From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id 07C896B0089 for ; Tue, 30 Nov 2010 14:29:57 -0500 (EST) Received: by wwb29 with SMTP id 29so24818wwb.26 for ; Tue, 30 Nov 2010 11:29:55 -0800 (PST) Subject: Re: [thisops uV3 07/18] highmem: Use this_cpu_xx_return() operations From: Eric Dumazet In-Reply-To: References: <20101130190707.457099608@linux.com> <20101130190845.216537525@linux.com> <1291144408.2904.232.camel@edumazet-laptop> Content-Type: text/plain; charset="UTF-8" Date: Tue, 30 Nov 2010 20:29:51 +0100 Message-ID: <1291145391.2904.247.camel@edumazet-laptop> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: akpm@linux-foundation.org, Pekka Enberg , Peter Zijlstra , Catalin Marinas , linux-kernel@vger.kernel.org, Mathieu Desnoyers , Tejun Heo , linux-mm@kvack.org List-ID: Le mardi 30 novembre 2010 A 13:26 -0600, Christoph Lameter a A(C)crit : > On Tue, 30 Nov 2010, Eric Dumazet wrote: > > > > { > > > - int idx = --__get_cpu_var(__kmap_atomic_idx); > > > + int idx = __this_cpu_dec_return(__kmap_atomic_idx); > > > > __this_cpu_dec_return() is only needed if CONFIG_DEBUG_HIGHMEM > > > > > #ifdef CONFIG_DEBUG_HIGHMEM > > > BUG_ON(idx < 0); > > > #endif > > > > > > > You could change kmap_atomic_idx_pop() to return void, and use > > __this_cpu_dec(__kmap_atomic_idx) > > The following would do? > > > Subject: highmem: Use this_cpu_dec instead of __this_cpu_dec_return if !DEBUG_HIGHMEM > > Signed-off-by: Christoph Lameter > > --- > include/linux/highmem.h | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > Index: linux-2.6/include/linux/highmem.h > =================================================================== > --- linux-2.6.orig/include/linux/highmem.h 2010-11-30 13:23:44.000000000 -0600 > +++ linux-2.6/include/linux/highmem.h 2010-11-30 13:24:54.000000000 -0600 > @@ -95,14 +95,19 @@ static inline int kmap_atomic_idx(void) > return __this_cpu_read(__kmap_atomic_idx) - 1; > } > > +#ifdef CONFIG_DEBUG_HIGHMEM > static inline int kmap_atomic_idx_pop(void) > { > int idx = __this_cpu_dec_return(__kmap_atomic_idx); > -#ifdef CONFIG_DEBUG_HIGHMEM > BUG_ON(idx < 0); > -#endif > return idx; > } > +#else > +static inline void kmap_atomic_idx_pop(void) > +{ > + __this_cpu_dec(__kmap_atomic_idx); > +} > +#endif > > #endif > well maybe a single prototype ;) static inline void kmap_atomic_idx_pop(void) { #ifdef CONFIG_DEBUG_HIGHMEM int idx = __this_cpu_dec_return(__kmap_atomic_idx); BUG_ON(idx < 0); #else __this_cpu_dec(__kmap_atomic_idx); #endif } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org