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 56B38C43334 for ; Sat, 25 Jun 2022 09:19:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 899818E0294; Sat, 25 Jun 2022 05:19:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7F9CE8E028E; Sat, 25 Jun 2022 05:19:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6990C8E0294; Sat, 25 Jun 2022 05:19:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 574F78E028E for ; Sat, 25 Jun 2022 05:19:53 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 219C634858 for ; Sat, 25 Jun 2022 09:19:53 +0000 (UTC) X-FDA: 79616211066.08.D048D3A Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf16.hostedemail.com (Postfix) with ESMTP id 8C99D180025 for ; Sat, 25 Jun 2022 09:19:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=obSv7fC50QS9GVguFIU1ed1kozCQr6nKrlMvCioHMhs=; b=UG0+S5zMfvO+mGEodQCPyJAYTw i9B451JBonTi4ydY0c4ycO8AD30aaMzCR75Ny43eUPt21Nw2cWgMg+AAD2x8RM4kbxrWEBpPWo8nd hus9/E9IYxy55q9ZVa9nJ1mnI5Q5FE5qRQARlTkoajCr+n1rKSFCDByA9RYCWZ8Phjj3+LlPLfeJ9 EFnsEEQm1DSs55HJWBwrTtsn45l2zjBSJKt1vYP8xkwcpu7oHcqrAMZLwVdTJaqd6xs9hMd1xihyE uQBI5TA4QwULMxfaEDUi+N3t7RviU3EMVsmoJaoLc7diL56E9UV7/QWVRSVIK+X/ZIL2OFSnd/En8 csEgKUvw==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1o51xA-005J9l-3G; Sat, 25 Jun 2022 09:19:44 +0000 Date: Sat, 25 Jun 2022 02:19:44 -0700 From: Christoph Hellwig To: cgel.zte@gmail.com Cc: viro@zeniv.linux.org.uk, hughd@google.com, ran.xiaokai@zte.com.cn, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] drop caches: skip tmpfs and ramfs Message-ID: References: <20220624182121.995294-1-ran.xiaokai@zte.com.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220624182121.995294-1-ran.xiaokai@zte.com.cn> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656148792; a=rsa-sha256; cv=none; b=K4Gne2VsbGR/GptcF7F93zlwqM5V8NmBj832EfQ0JIBWGoKLMWOVpMxeT0mIH5gOd/FX+W pyw81ntnS9UV5S8FPt1d8nrqWzW2aSZvt8FaJUf83AwYPP/GoaSUx3E1yhVnaErWleL6EH JCoSkPLOOAJTp4VZjeDxOQBg2/iev0s= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=UG0+S5zM; dmarc=none; spf=none (imf16.hostedemail.com: domain of BATV+b4253a7024c3f5cecdb3+6880+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+b4253a7024c3f5cecdb3+6880+infradead.org+hch@bombadil.srs.infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656148792; 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=obSv7fC50QS9GVguFIU1ed1kozCQr6nKrlMvCioHMhs=; b=hty2gX0vATBVwYHilSpBNZPMoErmursEhniZpZ6Ebf7Tu+f194ujSDHc+rvEo3ZdW6//Rk cmsU7GaNJXTBbbY8EyYKs8gIJ07sJuaqJ6J85zy+yrMpdqRljjvrSWQhNmq4j52OiNm8aK S//b25vY2i7qRlU19xPnN5EqzGgeKwc= X-Stat-Signature: ncbmcsmkrpatk4z643qm7myaaiwkxt3f X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 8C99D180025 Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=UG0+S5zM; dmarc=none; spf=none (imf16.hostedemail.com: domain of BATV+b4253a7024c3f5cecdb3+6880+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+b4253a7024c3f5cecdb3+6880+infradead.org+hch@bombadil.srs.infradead.org X-HE-Tag: 1656148791-406398 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, Jun 24, 2022 at 06:21:21PM +0000, cgel.zte@gmail.com wrote: > From: Ran Xiaokai > > All tmpfs and ramfs pages have PG_dirty bit set > once they are allocated and added to the pagecache。So pages > can not be freed from tmpfs or ramfs. So skip tmpfs and ramfs > when drop caches. Hard coding magic constants in VFS code is a bad idea. If you have numbers to justify this change (which should go into this commit log), it can be properly solved by a flag on the super block, file_system_type or even better bdi.