From: Tejun Heo <tj@kernel.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel <linux-kernel@vger.kernel.org>,
David Miller <davem@davemloft.net>, Robin Holt <holt@sgi.com>
Subject: Re: [PATCH] module: struct module_ref should contains long fields
Date: Fri, 16 Dec 2011 07:54:08 -0800 [thread overview]
Message-ID: <20111216155408.GA31770@google.com> (raw)
In-Reply-To: <1324012057.2562.23.camel@edumazet-laptop>
Hello, Eric.
On Fri, Dec 16, 2011 at 06:07:37AM +0100, Eric Dumazet wrote:
> +struct module_ref {
> + unsigned long incs;
> + unsigned long decs;
> +} __attribute((aligned(2 * sizeof(unsigned long))));
Why not ____cacheline_aligned? Another thing is that for percpu
memory, packing could be better or at least shouldn't be worse.
Percpu area usages are likely to be local so one major benefit of
cacheline alignment - avoiding cacheline pingpong - goes away. The
constant is called SMP_CACHE_BYTES after all.
Thanks.
--
tejun
next prev parent reply other threads:[~2011-12-16 15:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-16 5:07 [PATCH] module: struct module_ref should contains long fields Eric Dumazet
2011-12-16 15:54 ` Tejun Heo [this message]
2011-12-16 16:01 ` Eric Dumazet
2011-12-16 16:05 ` Tejun Heo
2011-12-16 16:36 ` Eric Dumazet
2011-12-19 5:48 ` Rusty Russell
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