Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754870AbYFDAab (ORCPT ); Tue, 3 Jun 2008 20:30:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752107AbYFDAaW (ORCPT ); Tue, 3 Jun 2008 20:30:22 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:38240 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751753AbYFDAaV (ORCPT ); Tue, 3 Jun 2008 20:30:21 -0400 Message-Id: <20080604003018.538497000@polaris-admin.engr.sgi.com> User-Agent: quilt/0.46-1 Date: Tue, 03 Jun 2008 17:30:18 -0700 From: Mike Travis To: Ingo Molnar Cc: Andrew Morton , Christoph Lameter , David Miller , Eric Dumazet , Jeremy Fitzhardinge , linux-kernel@vger.kernel.org Subject: [PATCH 0/4] percpu: Optimize percpu accesses Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1748 Lines: 45 This patchset provides the following: * Generic: Percpu infrastructure to rebase the per cpu area to zero This provides for the capability of accessing the percpu variables using a local register instead of having to go through a table on node 0 to find the cpu-specific offsets. It also would allow atomic operations on percpu variables to reduce required locking. Uses a new config var HAVE_ZERO_BASED_PER_CPU to indicate to the generic code that the arch has this new basing. * x86_64: Fold pda into per cpu area Declare the pda as a per cpu variable. This will move the pda area to an address accessible by the x86_64 per cpu macros. Subtraction of __per_cpu_start will make the offset based from the beginning of the per cpu area. Since %gs is pointing to the pda, it will then also point to the per cpu variables and can be accessed thusly: %gs:[&per_cpu_xxxx - __per_cpu_start] * x86_64: Rebase per cpu variables to zero Take advantage of the zero-based per cpu area provided above. Then we can directly use the x86_32 percpu operations. x86_32 offsets %fs by __per_cpu_start. x86_64 has %gs pointing directly to the pda and the per cpu area thereby allowing access to the pda with the x86_64 pda operations and access to the per cpu variables using x86_32 percpu operations. Based on linux-2.6.tip Signed-off-by: Christoph Lameter Signed-off-by: Mike Travis --- -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/