linux-kernel - Re: [RFC][PATCH] slub: Check for page NULL before doing the node

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Message-ID: <1358447864.23211.34.camel@gandalf.local.home>
Date:	Thu, 17 Jan 2013 13:37:44 -0500
From:	Steven Rostedt <rostedt@...dmis.org>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	linux-mm <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Christoph Lameter <cl@...ux-foundation.org>,
	Pekka Enberg <penberg@...nel.org>,
	Matt Mackall <mpm@...enic.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	RT <linux-rt-users@...r.kernel.org>,
	Clark Williams <clark@...hat.com>,
	John Kacur <jkacur@...il.com>,
	"Luis Claudio R. Goncalves" <lgoncalv@...hat.com>
Subject: Re: [RFC][PATCH] slub: Check for page NULL before doing the
 node_match check

On Thu, 2013-01-17 at 13:10 -0500, Steven Rostedt wrote:

> diff --git a/mm/slub.c b/mm/slub.c
> index 2d9511a..85b95d5 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2399,7 +2399,7 @@ redo:
>  
>  	object = c->freelist;
>  	page = c->page;
> -	if (unlikely(!object || !node_match(page, node)))
> +	if (unlikely(!object || !page || !node_match(page, node)))

I'm still trying to see if c->freelist != NULL and c->page == NULL isn't
a bug. The cmpxchg_doubles are a little confusing. If it's not expected
that page is NULL but freelist isn't than we need to figure out why it
happened.

-- Steve

>  		object = __slab_alloc(s, gfpflags, node, addr, c);
>  
>  	else {
> 
> 


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