netdev - RE: [PATCH 06/26] netfilter: conntrack: align nf

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Message-ID: <063D6719AE5E284EB5DD2968C1650D6D5F4F18C1@AcuExch.aculab.com>
Date:	Wed, 6 Jul 2016 14:45:29 +0000
From:	David Laight <David.Laight@...LAB.COM>
To:	'Pablo Neira Ayuso' <pablo@...filter.org>,
	"netfilter-devel@...r.kernel.org" <netfilter-devel@...r.kernel.org>
CC:	"davem@...emloft.net" <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH 06/26] netfilter: conntrack: align nf_conn on cacheline
 boundary

From: Pablo Neira Ayuso
> Sent: 06 July 2016 15:24
> From: Florian Westphal <fw@...len.de>
> 
> increases struct size by 32 bytes (288 -> 320), but it is the right thing,
> else any attempt to (re-)arrange nf_conn members by cacheline won't work.
...
>  	nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
>  						sizeof(struct nf_conn), 0,
> -						SLAB_DESTROY_BY_RCU, NULL);
> +						SLAB_DESTROY_BY_RCU | SLAB_HWCACHE_ALIGN, NULL);

What happens on systems with cache lines that are longer than 64 bytes?
(I'm pretty sure some ppc systems have long cache lines.)

	David