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From: Peter Zijlstra <peterz@infradead.org>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Huang, Ying" <ying.huang@intel.com>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Borislav Petkov <bp@suse.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Juergen Gross <jgross@suse.com>, Aaron Lu <aaron.lu@intel.com>
Subject: Re: [PATCH 3/3] IPI: Avoid to use 2 cache lines for one call_single_data
Date: Wed, 2 Aug 2017 12:53:21 +0200	[thread overview]
Message-ID: <20170802105321.3dettvyq4vmcvfth@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1501669138.25002.20.camel@edumazet-glaptop3.roam.corp.google.com>

On Wed, Aug 02, 2017 at 03:18:58AM -0700, Eric Dumazet wrote:
> What we can do instead is to force an alignment on 4*sizeof(void *).
> (32 bytes on 64bit, 16 bytes on 32bit arches)
> 
> Maybe something like this :
> 
> diff --git a/include/linux/smp.h b/include/linux/smp.h
> index 68123c1fe54918c051292eb5ba3427df09f31c2f..f7072bf173c5456e38e958d6af85a4793bced96e 100644
> --- a/include/linux/smp.h
> +++ b/include/linux/smp.h
> @@ -19,7 +19,7 @@ struct call_single_data {
>  	smp_call_func_t func;
>  	void *info;
>  	unsigned int flags;
> -};
> +} __attribute__((aligned(4 * sizeof(void *))));

Agreed.

  reply	other threads:[~2017-08-02 10:53 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-02  8:52 [PATCH 0/3] " Huang, Ying
2017-08-02  8:52 ` [PATCH 1/3] percpu: Add alloc_percpu_aligned() Huang, Ying
2017-08-02 13:50   ` Christopher Lameter
2017-08-03  0:33     ` Huang, Ying
2017-08-02  8:52 ` [PATCH 2/3] iova: Use alloc_percpu_aligned() Huang, Ying
2017-08-02  8:52 ` [PATCH 3/3] IPI: Avoid to use 2 cache lines for one call_single_data Huang, Ying
2017-08-02 10:18   ` Eric Dumazet
2017-08-02 10:53     ` Peter Zijlstra [this message]
2017-08-03  8:35     ` Huang, Ying
2017-08-03  8:57       ` Peter Zijlstra
2017-08-04  1:28         ` Huang, Ying
2017-08-04  2:05           ` Huang, Ying
2017-08-04  9:27             ` Peter Zijlstra
2017-08-05  0:47               ` Huang, Ying
2017-08-07  8:28                 ` Peter Zijlstra
2017-08-08  4:30                   ` Huang, Ying
2017-08-14  5:44                     ` Huang, Ying
2017-08-28  5:19                       ` Huang, Ying
2017-08-28  8:49                         ` Peter Zijlstra
2017-08-29 14:23                     ` [tip:locking/core] smp: Avoid using two cache lines for struct call_single_data tip-bot for Ying Huang
2017-08-04  9:20           ` [PATCH 3/3] IPI: Avoid to use 2 cache lines for one call_single_data Peter Zijlstra
2017-08-02 13:54 ` [PATCH 0/3] " Christopher Lameter

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