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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E287FC433EF for ; Tue, 12 Apr 2022 20:42:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3F7626B0072; Tue, 12 Apr 2022 16:42:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3A7696B0073; Tue, 12 Apr 2022 16:42:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 26F036B0074; Tue, 12 Apr 2022 16:42:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0079.hostedemail.com [216.40.44.79]) by kanga.kvack.org (Postfix) with ESMTP id 104AB6B0072 for ; Tue, 12 Apr 2022 16:42:05 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id C4BAE183D71E0 for ; Tue, 12 Apr 2022 20:42:04 +0000 (UTC) X-FDA: 79349398968.25.AAED4B7 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf31.hostedemail.com (Postfix) with ESMTP id 5C90520006 for ; Tue, 12 Apr 2022 20:42:04 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 29565B82030; Tue, 12 Apr 2022 20:42:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46C9AC385A5; Tue, 12 Apr 2022 20:42:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1649796121; bh=lMFB0InmoR4pDJv6lAsrdPu5Trt63wkiB+MRAm1baLo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=1dZDrF9L+F538gzNAjJz9VyO3gg4x+HiTdod5RYW0DmIWGmmunI4/OgjJyFcm9C3I eJeWQ+/r6DqlPyOi1XCg/kgPfZKRZAjNk41oTc+2jGsl4+x6/TMWkU59/I8DEOa5Nn v5RyIjcRhuMBFVO+EDJbPo65siomjZMUDj/79JTc= Date: Tue, 12 Apr 2022 13:41:59 -0700 From: Andrew Morton To: Axel Rasmussen Cc: Alexander Viro , "Dmitry V . Levin" , Gleb Fotengauer-Malinovskiy , Mike Kravetz , Nadav Amit , Peter Xu , Shuah Khan , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH 2/2] userfaultfd: selftests: modify selftest to use /dev/userfaultfd Message-Id: <20220412134159.f0a1d0d77f5b01638007bf4b@linux-foundation.org> In-Reply-To: <20220412202942.386981-2-axelrasmussen@google.com> References: <20220412202942.386981-1-axelrasmussen@google.com> <20220412202942.386981-2-axelrasmussen@google.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=1dZDrF9L; spf=pass (imf31.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Stat-Signature: bajxogpe3hp3cngysbza87t6666sqtpq X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 5C90520006 X-HE-Tag: 1649796124-541726 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 Tue, 12 Apr 2022 13:29:42 -0700 Axel Rasmussen wrote: > Prefer this new interface, but if using it fails for any reason just > fall back to using userfaultfd(2) as before. This seems a poor idea - the old interface will henceforth be untested. Why not tweak the code to test both interfaces?