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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9BD77C433FE for ; Tue, 25 Jan 2022 18:57:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230331AbiAYS50 (ORCPT ); Tue, 25 Jan 2022 13:57:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43222 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233867AbiAYS4i (ORCPT ); Tue, 25 Jan 2022 13:56:38 -0500 Received: from mail-lj1-x22a.google.com (mail-lj1-x22a.google.com [IPv6:2a00:1450:4864:20::22a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98798C06173B for ; Tue, 25 Jan 2022 10:56:34 -0800 (PST) Received: by mail-lj1-x22a.google.com with SMTP id c15so12439484ljf.11 for ; Tue, 25 Jan 2022 10:56:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=fTIC0KYcAU7y+7wUnGRMhkBW/04VGMWDeVkUkSJAGmQ=; b=uawUMPNcPHv5iyPo4LsdD2z5I1KWjd80mTQkfdi//xbsOLnUlx37kKYhxJQ36Ugdtv qTwb9l8FSud2YC9Rqhe1fgqVPtyKMrzh8AKP57x+/Y9FP+KjtdFESmnvaWarog81y0Nu 6RMAqUDIiwZvsVpks0rr1orKwCgm6grx5NYKG4OtsL3ijkniCzLjXTKvkkQv6IgiMXrb peOfUymNCHOENVp77E7Cq8Ou+TSDA756j5mkZBpNlxGJ9xNmmvZaSFCpc96OCnp20KLf LKTa+X5ze94gjndZXK1u9CC5l1rkhiBxnpZsByIgo/6ptgdlhYLMKYlOpOhIharThM1+ JLEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=fTIC0KYcAU7y+7wUnGRMhkBW/04VGMWDeVkUkSJAGmQ=; b=2H2cMAAtll5uLxNTgAYAGgqqnmlBHP0ZjFkLss3yJ0moEr/bEMYk3eI8d1VbGHLR/k dMJpJ1/lLavEXpGqt0acdO5mjZ8hUtkNcP6Sf8ORfpfsu25lmDxHfj0ClU/7K5duiZjh 6n4GVu5mM2Ccgw5th7SHXjT3geuhssLec7OJOUjrXkkwPqAIDiz1xtbP4AtnRsBqwOEm iamOfJLfdf7/ogyX47nZWAA4Fh0C1GIT4CzVGY9qcYUpGvI6/UwWKcedfLMTuTLVxHdk pEKYjMKDPuwMKFZd62TvoBGr5Bdaj7/igR5FMhe25iVRHRDsBDpn9eY1G9qYPbUc4MAt xd5w== X-Gm-Message-State: AOAM532xyc5s05Z4hDOZH2xVSZnydkPn9iP/DGYgBwUytAQ9QYgYLrrt OE9cVSZoLOrzqJQCAGt8xlbNgQ== X-Google-Smtp-Source: ABdhPJw8URkiYeFKqQFgbfsxeh5R2XmdcNoDAY7XJpAG5VI3oM9BQ2Z5+KLqSd/PqRHV/HXOzV6XDQ== X-Received: by 2002:a2e:b744:: with SMTP id k4mr3107981ljo.351.1643136993000; Tue, 25 Jan 2022 10:56:33 -0800 (PST) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id y11sm1228113ljj.69.2022.01.25.10.56.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Jan 2022 10:56:32 -0800 (PST) Received: by box.localdomain (Postfix, from userid 1000) id 65C4E103C0E; Tue, 25 Jan 2022 21:57:05 +0300 (+03) Date: Tue, 25 Jan 2022 21:57:05 +0300 From: "Kirill A. Shutemov" To: Matthew Wilcox Cc: Khalid Aziz , akpm@linux-foundation.org, longpeng2@huawei.com, arnd@arndb.de, dave.hansen@linux.intel.com, david@redhat.com, rppt@kernel.org, surenb@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH 0/6] Add support for shared PTEs across processes Message-ID: <20220125185705.wf7p2l77vggipfry@box.shutemov.name> References: <20220125114212.ks2qtncaahi6foan@box.shutemov.name> <20220125135917.ezi6itozrchsdcxg@box.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 25, 2022 at 02:09:47PM +0000, Matthew Wilcox wrote: > > I think zero-API approach (plus madvise() hints to tweak it) is worth > > considering. > > I think the zero-API approach actually misses out on a lot of > possibilities that the mshare() approach offers. For example, mshare() > allows you to mmap() many small files in the shared region -- you > can't do that with zeroAPI. Do you consider a use-case for many small files to be common? I would think that the main consumer of the feature to be mmap of huge files. And in this case zero enabling burden on userspace side sounds like a sweet deal. -- Kirill A. Shutemov