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 1FBD0C43334 for ; Sat, 2 Jul 2022 04:24:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8E72E6B0073; Sat, 2 Jul 2022 00:24:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8949F6B0074; Sat, 2 Jul 2022 00:24:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7855B6B0075; Sat, 2 Jul 2022 00:24:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 68F956B0073 for ; Sat, 2 Jul 2022 00:24:07 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 3612734D23 for ; Sat, 2 Jul 2022 04:24:07 +0000 (UTC) X-FDA: 79640867334.07.5F28F11 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf19.hostedemail.com (Postfix) with ESMTP id 93CAF1A0039 for ; Sat, 2 Jul 2022 04:24:06 +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 dfw.source.kernel.org (Postfix) with ESMTPS id 656FC60C4A; Sat, 2 Jul 2022 04:24:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF9A0C341C7; Sat, 2 Jul 2022 04:24:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1656735844; bh=0JxhHAplfI63oB/NzCnRqg7Nzu+/8/KjAvBoeKJIaJY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=X2UjaxB7lVcvMqDmSNFUBUuvl8wh3eEfB1LTc9Z9xTkwQMSqHY4js3IBGTpNNcYoL m1/60T5cdPbZRoW8JkGhbbeo5i8clmn65j1+qMCZnq1sIpDs3dXCKVdFNZhgorIDpq etEsUljuPoIoFHxAE7ZaLMsjLcLQ68CbmcnPajL8= Date: Fri, 1 Jul 2022 21:24:03 -0700 From: Andrew Morton To: Khalid Aziz Cc: willy@infradead.org, aneesh.kumar@linux.ibm.com, arnd@arndb.de, 21cnbao@gmail.com, corbet@lwn.net, dave.hansen@linux.intel.com, david@redhat.com, ebiederm@xmission.com, hagen@jauu.net, jack@suse.cz, keescook@chromium.org, kirill@shutemov.name, kucharsk@gmail.com, linkinjeon@kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, longpeng2@huawei.com, luto@kernel.org, markhemm@googlemail.com, pcc@google.com, rppt@kernel.org, sieberf@amazon.com, sjpark@amazon.de, surenb@google.com, tst@schoebel-theuer.de, yzaikin@google.com Subject: Re: [PATCH v2 0/9] Add support for shared PTEs across processes Message-Id: <20220701212403.77ab8139b6e1aca87fae119e@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656735846; a=rsa-sha256; cv=none; b=kP1A7oa5D7N33aHYKYR/k7E+DWmSUYRXhyDJo3sKr0Q40XA/H6UM0tht2AKahnIOAnKhoU 8YogndYbzAYr6djyZVuoJdAMG9/OA7XMo6FWF1aO1i4hu+f8+yjTg7QJ2FVIGjj9UczmWd 4t9uYMQFzG1/5jlkGtcZUzaiWQZmayA= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=X2UjaxB7; dmarc=none; spf=pass (imf19.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656735846; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=hMjp5YAKv4ZfrQGB8O/jy8Tf2BA4d2mEzIAlY0ouDs0=; b=Fq4JiBLTSTypfDxXyo3RQyQ7nJBc4iYXaeT7HU4XmwdW2oOEcPVoTcR3rLecSVc9mLT2Lx mXizJzg2bx8a+hYrXSMdcAPzl3fI2fSzlW9tF7GiAXodrREBLz2cdvbgorapANtSSnmrSc wW+lV5N2lcDL5kw50FbPnHtujjk9KXo= Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=X2UjaxB7; dmarc=none; spf=pass (imf19.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 93CAF1A0039 X-Stat-Signature: sd9xeejgd1zpimwo15mwr5p8yagc45ck X-Rspam-User: X-HE-Tag: 1656735846-740494 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 Wed, 29 Jun 2022 16:53:51 -0600 Khalid Aziz wrote: > This patch series implements a mechanism in kernel to allow > userspace processes to opt into sharing PTEs. It adds a new > in-memory filesystem - msharefs. Dumb question: why do we need a new filesystem for this? Is it not feasible to permit PTE sharing for mmaps of tmpfs/xfs/ext4/etc files?