From: Tejun Heo <tj@kernel.org>
To: Brian Gerst <brgerst@gmail.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] x86, percpu: Optimize this_cpu_ptr
Date: Sun, 05 Sep 2010 11:20:45 +0200 [thread overview]
Message-ID: <4C8360ED.8070700@kernel.org> (raw)
In-Reply-To: <1283620871-818-2-git-send-email-brgerst@gmail.com>
Hello,
On 09/04/2010 07:21 PM, Brian Gerst wrote:
> diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
> index cd28f9a..d854438 100644
> --- a/arch/x86/include/asm/percpu.h
> +++ b/arch/x86/include/asm/percpu.h
> @@ -47,6 +47,15 @@
> #ifdef CONFIG_SMP
> #define __percpu_arg(x) "%%"__stringify(__percpu_seg)":%P" #x
> #define __my_cpu_offset percpu_read(this_cpu_off)
> +#define __this_cpu_ptr(ptr) \
> +({ \
> + typeof(ptr) __ptr = (ptr); \
> + __verify_pcpu_ptr(ptr); \
> + asm volatile("add " __percpu_arg(1) ", %0" \
> + : "+r" (__ptr) \
> + : "m" (this_cpu_off)); \
> + __ptr; \
> +})
Great, thanks for doing this, but can you please comment on what
__this_cpu_ptr() optimizes above? Something similar to the patch
description but shorter.
Thanks.
--
tejun
next prev parent reply other threads:[~2010-09-05 9:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-04 17:21 PATCH [0/2] percpu: Local cpu pointer optimizations Brian Gerst
2010-09-04 17:21 ` [PATCH 1/2] x86, percpu: Optimize this_cpu_ptr Brian Gerst
2010-09-05 9:20 ` Tejun Heo [this message]
2010-09-04 17:21 ` [PATCH 2/2] percpu: Optimize __get_cpu_var() Brian Gerst
-- strict thread matches above, loose matches on Subject: below --
2010-09-07 11:41 PATCH [0/2] percpu: Local cpu pointer optimizations Brian Gerst
2010-09-07 11:41 ` [PATCH 1/2] x86, percpu: Optimize this_cpu_ptr Brian Gerst
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