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=-15.2 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 8BA97C433E0 for ; Thu, 4 Feb 2021 21:08:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8854664FA4 for ; Thu, 4 Feb 2021 21:08:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8854664FA4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 053336B006C; Thu, 4 Feb 2021 16:08:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F1EF16B0070; Thu, 4 Feb 2021 16:08:17 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DC0366B0071; Thu, 4 Feb 2021 16:08:17 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0240.hostedemail.com [216.40.44.240]) by kanga.kvack.org (Postfix) with ESMTP id BF3B16B006C for ; Thu, 4 Feb 2021 16:08:17 -0500 (EST) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 8AC3A180AD81F for ; Thu, 4 Feb 2021 21:08:17 +0000 (UTC) X-FDA: 77781823434.30.sea74_600ccd8275df Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id 6C5B7180B3C83 for ; Thu, 4 Feb 2021 21:08:17 +0000 (UTC) X-HE-Tag: sea74_600ccd8275df X-Filterd-Recvd-Size: 5927 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Thu, 4 Feb 2021 21:08:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description; bh=/6flMUs4q/9e4K9Y4oNKr3UzQiLVqc1VXmMcTE8n99U=; b=1MUnI9zX+7iDTvEFR0Pt6icYxu mZ0ZyOaeDZsskWkqJeU7vtB0JnCkIOLZyfNXASIxi0b4QTf5IaRht1p94TCyh3zegg2ykVxwoY5Zh +unY6QrqC1Mr60qKAWBi0wN/j8dzfalXVyy2Itpw/nxhPi4S4KqVafbacIx5ejEXJoTmPZBz24wVA O/DZiE8A+2YvwFWzzW94kinajywJXZCDfRceMOxs3+LCZbtohSXpQ4seC/yBmnE8fTy3PL4xfE8ed X+2ju8NWiVdnoHmvi2aIjYxPzuPcRnLVZ8SdWx4pl+NwEn8QDhZ36x13b8CqXDTCX1T5yxCLcVoF9 sAGB1qSg==; Received: from [2601:1c0:6280:3f0::aec2] by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1l7lrD-00043v-4y; Thu, 04 Feb 2021 21:08:07 +0000 Subject: Re: [PATCH v4 09/10] userfaultfd: update documentation to describe minor fault handling To: Axel Rasmussen Cc: Alexander Viro , Alexey Dobriyan , Andrea Arcangeli , Andrew Morton , Anshuman Khandual , Catalin Marinas , Chinwen Chang , Huang Ying , Ingo Molnar , Jann Horn , Jerome Glisse , Lokesh Gidra , "Matthew Wilcox (Oracle)" , Michael Ellerman , =?UTF-8?Q?Michal_Koutn=c3=bd?= , Michel Lespinasse , Mike Kravetz , Mike Rapoport , Nicholas Piggin , Peter Xu , Shaohua Li , Shawn Anastasio , Steven Rostedt , Steven Price , Vlastimil Babka , LKML , linux-fsdevel@vger.kernel.org, Linux MM , Adam Ruprecht , Cannon Matthews , "Dr . David Alan Gilbert" , David Rientjes , Mina Almasry , Oliver Upton References: <20210204183433.1431202-1-axelrasmussen@google.com> <20210204183433.1431202-10-axelrasmussen@google.com> From: Randy Dunlap Message-ID: Date: Thu, 4 Feb 2021 13:07:55 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 2/4/21 1:04 PM, Axel Rasmussen wrote: > On Thu, Feb 4, 2021 at 11:57 AM Randy Dunlap wrote: >> >> Hi Axel- >> >> one typo found: >> >> On 2/4/21 10:34 AM, Axel Rasmussen wrote: >>> Reword / reorganize things a little bit into "lists", so new features / >>> modes / ioctls can sort of just be appended. >> >> Good plan. >> >>> >>> Signed-off-by: Axel Rasmussen >>> --- >>> Documentation/admin-guide/mm/userfaultfd.rst | 107 ++++++++++++------- >>> 1 file changed, 66 insertions(+), 41 deletions(-) >>> >>> diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst >>> index 65eefa66c0ba..cfd3daf59d0e 100644 >>> --- a/Documentation/admin-guide/mm/userfaultfd.rst >>> +++ b/Documentation/admin-guide/mm/userfaultfd.rst >> >> [snip] >> >>> - >>> -Once the ``userfaultfd`` has been enabled the ``UFFDIO_REGISTER`` ioctl should >>> -be invoked (if present in the returned ``uffdio_api.ioctls`` bitmask) to >>> -register a memory range in the ``userfaultfd`` by setting the >>> +events, except page fault notifications, may be generated: >>> + >>> +- The ``UFFD_FEATURE_EVENT_*`` flags indicate that various other events >>> + other than page faults are supported. These events are described in more >>> + detail below in the `Non-cooperative userfaultfd`_ section. >>> + >>> +- ``UFFD_FEATURE_MISSING_HUGETLBFS`` and ``UFFD_FEATURE_MISSING_SHMEM`` >>> + indicate that the kernel supports ``UFFDIO_REGISTER_MODE_MISSING`` >>> + registrations for hugetlbfs and shared memory (covering all shmem APIs, >>> + i.e. tmpfs, ``IPCSHM``, ``/dev/zero``, ``MAP_SHARED``, ``memfd_create``, >>> + etc) virtual memory areas, respectively. >>> + >>> +- ``UFFD_FEATURE_MINOR_HUGETLBFS`` indicates that the kernel supports >>> + ``UFFDIO_REGISTER_MODE_MINOR`` registration for hugetlbfs virtual memory >>> + areas. >>> + >>> +The userland application should set the feature flags it intends to use >> >> (ah, userspace has moved to userland temporarily. :) > > For better or worse, other parts of the document I'm not touching also > use this wording. Maybe we should s/userland/userspace/g, but perhaps > better done as a separate commit to keep this diff focused? > Anecdotally, the use of "userland" doesn't seem to be completely > unprecedented (e.g. grep -r "userland" | wc -l yields 566 matches in > the kernel tree). > > I don't have strong feelings, and I was amused by picturing some > Shire-esque countryside with a friendly sign that reads: ~userland > welcomes you~. :) I'm OK with not changing it. Up to you. -- ~Randy