Re: [PATCH 2.6.9] fork: add a hook in do_fork()

[Christoph Hellwig <hch@infradead.org>]

On Tue, Nov 23, 2004 at 07:03:17AM +0100, Guillaume Thouvenin wrote:
> Hello,
> 
>    For a module, I need to execute a function when a fork occurs. My
> solution is to add a pointer to a function (called fork_hook) in the
> do_fork() and if this pointer isn't NULL, I call the function. To update
> the pointer to the function I export a symbol (called trace_fork) that
> defines another function with two parameters (the hook and an
> identifier). This function provides a simple mechanism to manage access
> to the fork_hook variable.
> 
>    I don't know if this solution is good but it's easy to implement and
> it just does the trick. I made some tests and it doesn't impact the
> performance of the Linux kernel. 
> 
>    I'd like to have your comment about this patch. Is it useful and is
> it needed by someone else than me? 

Use SGI's PAGG patches if you want such hooks.  Also this is clearly
a _GPL export.