On 1/31/11 1:47 AM, Daniel Wagner wrote: > On Fri, Jan 28, 2011 at 08:13:28PM -0800, Grant Erickson wrote: >> As far as I can see, the stats mapping is not published or shared outside of >> connman. If so, there's no reason to map it SHARED versus PRIVATE. > >> From the mmap man pages: > > MAP_SHARED > > Share this mapping. Updates to the mapping are visible to > other processes that map this file, and are carried through > to the underlying file. The file may not actually be > updated until msync(2) or munmap() is called. > > MAP_PRIVATE > > Create a private copy-on-write mapping. Updates to the > mapping are not visible to other processes mapping the same > file, and are not carried through to the underlying file. > It is unspecified whether changes made to the file after > the mmap() call are visible in the mapped region. > > The reason for picking MAP_SHARED was to be sure the changes in buffer > really hits the file. I read that MAP_PRIVATE does not garantee this. > This is reason I was picking MAP_SHARED together with msync.
Daniel: Thanks for the clarification on the rationale for choosing MAP_SHARED. I'll have to do some digging in to determine why MAP_SHARED fails on the ARM/Linux 2.6.32 kernel. It might be beneficial to add the above comments to the source file for future reference. Best, Grant _______________________________________________ connman mailing list connman@connman.net http://lists.connman.net/listinfo/connman
