[mod_python] global persistence

Sterling Hughes sterling at bumblebury.com
Wed Jun 25 01:16:51 EST 2003


The way you handle locking with mmap() is by using a combination of a
file and a mmap(), it isn't that expensive so long as MAP_NOSYNC is
specified (if MAP_NOSYNC isn't specified than most operating systems
default to it).  

Outside of that, the proper way to do this is to use a semaphore.

-Sterling

On Wed, 2003-06-25 at 00:40, Gregory (Grisha) Trubetskoy wrote:
> On Tue, 24 Jun 2003 mod_python at mikebell.org wrote:
> 
> > On Wed, Jun 25, 2003 at 12:16:29AM -0400, Gregory (Grisha) Trubetskoy wrote:
> > > http://www.python.org/doc/current/lib/module-mmap.html
> >
> > The only problem with the mmap module is that it just gives you a
> > string-like object. How do you put something like a mutex in there so
> > you can access the shared memory area safely?
> >
> 
> To quote Guido - "Good question!"
> 
> (here is the link
> http://mail.python.org/pipermail/python-dev/2001-August/016772.html)
> 
> :-)
> 
> OK, on a serious note - I believe the shm module provides locking. I'm
> also going to look into the APR for possibly including some locking
> interface in the next version of mp.
> 
> Grisha
> 
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