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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,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 CA9B5C433E0 for ; Sun, 24 Jan 2021 23:18:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4A81F229C7 for ; Sun, 24 Jan 2021 23:18:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4A81F229C7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B83666B0005; Sun, 24 Jan 2021 18:18:47 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B0B936B0007; Sun, 24 Jan 2021 18:18:47 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9D56A6B0008; Sun, 24 Jan 2021 18:18:47 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0162.hostedemail.com [216.40.44.162]) by kanga.kvack.org (Postfix) with ESMTP id 7FFFC6B0005 for ; Sun, 24 Jan 2021 18:18:47 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 484828249980 for ; Sun, 24 Jan 2021 23:18:47 +0000 (UTC) X-FDA: 77742235494.26.owl51_3d0678f27581 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id 260091804B656 for ; Sun, 24 Jan 2021 23:18:47 +0000 (UTC) X-HE-Tag: owl51_3d0678f27581 X-Filterd-Recvd-Size: 6963 Received: from hqnvemgate26.nvidia.com (hqnvemgate26.nvidia.com [216.228.121.65]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Sun, 24 Jan 2021 23:18:46 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Sun, 24 Jan 2021 15:18:45 -0800 Received: from [10.2.52.243] (172.20.145.6) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Sun, 24 Jan 2021 23:18:39 +0000 Subject: Re: [PATCH v7 14/14] selftests/vm: test faulting in kernel, and verify pinnable pages To: Pavel Tatashin , , , , , , , , , , , , , , , , , , , , , , References: <20210122033748.924330-1-pasha.tatashin@soleen.com> <20210122033748.924330-15-pasha.tatashin@soleen.com> From: John Hubbard Message-ID: <532b1927-1b5d-83e8-f1f9-50cd5e72435f@nvidia.com> Date: Sun, 24 Jan 2021 15:18:38 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:85.0) Gecko/20100101 Thunderbird/85.0 MIME-Version: 1.0 In-Reply-To: <20210122033748.924330-15-pasha.tatashin@soleen.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL101.nvidia.com (172.20.187.10) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1611530325; bh=yU8511hV57P0w7d0jPjk2t0wmPLj/hsWdLqeK4Z4aAk=; h=Subject:To:References:From:Message-ID:Date:User-Agent: MIME-Version:In-Reply-To:Content-Type:Content-Language: Content-Transfer-Encoding:X-Originating-IP:X-ClientProxiedBy; b=n1b89sXKmnkyYyciV/4pAGy8Y58mJ6yJ142H0nA84BqmnOq/hxmtl49/egxvw1DMY 7bUJwehU2KcZj00/0w18vL04z7fvUBaxyxDraB1sVzSBdnb21IUbBw2TUeBXSStgT/ FhsI5jgRpxM+PRz7uZMfpS0rtpJTZ4XWr4ccsf3LUXdqmUZN6n4+fucqeN4X+YTltq 81lDtJJV4kuUSTTrV7TNdllpCPYxOxnXGCRm2hoNr023ijTO+8MJNiUowIi8sLmrWP C1lXjH1tU9wM+YJY0lXHgOmBh35wwr1R+JR/UszDdQw3Q6NrSHqrsWiHzpjMJXDH5J RwAubw3Gh9xyQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 1/21/21 7:37 PM, Pavel Tatashin wrote: > When pages are pinned they can be faulted in userland and migrated, and > they can be faulted right in kernel without migration. > > In either case, the pinned pages must end-up being pinnable (not movable). > > Add a new test to gup_test, to help verify that the gup/pup > (get_user_pages() / pin_user_pages()) behavior with respect to pinnable > and movable pages is reasonable and correct. Specifically, provide a > way to: > > 1) Verify that only "pinnable" pages are pinned. This is checked > automatically for you. > > 2) Verify that gup/pup performance is reasonable. This requires > comparing benchmarks between doing gup/pup on pages that have been > pre-faulted in from user space, vs. doing gup/pup on pages that are not > faulted in until gup/pup time (via FOLL_TOUCH). This decision is > controlled with the new -z command line option. > > Signed-off-by: Pavel Tatashin > --- > mm/gup_test.c | 6 ++++++ > tools/testing/selftests/vm/gup_test.c | 23 +++++++++++++++++++---- > 2 files changed, 25 insertions(+), 4 deletions(-) > This also looks good. I do see the WARN_ON_ONCE firing in internal_get_user_pages_fast(), when running with *only* the new -z option. I'll poke around the rest of the patchset and see if that is expected and normal, but either way the test code itself looks correct and seems to be passing my set of "run a bunch of different gup_test options" here, so feel free to add: Reviewed-by: John Hubbard thanks, -- John Hubbard NVIDIA > diff --git a/mm/gup_test.c b/mm/gup_test.c > index a6ed1c877679..d974dec19e1c 100644 > --- a/mm/gup_test.c > +++ b/mm/gup_test.c > @@ -52,6 +52,12 @@ static void verify_dma_pinned(unsigned int cmd, struct page **pages, > > dump_page(page, "gup_test failure"); > break; > + } else if (cmd == PIN_LONGTERM_BENCHMARK && > + WARN(!is_pinnable_page(page), > + "pages[%lu] is NOT pinnable but pinned\n", > + i)) { > + dump_page(page, "gup_test failure"); > + break; > } > } > break; > diff --git a/tools/testing/selftests/vm/gup_test.c b/tools/testing/selftests/vm/gup_test.c > index 943cc2608dc2..1e662d59c502 100644 > --- a/tools/testing/selftests/vm/gup_test.c > +++ b/tools/testing/selftests/vm/gup_test.c > @@ -13,6 +13,7 @@ > > /* Just the flags we need, copied from mm.h: */ > #define FOLL_WRITE 0x01 /* check pte is writable */ > +#define FOLL_TOUCH 0x02 /* mark page accessed */ > > static char *cmd_to_str(unsigned long cmd) > { > @@ -39,11 +40,11 @@ int main(int argc, char **argv) > unsigned long size = 128 * MB; > int i, fd, filed, opt, nr_pages = 1, thp = -1, repeats = 1, write = 1; > unsigned long cmd = GUP_FAST_BENCHMARK; > - int flags = MAP_PRIVATE; > + int flags = MAP_PRIVATE, touch = 0; > char *file = "/dev/zero"; > char *p; > > - while ((opt = getopt(argc, argv, "m:r:n:F:f:abctTLUuwWSHp")) != -1) { > + while ((opt = getopt(argc, argv, "m:r:n:F:f:abctTLUuwWSHpz")) != -1) { > switch (opt) { > case 'a': > cmd = PIN_FAST_BENCHMARK; > @@ -110,6 +111,10 @@ int main(int argc, char **argv) > case 'H': > flags |= (MAP_HUGETLB | MAP_ANONYMOUS); > break; > + case 'z': > + /* fault pages in gup, do not fault in userland */ > + touch = 1; > + break; > default: > return -1; > } > @@ -167,8 +172,18 @@ int main(int argc, char **argv) > else if (thp == 0) > madvise(p, size, MADV_NOHUGEPAGE); > > - for (; (unsigned long)p < gup.addr + size; p += PAGE_SIZE) > - p[0] = 0; > + /* > + * FOLL_TOUCH, in gup_test, is used as an either/or case: either > + * fault pages in from the kernel via FOLL_TOUCH, or fault them > + * in here, from user space. This allows comparison of performance > + * between those two cases. > + */ > + if (touch) { > + gup.gup_flags |= FOLL_TOUCH; > + } else { > + for (; (unsigned long)p < gup.addr + size; p += PAGE_SIZE) > + p[0] = 0; > + } > > /* Only report timing information on the *_BENCHMARK commands: */ > if ((cmd == PIN_FAST_BENCHMARK) || (cmd == GUP_FAST_BENCHMARK) || >