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Date: Fri, 20 Jan 2006 14:18:01 -0800
From: Andrew Morton <akpm@osdl.org>
To: Ingo Oeser <ioe-lkml@rameria.de>
Cc: linux-kernel@vger.kernel.org, dsingleton@mvista.com, drepper@gmail.com,
       mingo@elte.hu
Subject: Re: [robust-futex-4] futex: robust futex support
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Ingo Oeser <ioe-lkml@rameria.de> wrote:
>
> > > +	list_for_each_entry_safe(this, next, head, list) {
> > > +		list_del(&this->list);
> > > +		kmem_cache_free(robust_futex_cachep, this);
> > > +	}
> > 
> > If we're throwing away the entire contents of the list, there's no need to
> > detach items as we go.
>  
> Couldn't even detach the list elements first by
> 
> list_splice_init(&mapping->robust_head->robust_list, head);
> 
> and free the list from "head" after releasing the mutex? 
> This would reduce lock contention, no?

Yes, it would reduce lock contention nicely.