

      block->m_file->WriteBlockToDisk(block);
   }
}

//______________________________________________________________________________

bool
Cache::RequestRAMBlock()
{
   XrdSysMutexHelper lock(&m_RAMblock_mutex);
   if ( m_RAMblocks_used < Cache::GetInstance().RefConfiguration().m_NRamBuffers )
   {
      m_RAMblocks_used++;
      return true;
   }
   return false;
}

void
Cache::RAMBlockReleased()
{
   XrdSysMutexHelper lock(&m_RAMblock_mutex);
   m_RAMblocks_used--;
}

void
Cache::AddActive(IO* io, File* file)
{
   XrdSysMutexHelper lock(&m_active_mutex);
   m_active.push_back(DiskNetIO(io, file));
}

//==============================================================================
//======================= File relinquish at process of dying  ===================
//======================================================================
File* Cache::GetFileWithLocalPath(std::string path, IO* iIo)
{
   XrdSysMutexHelper lock(&m_active_mutex);
   for ( std::vector<DiskNetIO>::iterator it = m_active.begin(); it != m_active.end(); ++it)
   {
      if (it->file && (!strcmp(path.c_str(), it->file->lPath())))
      {
         File *ff = it->file;
         it->io->RelinquishFile(ff);
         it->file = 0;
         return  ff;
      }
   }
   return 0;
}

//==============================================================================
//=======================  PREFETCH ===================================
//==============================================================================
/*
namespace {
struct prefetch_less_than
{
    inline bool operator() (const File* struct1, const File* struct2)
    {
        return (struct1->GetPrefetchScore() < struct2->GetPrefetchScore());
    }
}myobject;
}*/
//______________________________________________________________________________

void
Cache::RegisterPrefetchFile(File* file)
{
    //  called from File::Open()

   if (Cache::GetInstance().RefConfiguration().m_prefetch_max_blocks)
   {
      m_prefetch_condVar.Lock();
      m_prefetchList.push_back(file);
      m_prefetch_condVar.Signal();
      m_prefetch_condVar.UnLock();
   }
}

//______________________________________________________________________________

void
Cache::DeRegisterPrefetchFile(File* file)
{
   //  called from last line File::InitiateClose()

   m_prefetch_condVar.Lock();
   for (PrefetchList::iterator it = m_prefetchList.begin(); it != m_prefetchList.end(); ++it) {
      if (*it == file) {
         m_prefetchList.erase(it);
         break;
      }
   }
   m_prefetch_condVar.UnLock();
}

//______________________________________________________________________________

File* 
Cache::GetNextFileToPrefetch()
{
   m_prefetch_condVar.Lock();
   while (m_prefetchList.empty()) {
      m_prefetch_condVar.Wait();
   }

   //  std::sort(m_prefetchList.begin(), m_prefetchList.end(), myobject);

   size_t l = m_prefetchList.size();
   int idx = rand() % l;
   File* f = m_prefetchList[idx];

   m_prefetch_condVar.UnLock();
   return f;
}

//______________________________________________________________________________
//! Preapare the cache for a file open request. This method is called prior to
//! actually opening a file. This method is meant to allow defering an open
//! request or implementing the full I/O stack in the cache layer.
//! @return <0 Error has occurred, return value is -errno; fail open request.
//!         =0 Continue with open() request.
//!         >0 Defer open but treat the file as actually being open. Use the
//!            XrdOucCacheIO2::Open() method to open the file at a later time.
//------------------------------------------------------------------------------

int 
Cache::Prepare(const char *url, int oflags, mode_t mode)
{
   std::string curl(url);
   XrdCl::URL xx(curl);
   std::string spath = xx.GetPath();
   spath += ".cinfo";

   struct stat buf;
   int res = m_output_fs->Stat(spath.c_str(), &buf);
   if (res == 0) {
      TRACE( Dump, "Cache::Prefetch defer open " << spath);
      return 1;
   }
   else {
      return 0;
   }
}

//______________________________________________________________________________
// virtual method of XrdOucCache2::Stat()
//!
//! @return <0 - Stat failed, value is -errno.
//!         =0 - Stat succeeded, sbuff holds stat information.
//!         >0 - Stat could not be done, forward operation to next level.
//------------------------------------------------------------------------------

int Cache::Stat(const char *curl, struct stat &sbuff)
{
   XrdCl::URL url(curl);
   std::string name = url.GetPath();
   name += ".cinfo";

   if (m_output_fs->Stat(name.c_str(), &sbuff) == XrdOssOK) {
      if ( S_ISDIR(sbuff.st_mode)) {
         return 0;
      }
      else {
         bool success = false;
         XrdOssDF* infoFile = m_output_fs->newFile(m_configuration.m_username.c_str()); 
         XrdOucEnv myEnv; 
         int res = infoFile->Open(name.c_str(), O_RDONLY, 0600, myEnv);
         if (res >= 0) {
            Info info(m_trace, 0);
            if (info.Read(infoFile, name))
            {
               sbuff.st_size = info.GetFileSize();
               success = true;
            }
         }
         infoFile->Close();
         delete infoFile;
         return success ? 0 : 1;
      }
   }
   
   return 1;
}

//______________________________________________________________________________


void 
Cache::Prefetch()
{
   int limitRAM= Cache::GetInstance().RefConfiguration().m_NRamBuffers * 0.7;
   while (true) {
      m_RAMblock_mutex.Lock();
      bool doPrefetch = (m_RAMblocks_used < limitRAM);
      m_RAMblock_mutex.UnLock();

      if (doPrefetch) {
         File* f = GetNextFileToPrefetch();
         f->Prefetch();
      }
      else {
         XrdSysTimer::Wait(5);
      }
   }  
}