From: "Huang\, Ying" <ying.huang@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Huang\, Ying" <ying.huang@intel.com>,
Eric Dumazet <eric.dumazet@gmail.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: Fri, 04 Aug 2017 09:28:17 +0800 [thread overview]
Message-ID: <87wp6kyvda.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <20170803085752.yrqox3kwrvkj544a@hirez.programming.kicks-ass.net> (Peter Zijlstra's message of "Thu, 3 Aug 2017 10:57:52 +0200")
Peter Zijlstra <peterz@infradead.org> writes:
[snip]
> diff --git a/include/linux/smp.h b/include/linux/smp.h
> index 68123c1fe549..8d817cb80a38 100644
> --- a/include/linux/smp.h
> +++ b/include/linux/smp.h
> @@ -14,13 +14,16 @@
> #include <linux/llist.h>
>
> typedef void (*smp_call_func_t)(void *info);
> -struct call_single_data {
> +struct __call_single_data {
> struct llist_node llist;
> smp_call_func_t func;
> void *info;
> unsigned int flags;
> };
>
> +typedef struct __call_single_data call_single_data_t
> + __aligned(sizeof(struct __call_single_data));
> +
Another requirement of the alignment is that it should be the power of
2. Otherwise, for example, if someone adds a field to struct, so that
the size becomes 40 on x86_64. The alignment should be 64 instead of
40.
Best Regards,
Huang, Ying
> /* total number of cpus in this system (may exceed NR_CPUS) */
> extern unsigned int total_cpus;
>
[snip]
next prev parent reply other threads:[~2017-08-04 1:28 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-02 8:52 [PATCH 0/3] IPI: Avoid to use 2 cache lines for one call_single_data 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
2017-08-03 8:35 ` Huang, Ying
2017-08-03 8:57 ` Peter Zijlstra
2017-08-04 1:28 ` Huang, Ying [this message]
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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