From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752471Ab0KZVJ7 (ORCPT ); Fri, 26 Nov 2010 16:09:59 -0500 Received: from smtp108.prem.mail.ac4.yahoo.com ([76.13.13.47]:23907 "HELO smtp108.prem.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751938Ab0KZVJz (ORCPT ); Fri, 26 Nov 2010 16:09:55 -0500 X-Yahoo-SMTP: _Dag8S.swBC1p4FJKLCXbs8NQzyse1SYSgnAbY0- X-YMail-OSG: 9b7YwBcVM1kGbo2Kh15P5ZzFQF9Bd6UykKFIVdCWt36nkJ. owbGA9kbaL_RNL6e1KiBSUZ2AEyaFACNTqhIeaMJPx3AubzA5GuG7bmceCl_ G9piNJshmlPvK6qdyxZWazCL65tjHGZxEmWIMUjVetVzxKo6YKIVGuriDQqI oBwGiibmXKadXdLDrtnz.hxuXp6A.iGe3QGLoeNTj8LHaRpivZYgs4Dy6fq2 yX5aKixN6H9Bdu8lNpG_zzg9ugUn16JNYOOVuzF2ulXYvCE.LhoqKGa5RDKv T_jV5xHM23XngDGTVfKBq X-Yahoo-Newman-Property: ymail-3 Message-Id: <20101126210953.017559817@linux.com> User-Agent: quilt/0.48-1 Date: Fri, 26 Nov 2010 15:09:44 -0600 From: Christoph Lameter To: akpm@linux-foundation.org Cc: Pekka Enberg Cc: linux-kernel@vger.kernel.org Cc: Eric Dumazet Cc: Mathieu Desnoyers Cc: Tejun Heo Subject: [thisops uV2 07/10] highmem: Use this_cpu_xx_return() operations References: <20101126210937.383047168@linux.com> Content-Disposition: inline; filename=highmem Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use this_cpu operations to optimize access primitives for highmem. The main effect is the avoidance of address calculations through the use of a segment prefix. Signed-off-by: Christoph Lameter --- include/linux/highmem.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) Index: linux-2.6/include/linux/highmem.h =================================================================== --- linux-2.6.orig/include/linux/highmem.h 2010-11-22 14:43:40.000000000 -0600 +++ linux-2.6/include/linux/highmem.h 2010-11-22 14:45:02.000000000 -0600 @@ -81,7 +81,8 @@ DECLARE_PER_CPU(int, __kmap_atomic_idx); static inline int kmap_atomic_idx_push(void) { - int idx = __get_cpu_var(__kmap_atomic_idx)++; + int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1; + #ifdef CONFIG_DEBUG_HIGHMEM WARN_ON_ONCE(in_irq() && !irqs_disabled()); BUG_ON(idx > KM_TYPE_NR); @@ -91,12 +92,12 @@ static inline int kmap_atomic_idx_push(v static inline int kmap_atomic_idx(void) { - return __get_cpu_var(__kmap_atomic_idx) - 1; + return __this_cpu_read(__kmap_atomic_idx) - 1; } static inline int kmap_atomic_idx_pop(void) { - int idx = --__get_cpu_var(__kmap_atomic_idx); + int idx = __this_cpu_dec_return(__kmap_atomic_idx); #ifdef CONFIG_DEBUG_HIGHMEM BUG_ON(idx < 0); #endif