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 3F764C433F5 for ; Sat, 22 Jan 2022 03:38:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 64BB96B0080; Fri, 21 Jan 2022 22:38:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5FB486B0083; Fri, 21 Jan 2022 22:38:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4C3E66B0085; Fri, 21 Jan 2022 22:38:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0023.hostedemail.com [216.40.44.23]) by kanga.kvack.org (Postfix) with ESMTP id 3948D6B0080 for ; Fri, 21 Jan 2022 22:38:09 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id D908E98C2A for ; Sat, 22 Jan 2022 03:38:08 +0000 (UTC) X-FDA: 79056514656.11.703293E Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf31.hostedemail.com (Postfix) with ESMTP id CC0B52000E for ; Sat, 22 Jan 2022 03:38:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=isIBTVsbnY0YR1Hkp92U+P4zi+XpFnHNGT0viRKHgoM=; b=ccKWQZ6hZ3WawGbvA0hGzH0jS2 g5hOl2KZ8PUgvE898zYzuEAL/DOAy//YF6HcthkOOuibrRXePDzvD9QkmmknFWLiq2ha3OARL5mQl mtaf6o1JikOiIG/xhXvvPfd+/KykwXo+uFX37jLKxu3Tu93bpsZpeS+fgGkWdrjQjKjxBaFqm9ANQ o0Xqm0JjhYDZ/Czlc31jYpJL0EQvtz4HE/YzeCLlvRWkPdagQQdAcsKNuh9fEfmxDaS1JVEr47bqk 9oPVGLW7QtwR2S2ufRVZxmRaDketS8ztJcrUoTpIBffnQXO1c/S/HbDHHwjDPNyEM3a0r+mGeTcO6 gCqoG0vw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nB5PH-00G3f5-4m; Sat, 22 Jan 2022 01:41:31 +0000 Date: Sat, 22 Jan 2022 01:41:31 +0000 From: Matthew Wilcox To: "Longpeng (Mike, Cloud Infrastructure Service Product Dept.)" Cc: Khalid Aziz , Barry Song <21cnbao@gmail.com>, Andrew Morton , Arnd Bergmann , Dave Hansen , David Hildenbrand , LKML , Linux-MM , Mike Rapoport , Suren Baghdasaryan Subject: Re: [RFC PATCH 0/6] Add support for shared PTEs across processes Message-ID: References: <20220121010806.5607-1-21cnbao@gmail.com> <0ec88ae7-9740-835d-1f07-60bd57081fcd@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: CC0B52000E X-Stat-Signature: hxbd41b7u6mesggtax5ehixqfuduoebm Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=ccKWQZ6h; spf=none (imf31.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspamd-Server: rspam01 X-HE-Tag: 1642822687-13228 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 Sat, Jan 22, 2022 at 01:39:46AM +0000, Longpeng (Mike, Cloud Infrastructure Service Product Dept.) wrote: > > > Our use case is that we have some very large files stored on persistent > > > memory which we want to mmap in thousands of processes. So the first > > The memory overhead of PTEs would be significantly saved if we use > hugetlbfs in this case, but why not? Because we want the files to be persistent across reboots.