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Date: Mon, 10 May 2004 02:46:58 -0700
From: Andrew Morton <akpm@osdl.org>
To: arjanv@redhat.com
Cc: helgehaf@aitel.hist.no, mpm@selenic.com, linux-kernel@vger.kernel.org
Subject: Re: dentry bloat.
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Arjan van de Ven <arjanv@redhat.com> wrote:
>
> On Mon, 2004-05-10 at 10:27, Helge Hafting wrote:
>  > Matt Mackall wrote:
>  > 
>  > >One also wonders about whether all the RCU stuff is needed on UP. I'm
>  > >not sure if I grok all the finepoints here, but it looks like the
>  > >answer is no and that we can make struct_rcu head empty and have
>  > >call_rcu fall directly through to the callback. This would save
>  > >something like 16-32 bytes (32/64bit), not to mention a bunch of
>  > >dinking around with lists and whatnot.
>  > >
>  > >So what am I missing?
>  > >  
>  > >
>  > Preempt can happen anytime, I believe.
> 
>  ok so for UP-non-preempt we can still get those 16 bytes back from the
>  dentry....

I suppose so.  And on small SMP, really.  We chose not to play those games
early on so the code got the best testing coverage.