Date: Mon, 15 Feb 2010 21:22:21 +1100
From: Nick Piggin <npiggin@suse.de>
To: Andi Kleen <andi@firstfloor.org>
Cc: penberg@cs.helsinki.fi, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
       haicheng.li@intel.com, rientjes@google.com
Subject: Re: [PATCH] [1/4] SLAB: Handle node-not-up case in
 fallback_alloc() v2
Message-ID: <20100215102221.GL5723@laptop>
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 <20100211205401.002CFB1978@basil.firstfloor.org>
 <20100215060400.GG5723@laptop>
 <20100215100712.GC21783@one.firstfloor.org>
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On Mon, Feb 15, 2010 at 11:07:12AM +0100, Andi Kleen wrote:
> > This is a better way to go anyway because it really is a proper
> > "fallback" alloc. I think that possibly used to work (ie. kmem_getpages
> > would be able to pass -1 for the node there) but got broken along the
> > line.
> 
> Thanks for the review.
> 
> I should add there's still one open problem: in some cases 
> the oom killer kicks in on hotadd. Still working on that one.
> 
> In general hotadd was mighty bitrotted :/

Yes, that doesn't surprise me. I'm sure you can handle it, but send
some traces if you have problems.

 
> > Although it's not such a hot path to begin with, care to put a branch
> > annotation there?
> 
> pointer == NULL is already default unlikely in gcc
> 
> /* Pointers are usually not NULL.  */
> DEF_PREDICTOR (PRED_POINTER, "pointer", HITRATE (85), 0)
> DEF_PREDICTOR (PRED_TREE_POINTER, "pointer (on trees)", HITRATE (85), 0)

Well I still prefer to annotate it. I think builtin expect is 99%.

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