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From: David Miller <davem@davemloft.net>
To: laijs@cn.fujitsu.com
Cc: mingo@elte.hu, paulmck@linux.vnet.ibm.com,
	cl@linux-foundation.org, penberg@kernel.org,
	eric.dumazet@gmail.com, mpm@selenic.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 4/4] net,rcu: don't assume the size of struct rcu_head
Date: Tue, 01 Mar 2011 00:16:38 -0800 (PST)	[thread overview]
Message-ID: <20110301.001638.104075130.davem@davemloft.net> (raw)
In-Reply-To: <4D6CA860.3020409@cn.fujitsu.com>

From: Lai Jiangshan <laijs@cn.fujitsu.com>
Date: Tue, 01 Mar 2011 16:03:44 +0800

> 
> struct dst_entry assumes the size of struct rcu_head as 2 * sizeof(long)
> and manually adds pads for aligning for "__refcnt".
> 
> When the size of struct rcu_head is changed, these manual padding
> is wrong. Use __attribute__((aligned (64))) instead.
> 
> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>

We don't want to use the align if it's going to waste lots of space.

Instead we want to rearrange the structure so that the alignment comes
more cheaply.

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  reply	other threads:[~2011-03-01  8:16 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-01  8:03 [PATCH 4/4] net,rcu: don't assume the size of struct rcu_head Lai Jiangshan
2011-03-01  8:16 ` David Miller [this message]
2011-03-01  8:20   ` Eric Dumazet
2011-03-01  8:53   ` [PATCH 4/4 V2] " Lai Jiangshan
2011-03-01  9:20     ` Eric Dumazet
2011-03-02  2:46       ` Lai Jiangshan
2011-03-02  3:02         ` Eric Dumazet
2011-03-01  8:20 ` [PATCH 4/4] " Eric Dumazet

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