Subject: Re: MAP_ANON
To: =?iso-8859-1?Q?Erik_=C4ngg=E5rd?= <>
From: David Laight <>
List: tech-kern
Date: 03/18/2003 12:15:51
On Tue, Mar 18, 2003 at 12:59:40PM +0100, Erik Änggård wrote:
> Martin Husemann wrote:
> >"The file descriptor used for creating MAP_ANON regions is used only for 
> >naming" - what does that mean?
> >  
> >
> If you want two processes to share a chunk of memory (hence it has to be 
> named) but you don't want that memory to be backed by a file 
> (unnecessary disk i/o). That is how I interpreted it.

Nope, you just have to make one process be a child of the other.

I can't see how an open fd helps to 'name' anything.  Nothing actually
knows the name used to open the fd anyway.

SYSV named shared memory segments have entirly different semantics.
(and are really good at consuming kernel memory.swap).


David Laight: