Re: [PATCH] mm: cleanup and document reclaim recursion

[Andrew Morton <akpm@osdl.org>]

On Thu, 16 Nov 2006 10:52:25 +0100
Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:

> On Wed, 2006-11-15 at 14:00 -0800, Andrew Morton wrote:
> > On Wed, 15 Nov 2006 22:32:58 +0100
> > Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> > 
> > > +			current->flags |= PF_MEMALLOC;
> > >  			try_to_free_pages(zones, GFP_NOFS);
> > > +			current->flags &= ~PF_MEMALLOC;
> > 
> > Sometime, later, in a different patch, we might as well suck that into
> > try_to_free_pages() itself.   Along with nice comment explaining
> > what it means and WARN_ON(current->flags & PF_MEMALLOC).
> 
> ---
> 
> Cleanup and document the reclaim recursion avoiding properties of PF_MEMALLOC.
> 
> ..

hmm.

>  
> +	/* We're already in reclaim */
> +	if (current->flags & PF_MEMALLOC)
> +		return;
> +

We're kinda dead if free_more_memory() does this.  It'll go into an
infinite loop.

Recurring back into try_to_free_pages() would actually be a better thing to
do..

Taking a nap might make some sense, not sure.

It all needs more thought, no?

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