Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1167625AbdDXJLd (ORCPT ); Mon, 24 Apr 2017 05:11:33 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:54690 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1167516AbdDXJLZ (ORCPT ); Mon, 24 Apr 2017 05:11:25 -0400 From: "Aneesh Kumar K.V" To: Christophe Leroy , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Scott Wood Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 1/5] powerpc/mm: only call store_updates_sp() on stores in do_page_fault() In-Reply-To: <22c2ebcfe72f4f17be6d284d922895cec34e23fc.1492606297.git.christophe.leroy@c-s.fr> References: <22c2ebcfe72f4f17be6d284d922895cec34e23fc.1492606297.git.christophe.leroy@c-s.fr> Date: Mon, 24 Apr 2017 14:40:27 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: disable x-cbid: 17042409-0048-0000-0000-0000022205D1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17042409-0049-0000-0000-000047CFAC15 Message-Id: <87zif6188s.fsf@skywalker.in.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-24_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1703280000 definitions=main-1704240159 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1249 Lines: 38 Christophe Leroy writes: > 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 > Reviewed-by: Aneesh Kumar K.V > 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