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 6C18EECAAA6 for ; Fri, 26 Aug 2022 18:03:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F2F45940007; Fri, 26 Aug 2022 14:03:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EB7916B0074; Fri, 26 Aug 2022 14:03:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D5920940007; Fri, 26 Aug 2022 14:03:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id C4BFA6B0073 for ; Fri, 26 Aug 2022 14:03:03 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 98FE0AB0E4 for ; Fri, 26 Aug 2022 18:03:03 +0000 (UTC) X-FDA: 79842515046.29.A6A0647 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf25.hostedemail.com (Postfix) with ESMTP id 5A05AA0024 for ; Fri, 26 Aug 2022 18:03:01 +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=QNVtuCWM82Mnt2qBfsTXNsVwkbP1OFAoF7adgDvkMvE=; b=a8EFiyswlmdn8tI9eMyIiDefqy OwMPVJSZcIENgsMyfHMpV9wFIgTcfLteXFMUIhquTqSDKY7zsnY+OUyaOF3mvBC24usFyNHWp4RSa 5ZVr+gCTf/MpCXY107ITh2tI9mijeCB8eiVgBFujdGE7e0LQxLhdrJtcGjz1TaewBIhIcDVaM0NbE 9P4R3c34OPQmR++8sUIQM/gd/n7yhh5kG1TudH+HoerNaNcFeJdLtBZvRQuStCmRUeNjCMRu/ng+v L+bmpdueX34QufaR6sZPMVjDhXmMLnv1yu2qWEanBEGVsiTvz7M3lASOaxUUAvry3a9TxLrCSTTwN Ui3E9Z/Q==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1oRdfM-000k9m-Q9; Fri, 26 Aug 2022 18:02:48 +0000 Date: Fri, 26 Aug 2022 19:02:48 +0100 From: Matthew Wilcox To: Minchan Kim Cc: Yu Zhao , "Yin, Fengwei" , Yang Shi , Andrew Morton , Linux-MM , =?utf-8?B?6Z+p5aSp56GV?= , mawupeng Subject: Re: (resend)WARNING: trying to isolate tail page in isolate_lru_page Message-ID: References: <485f8c33.2471b.182d5726afb.Coremail.hantianshuo@iie.ac.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1661536983; a=rsa-sha256; cv=none; b=cjlrCOMLZugYT9ML7DTBrGpoxiRMteix+L9hC4Cr6KZVnQcWFY/cTqHoQTsJDF/DlEfQJe 3q7H/xi7a798puuSw/liRQexmkYc0VwZ3ZmusT3cYIrPrcCVWWtKUaUZwLx1ujTl7PJBGG pYvBISvqsIKXc8UA7Mrl1yRC20CkrOI= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=a8EFiysw; dmarc=none; spf=none (imf25.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1661536983; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=QNVtuCWM82Mnt2qBfsTXNsVwkbP1OFAoF7adgDvkMvE=; b=D1qOw2KNxcwJW37QnmGIffmoD1O4iHKbXbeiBQZ26KRizNz2/35EoA4cXzdMdb3DizmZgH PUJf8xDElHg7hxeU0uDhyonT7D4uQgtnyyjTUUdmX+oBEbkrCZXnsFVehdhladMzDxjxRW WGY1xEXaVLgXwUImNG4DKn4iIMLdWSA= Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=a8EFiysw; dmarc=none; spf=none (imf25.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: u84nm51p36m57nucw1edig5e4f4ech4i X-Rspamd-Queue-Id: 5A05AA0024 X-HE-Tag: 1661536981-948456 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 Fri, Aug 26, 2022 at 10:53:46AM -0700, Minchan Kim wrote: > Long term, that's better idea(For stable backport, I'd like to go with > simple PageLRU check). > > I wonder it's possible to mix LRU pages and non-struct pages together > in a VMA. Otherwise, could we reuse(abuse) VM_MIXEDMAP? On a bit of a tangent, I'm not sure that we should be allowing this for file pages at all. I see that we only allow it if mapcount is 1, but page cache is also used by applications that don't mmap it. So if some other application is using /tmp/bigfile with read() and write(), I can force that memory out of the page cache by mmaping it and calling MADV_PAGEOUT. That could be used as an exfiltration side-channel, for example.