[Boost-bugs] [Boost C++ Libraries] #4960: boost::pool_allocator for vector of vectors exhausts memory

Subject: [Boost-bugs] [Boost C++ Libraries] #4960: boost::pool_allocator for vector of vectors exhausts memory
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-12-07 23:42:34

#4960: boost::pool_allocator for vector of vectors exhausts memory
-------------------------------------+--------------------------------------
 Reporter:  mattiasg                 |       Owner:  cnewbold
     Type:  Bugs                     |      Status:  new     
Milestone:  To Be Determined         |   Component:  pool    
  Version:  Boost Development Trunk  |    Severity:  Problem 
 Keywords:                           |  
-------------------------------------+--------------------------------------
 glr9940 reported in #386 that using boost::pool_allocator for a vector of
 vectors caused problems. I have now found a slight extension to the
 example glr9940 reported which does not crash, but exhausts memory even
 for a tiny vector of vectors.

 I have used the development trunk code and gcc 4.1.2.

 {{{#!cpp
 #include <boost/pool/pool_alloc.hpp>
 #include <vector>
 #include <iostream>

 typedef std::vector<int, boost::pool_allocator<int> > EventVector;
 typedef std::vector<EventVector> IndexVector;

 int main()
 {
   IndexVector iv;
   int limit = 100;
   for (int i = 0; i < limit; ++i)
     iv.push_back(EventVector());

   std::cout << "it works\n";
   return 0;
 }
 }}}

 I suspect that the critical value for 'limit' depends on the machine. On
 my machine a limit of 20 seems to work fine, a limit of 24 uses a few Gb
 of memory, while a limit of 30 stalls the process, 'top' showing that the
 memory footprint doubles rapidly until memory is exhausted. I've noticed
 for other examples of this issue that when I replace the vector push_back
 loop with a rolled out version just creating a number of pooled vectors,
 it works fine.

 Have I made some noob mistake, or is this a bug?

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4960>
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