Re: [PATCH] increment nr_tasks in io_context when CLONE_IO is set

[Nikanth Karthikesan <knikanth@suse.de>]

On Tue, 2008-04-15 at 09:24 +0200, Jens Axboe wrote:
> On Tue, Apr 15 2008, Nikanth Karthikesan wrote:
> > Increment the nr_tasks associated with the io_context when CLONE_IO flag
> > is set.
> > 
> > Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
> > 
> > --
> > diff --git a/kernel/fork.c b/kernel/fork.c
> > index dd249c3..01e843b 100644
> > --- a/kernel/fork.c
> > +++ b/kernel/fork.c
> > @@ -812,6 +812,7 @@ static int copy_io(unsigned long clone_f
> >  		tsk->io_context = ioc_task_link(ioc);
> >  		if (unlikely(!tsk->io_context))
> >  			return -ENOMEM;
> > +		atomic_inc(&tsk->io_context->nr_tasks);
> >  	} else if (ioprio_valid(ioc->ioprio)) {
> >  		tsk->io_context = alloc_io_context(GFP_KERNEL, -1);
> >  		if (unlikely(!tsk->io_context))
> 
> Fix is correct, however it would be more appropriate in ioc_task_link()
> instead.

Yes. Thanks.

> 
> diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
> index cac4b36..2b7a118 100644
> --- a/include/linux/iocontext.h
> +++ b/include/linux/iocontext.h
> @@ -91,8 +91,10 @@ static inline struct io_context *ioc_task_link(struct io_context *ioc)
>  	 * if ref count is zero, don't allow sharing (ioc is going away, it's
>  	 * a race).
>  	 */
> -	if (ioc && atomic_inc_not_zero(&ioc->refcount))
> +	if (ioc && atomic_inc_not_zero(&ioc->refcount)) {
> +		atomic_inc(&ioc->nr_tasks);
>  		return ioc;
> +	}
>  
>  	return NULL;
>  }
>