Re: [Boost-bugs] [Boost C++ Libraries] #9019: Bug: mapped_region shouldn't create a new file mapping but reuse the one provided in file_mapping

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #9019: Bug: mapped_region shouldn't create a new file mapping but reuse the one provided in file_mapping
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2013-08-20 17:30:38

#9019: Bug: mapped_region shouldn't create a new file mapping but reuse the one
provided in file_mapping
-------------------------+-------------------------------------------------
  Reporter:              |      Owner:  igaztanaga
  michal.fronczyk@…      |     Status:  new
      Type:  Bugs        |  Component:  interprocess
 Milestone:  To Be       |   Severity:  Optimization
  Determined             |   Keywords:  interprocess mapped_region
   Version:  Boost       |  file_mapping
  1.54.0                 |
Resolution:              |
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Comment (by igaztanaga):

 Calling CreateFileMapping in the file_mapping class is not a trivial task
 as the size of the file can change and the file mapping would need to be
 recreated on the fly. Also, it wouldn't allow the same  file using copy on
 write as the file mapping must be opened with an special flag for that
 purpose, whereas another view would like to write directly to the file. Do
 you have any performance numbers about the overhead of not reusing the
 file mapping? All portable shared memory interfaces I know create new file
 mappings when mapping the memory so I guess the performance impact is not
 very high.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/9019#comment:1>
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