From 60516e3915e5f5854e8c0286252fae49f63060af Mon Sep 17 00:00:00 2001
From: Alja Mrak-Tadel <amraktadel@ucsd.edu>
Date: Thu, 9 Jul 2015 13:18:28 -0700
Subject: [PATCH] Reserver ram resources in prefetching.

---
 src/XrdFileCache/XrdFileCache.cc     | 39 +++++++++++++++-------------
 src/XrdFileCache/XrdFileCacheFile.cc |  7 ++++-
 2 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/src/XrdFileCache/XrdFileCache.cc b/src/XrdFileCache/XrdFileCache.cc
index b2b678240c0..1a3ad8bf9fe 100644
--- a/src/XrdFileCache/XrdFileCache.cc
+++ b/src/XrdFileCache/XrdFileCache.cc
@@ -217,15 +217,8 @@ Cache::RegisterPrefetchFile(File* file)
 
     if (Factory::GetInstance().RefConfiguration().m_prefetch)
     {
-        if (Factory::GetInstance().RefConfiguration().m_hdfsmode) {
             XrdSysMutexHelper lock(&m_prefetch_mutex);
             m_files.push_back(file);
-        }
-        else 
-        {
-            // don't need to lock it becuse it File object is created in constructor of IOEntireFile
-            m_files.push_back(file);
-        }
     }
 }
 //______________________________________________________________________________
@@ -266,18 +259,28 @@ Cache::GetNextFileToPrefetch()
 void 
 Cache::Prefetch()
 {
+   const static int limitRAM= Factory::GetInstance().RefConfiguration().m_NRamBuffers * 0.7;
+
    XrdCl::DefaultEnv::GetLog()->Dump(XrdCl::AppMsg, "Cache::Prefetch thread start");
-  
-   while (true) {
-      File* f = GetNextFileToPrefetch();
-      XrdCl::DefaultEnv::GetLog()->Dump(XrdCl::AppMsg, "Cache::Prefetch got file (%p)", f);
 
-      if (f) {
-         f->Prefetch();
-      }
-      else {
-         // wait for new file, AMT should I wait for the signal instead ???
-         XrdSysTimer::Wait(1);
+    while (true) {
+      bool doPrefetch = false;
+      m_RAMblock_mutex.Lock();
+      if (m_RAMblocks_used < limitRAM)
+         doPrefetch = true;
+      m_RAMblock_mutex.UnLock();
+
+      if (doPrefetch) {
+         File* f = GetNextFileToPrefetch();
+         XrdCl::DefaultEnv::GetLog()->Dump(XrdCl::AppMsg, "Cache::Prefetch got file (%p)", f);
+         if (f) {
+            f->Prefetch();
+            continue;
+         }
       }
-   }
+
+      // wait for new file or more resources, AMT should I wait for the signal instead ???
+      XrdSysTimer::Wait(1);
+
+   }  
 }
diff --git a/src/XrdFileCache/XrdFileCacheFile.cc b/src/XrdFileCache/XrdFileCacheFile.cc
index b2bbd832639..9be06a3f979 100644
--- a/src/XrdFileCache/XrdFileCacheFile.cc
+++ b/src/XrdFileCache/XrdFileCacheFile.cc
@@ -720,6 +720,7 @@ void File::dec_ref_count(Block* b)
     b-> m_refcnt--;
     if ( b->m_refcnt == 0) {
         int i = b->m_offset/BufferSize();
+        delete m_block_map[i];
         size_t ret = m_block_map.erase(i);
         if (ret != 1) {
             clLog()->Error(XrdCl::AppMsg, "File::OnBlockZeroRefCount did not erase %d from map.", i);
@@ -765,7 +766,10 @@ void File::ProcessBlockResponse(Block* b, XrdCl::XRootDStatus *status)
    // case when there is a prefetch that is failed or prefetch that stopped has just been initated
    if (b->m_refcnt == 0) {
       assert(b->m_prefetch);
-       m_block_map.erase((int)(b->m_offset/BufferSize()));
+      cache()->RAMBlockReleased();
+      int bidx = (int)(b->m_offset/BufferSize());
+      delete m_block_map[bidx];
+      m_block_map.erase(bidx);
    }
 
 
@@ -841,6 +845,7 @@ void File::Prefetch()
                BlockMap_i bi = m_block_map.find(f);
                if (bi == m_block_map.end()) {
                   clLog()->Dump(XrdCl::AppMsg, "Prefetch::Prefetch take block %d", f);
+                  cache()->RequestRAMBlock();
                   RequestBlock(f, true);
                   /// inc_ref_count(b); AMT don't increase it, there is no-one to annulate it 0
                   m_prefetchReadCnt++;