From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DEABFC432C3 for ; Wed, 13 Nov 2019 19:01:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 37EB9206CB for ; Wed, 13 Nov 2019 19:01:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727468AbfKMTBX (ORCPT ); Wed, 13 Nov 2019 14:01:23 -0500 Received: from mga14.intel.com ([192.55.52.115]:44447 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727290AbfKMTBX (ORCPT ); Wed, 13 Nov 2019 14:01:23 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Nov 2019 11:01:21 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,301,1569308400"; d="scan'208";a="355563182" Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by orsmga004.jf.intel.com with ESMTP; 13 Nov 2019 11:01:18 -0800 Date: Wed, 13 Nov 2019 11:01:17 -0800 From: Ira Weiny To: John Hubbard Cc: Andrew Morton , Al Viro , Alex Williamson , Benjamin Herrenschmidt , =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= , Christoph Hellwig , Dan Williams , Daniel Vetter , Dave Chinner , David Airlie , "David S . Miller" , Jan Kara , Jason Gunthorpe , Jens Axboe , Jonathan Corbet , =?iso-8859-1?B?Suly9G1l?= Glisse , Magnus Karlsson , Mauro Carvalho Chehab , Michael Ellerman , Michal Hocko , Mike Kravetz , Paul Mackerras , Shuah Khan , Vlastimil Babka , bpf@vger.kernel.org, dri-devel@lists.freedesktop.org, kvm@vger.kernel.org, linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-media@vger.kernel.org, linux-rdma@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-mm@kvack.org, LKML Subject: Re: [PATCH v4 20/23] mm/gup_benchmark: use proper FOLL_WRITE flags instead of hard-coding "1" Message-ID: <20191113190116.GA12947@iweiny-DESK2.sc.intel.com> References: <20191113042710.3997854-1-jhubbard@nvidia.com> <20191113042710.3997854-21-jhubbard@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191113042710.3997854-21-jhubbard@nvidia.com> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, Nov 12, 2019 at 08:27:07PM -0800, John Hubbard wrote: > Fix the gup benchmark flags to use the symbolic FOLL_WRITE, > instead of a hard-coded "1" value. > > Also, clean up the filtering of gup flags a little, by just doing > it once before issuing any of the get_user_pages*() calls. This > makes it harder to overlook, instead of having little "gup_flags & 1" > phrases in the function calls. > > Signed-off-by: John Hubbard Reviewed-by: Ira Weiny > --- > mm/gup_benchmark.c | 9 ++++++--- > tools/testing/selftests/vm/gup_benchmark.c | 6 +++++- > 2 files changed, 11 insertions(+), 4 deletions(-) > > diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c > index 7dd602d7f8db..7fc44d25eca7 100644 > --- a/mm/gup_benchmark.c > +++ b/mm/gup_benchmark.c > @@ -48,18 +48,21 @@ static int __gup_benchmark_ioctl(unsigned int cmd, > nr = (next - addr) / PAGE_SIZE; > } > > + /* Filter out most gup flags: only allow a tiny subset here: */ > + gup->flags &= FOLL_WRITE; > + > switch (cmd) { > case GUP_FAST_BENCHMARK: > - nr = get_user_pages_fast(addr, nr, gup->flags & 1, > + nr = get_user_pages_fast(addr, nr, gup->flags, > pages + i); > break; > case GUP_LONGTERM_BENCHMARK: > nr = get_user_pages(addr, nr, > - (gup->flags & 1) | FOLL_LONGTERM, > + gup->flags | FOLL_LONGTERM, > pages + i, NULL); > break; > case GUP_BENCHMARK: > - nr = get_user_pages(addr, nr, gup->flags & 1, pages + i, > + nr = get_user_pages(addr, nr, gup->flags, pages + i, > NULL); > break; > default: > diff --git a/tools/testing/selftests/vm/gup_benchmark.c b/tools/testing/selftests/vm/gup_benchmark.c > index 485cf06ef013..389327e9b30a 100644 > --- a/tools/testing/selftests/vm/gup_benchmark.c > +++ b/tools/testing/selftests/vm/gup_benchmark.c > @@ -18,6 +18,9 @@ > #define GUP_LONGTERM_BENCHMARK _IOWR('g', 2, struct gup_benchmark) > #define GUP_BENCHMARK _IOWR('g', 3, struct gup_benchmark) > > +/* Just the flags we need, copied from mm.h: */ > +#define FOLL_WRITE 0x01 /* check pte is writable */ > + > struct gup_benchmark { > __u64 get_delta_usec; > __u64 put_delta_usec; > @@ -85,7 +88,8 @@ int main(int argc, char **argv) > } > > gup.nr_pages_per_call = nr_pages; > - gup.flags = write; > + if (write) > + gup.flags |= FOLL_WRITE; > > fd = open("/sys/kernel/debug/gup_benchmark", O_RDWR); > if (fd == -1) > -- > 2.24.0 >