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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 249BBC43381 for ; Tue, 26 Feb 2019 07:52:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E60F92173C for ; Tue, 26 Feb 2019 07:52:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727093AbfBZHwq (ORCPT ); Tue, 26 Feb 2019 02:52:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38918 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726718AbfBZHwq (ORCPT ); Tue, 26 Feb 2019 02:52:46 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6F5E3308FF29; Tue, 26 Feb 2019 07:52:45 +0000 (UTC) Received: from xz-x1 (dhcp-14-116.nay.redhat.com [10.66.14.116]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BEAD2600C0; Tue, 26 Feb 2019 07:52:36 +0000 (UTC) Date: Tue, 26 Feb 2019 15:52:34 +0800 From: Peter Xu To: Mike Rapoport Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand , Hugh Dickins , Maya Gokhale , Jerome Glisse , Pavel Emelyanov , Johannes Weiner , Martin Cracauer , Shaohua Li , Marty McFadden , Andrea Arcangeli , Mike Kravetz , Denis Plotnikov , Mike Rapoport , Mel Gorman , "Kirill A . Shutemov" , "Dr . David Alan Gilbert" Subject: Re: [PATCH v2 26/26] userfaultfd: selftests: add write-protect test Message-ID: <20190226075234.GN13653@xz-x1> References: <20190212025632.28946-1-peterx@redhat.com> <20190212025632.28946-27-peterx@redhat.com> <20190226065836.GD5873@rapoport-lnx> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190226065836.GD5873@rapoport-lnx> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Tue, 26 Feb 2019 07:52:46 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 26, 2019 at 08:58:36AM +0200, Mike Rapoport wrote: > On Tue, Feb 12, 2019 at 10:56:32AM +0800, Peter Xu wrote: > > This patch adds uffd tests for write protection. > > > > Instead of introducing new tests for it, let's simply squashing uffd-wp > > tests into existing uffd-missing test cases. Changes are: > > > > (1) Bouncing tests > > > > We do the write-protection in two ways during the bouncing test: > > > > - By using UFFDIO_COPY_MODE_WP when resolving MISSING pages: then > > we'll make sure for each bounce process every single page will be > > at least fault twice: once for MISSING, once for WP. > > > > - By direct call UFFDIO_WRITEPROTECT on existing faulted memories: > > To further torture the explicit page protection procedures of > > uffd-wp, we split each bounce procedure into two halves (in the > > background thread): the first half will be MISSING+WP for each > > page as explained above. After the first half, we write protect > > the faulted region in the background thread to make sure at least > > half of the pages will be write protected again which is the first > > half to test the new UFFDIO_WRITEPROTECT call. Then we continue > > with the 2nd half, which will contain both MISSING and WP faulting > > tests for the 2nd half and WP-only faults from the 1st half. > > > > (2) Event/Signal test > > > > Mostly previous tests but will do MISSING+WP for each page. For > > sigbus-mode test we'll need to provide standalone path to handle the > > write protection faults. > > > > For all tests, do statistics as well for uffd-wp pages. > > > > Signed-off-by: Peter Xu > > --- > > tools/testing/selftests/vm/userfaultfd.c | 154 ++++++++++++++++++----- > > 1 file changed, 126 insertions(+), 28 deletions(-) > > > > diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c > > index e5d12c209e09..57b5ac02080a 100644 > > --- a/tools/testing/selftests/vm/userfaultfd.c > > +++ b/tools/testing/selftests/vm/userfaultfd.c > > @@ -56,6 +56,7 @@ > > #include > > #include > > #include > > +#include > > > > #include "../kselftest.h" > > > > @@ -78,6 +79,8 @@ static int test_type; > > #define ALARM_INTERVAL_SECS 10 > > static volatile bool test_uffdio_copy_eexist = true; > > static volatile bool test_uffdio_zeropage_eexist = true; > > +/* Whether to test uffd write-protection */ > > +static bool test_uffdio_wp = false; > > > > static bool map_shared; > > static int huge_fd; > > @@ -92,6 +95,7 @@ pthread_attr_t attr; > > struct uffd_stats { > > int cpu; > > unsigned long missing_faults; > > + unsigned long wp_faults; > > }; > > > > /* pthread_mutex_t starts at page offset 0 */ > > @@ -141,9 +145,29 @@ static void uffd_stats_reset(struct uffd_stats *uffd_stats, > > for (i = 0; i < n_cpus; i++) { > > uffd_stats[i].cpu = i; > > uffd_stats[i].missing_faults = 0; > > + uffd_stats[i].wp_faults = 0; > > } > > } > > > > +static void uffd_stats_report(struct uffd_stats *stats, int n_cpus) > > +{ > > + int i; > > + unsigned long long miss_total = 0, wp_total = 0; > > + > > + for (i = 0; i < n_cpus; i++) { > > + miss_total += stats[i].missing_faults; > > + wp_total += stats[i].wp_faults; > > + } > > + > > + printf("userfaults: %llu missing (", miss_total); > > + for (i = 0; i < n_cpus; i++) > > + printf("%lu+", stats[i].missing_faults); > > + printf("\b), %llu wp (", wp_total); > > + for (i = 0; i < n_cpus; i++) > > + printf("%lu+", stats[i].wp_faults); > > + printf("\b)\n"); > > +} > > + > > static int anon_release_pages(char *rel_area) > > { > > int ret = 0; > > @@ -264,19 +288,15 @@ struct uffd_test_ops { > > void (*alias_mapping)(__u64 *start, size_t len, unsigned long offset); > > }; > > > > -#define ANON_EXPECTED_IOCTLS ((1 << _UFFDIO_WAKE) | \ > > - (1 << _UFFDIO_COPY) | \ > > - (1 << _UFFDIO_ZEROPAGE)) > > - > > static struct uffd_test_ops anon_uffd_test_ops = { > > - .expected_ioctls = ANON_EXPECTED_IOCTLS, > > + .expected_ioctls = UFFD_API_RANGE_IOCTLS, > > .allocate_area = anon_allocate_area, > > .release_pages = anon_release_pages, > > .alias_mapping = noop_alias_mapping, > > }; > > > > static struct uffd_test_ops shmem_uffd_test_ops = { > > - .expected_ioctls = ANON_EXPECTED_IOCTLS, > > + .expected_ioctls = UFFD_API_RANGE_IOCTLS, > > Isn't UFFD_API_RANGE_IOCTLS includes UFFDIO_WP which is not supported for > shmem? Yes it didn't fail the test case probably because the test case only registers the shmem region with UFFDIO_REGISTER_MODE_MISSING, and for now we'll simply blindly return the _UFFDIO_WRITEPROTECT capability if the register ioctl succeeded. However it'll still fail the UFFDIO_REGISTER ioctl directly if someone requests with UFFDIO_REGISTER_MODE_WP mode upon shmem. So maybe I should explicitly remove the _UFFDIO_WRITEPROTECT bit in userfaultfd_register() if I detected any non-anonymous regions? Then here I will revert to ANON_EXPECTED_IOCTLS for shmem_uffd_test_ops in the tests. > > > .allocate_area = shmem_allocate_area, > > .release_pages = shmem_release_pages, > > .alias_mapping = noop_alias_mapping, > > ... > > -- > Sincerely yours, > Mike. > Regards, -- Peter Xu