From: Christoph Lameter <cl@linux.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org
Subject: Re: percpu: Implement this_cpu_add,sub,dec,inc_return
Date: Fri, 19 Nov 2010 11:09:36 -0600 (CST) [thread overview]
Message-ID: <alpine.DEB.2.00.1011191108240.3976@router.home> (raw)
In-Reply-To: <1290183158.3034.145.camel@edumazet-laptop>
On Fri, 19 Nov 2010, Eric Dumazet wrote:
> By the way, is your patch really ok ?
>
> xadd %0,foo returns in %0 the previous value of the memory, not the
> value _after_ the operation.
>
> This is why we do in arch/x86/include/asm/atomic.h :
>
> static inline int atomic_add_return(int i, atomic_t *v)
> ...
>
> __i = i;
> asm volatile(LOCK_PREFIX "xaddl %0, %1"
> : "+r" (i), "+m" (v->counter)
> : : "memory");
> return i + __i;
> ...
Ok so rename the macros to this_cpu_return_inc/dec/add/sub?
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next prev parent reply other threads:[~2010-11-19 17:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-09 17:27 vmstat: Optimize zone counter modifications through the use of this cpu operations Christoph Lameter
2010-11-10 15:40 ` percpu: Implement this_cpu_add,sub,dec,inc_return Christoph Lameter
2010-11-17 18:28 ` Eric Dumazet
2010-11-19 15:42 ` Christoph Lameter
2010-11-19 15:51 ` Eric Dumazet
2010-11-19 15:59 ` Christoph Lameter
2010-11-19 16:12 ` Eric Dumazet
2010-11-19 17:09 ` Christoph Lameter [this message]
2010-11-19 17:59 ` Christoph Lameter
2010-11-20 9:50 ` Eric Dumazet
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