From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934385AbdDSM5q (ORCPT ); Wed, 19 Apr 2017 08:57:46 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:29288 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763322AbdDSM42 (ORCPT ); Wed, 19 Apr 2017 08:56:28 -0400 Message-Id: <22c2ebcfe72f4f17be6d284d922895cec34e23fc.1492606297.git.christophe.leroy@c-s.fr> In-Reply-To: References: From: Christophe Leroy Subject: [PATCH 1/5] powerpc/mm: only call store_updates_sp() on stores in do_page_fault() To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Scott Wood Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Date: Wed, 19 Apr 2017 14:56:24 +0200 (CEST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Function store_updates_sp() checks whether the faulting instruction is a store updating r1. Therefore we can limit its calls to stores exceptions. This patch is an improvement of commit a7a9dcd882a67 ("powerpc: Avoid taking a data miss on every userspace instruction miss") With the same microbenchmark app, run with 500 as argument, on an MPC885 we get: Before this patch: 152000 DTLB misses After this patch: 147000 DTLB misses Signed-off-by: Christophe Leroy --- arch/powerpc/mm/fault.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 3a7d580fdc59..67fefb59d40e 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -287,7 +287,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, * can result in fault, which will cause a deadlock when called with * mmap_sem held */ - if (!is_exec && user_mode(regs)) + if (is_write && user_mode(regs)) store_update_sp = store_updates_sp(regs); if (user_mode(regs)) -- 2.12.0