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List:       helix-server-cvs
Subject:    [Server-cvs] engine/core/pub shmem_debug.h,1.1.2.1,1.1.2.2
From:       dcollins () helixcommunity ! org
Date:       2013-08-30 22:52:45
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Update of /cvsroot/server/engine/core/pub
In directory cvs01.internal.helixcommunity.org:/tmp/cvs-serv24325/pub

Modified Files:
      Tag: SERVER_NUCLEUS
	shmem_debug.h 
Log Message:
Synopsis
========
Fixes RPDS memory corruption, possibly related to RPD-1975

Branches:  Jupiter / SERVER_NUCLEUS
Reviewer:  Jamie


Description
===========
Memory allocations and deletions from threads not managed by the server
core (such as httpfsysshim.dll worker threads) were updating the
bytes_in_use_counters[] array using an index of -1, resulting in
updates to the wrong location in memory.

While I detected this when debugging RPD-1975, it may or may not be
related.  I didn't actually trap errors or crashes directly caused by
this, I noticed it while walking through code with the debugger.

The memory in use counter is distributed across multiple integers so
each thread can update a counter without colliding with other threads.
For non-server-core threads, we now update the last item in the counter
array, MAX_THREADS-1.

I also noticed an old bug in that the bytes_in_use_counters array was
not being initialized correctly, which could lead to an unreliable
memory usage counter.  This is fixed as well in this diff.


Files Affected
==============
server/engine/core/memsys.cpp
server/engine/core/pub/memsys.h
server/engine/core/shmem_debug.cpp
server/engine/core/pub/shmem_debug.h


Testing Performed
=================
Unit Tests:
- None

Integration Tests:
- Performed cloud uploads using the Virtual Folder.
- Tested with debug memory and the default system-based memory.

Leak Tests:
- None

Performance Tests:
- None

Platforms Tested:  Windows 7 / x86 (Debug & Release)
Builds Verified:  VC10 / x86 / Debug & Release


QA Hints
========
N/A 



Index: shmem_debug.h
===================================================================
RCS file: /cvsroot/server/engine/core/pub/shmem_debug.h,v
retrieving revision 1.1.2.1
retrieving revision 1.1.2.2
diff -u -d -r1.1.2.1 -r1.1.2.2
--- shmem_debug.h	24 Jul 2012 01:25:23 -0000	1.1.2.1
+++ shmem_debug.h	30 Aug 2013 22:52:27 -0000	1.1.2.2
@@ -247,6 +247,27 @@
     return g_pSizeToBucket[size >> 4];
 }
 
+inline void
+update_bytes_in_use_counter(HX_SIZE_T* pCounters, int nDelta)
+{
+    int nProcnumForCounter = Process::get_procnum();
+    if (nProcnumForCounter >= 0)
+    {
+        // counter for server-core-based threads
+        pCounters[nProcnumForCounter] += nDelta;
+    }
+    else
+    {
+        // Unmanaged threads don't have a procnum.  Since there may be multiple
+        // of these threads, we use an atomic operator.
+        nProcnumForCounter = MAX_THREADS-1;
+#if defined(_WIN64) || defined(_LONG_IS_64)
+        HXAtomicAddINT64((INT64*)&(pCounters[nProcnumForCounter]), nDelta);
+#else
+        HXAtomicAddINT32((INT32*)&(pCounters[nProcnumForCounter]), nDelta);
+#endif
+    }
+}
 
 class _InUsePage;
 
@@ -452,6 +473,7 @@
         {
             nSum += self->bytes_in_use_counters[i];
         }
+        nSum += self->bytes_in_use_counters[MAX_THREADS-1];
         *self->bytes_in_use = nSum;
         return nSum;
     }


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