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 X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=BAYES_00,DATE_IN_PAST_12_24, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71779C433E1 for ; Sat, 15 Aug 2020 22:12:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 400F320657 for ; Sat, 15 Aug 2020 22:12:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597529541; bh=FIMa12YBIxbmIJo5mkpIyQCNLan+KFvgEdkF5NlPF5Y=; h=Date:From:To:Subject:In-Reply-To:References:List-ID:From; b=cTlYlLmqe0xvXeK8ZJeY/ZiKrRCqiqE7791lFRgiZgrTx6QRQR0iQ1mtLxcWWQLYx Wl4+lI5M8XcWSBEI2fIfPgsMoNO4nXCm+ctADn9Zz5gsBjcTsOqiYDtK0Hn2NO2jPE sk4aHzGcbj6CjMjAcPrtR6l6kO0xJFhoeSf9CUh8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729252AbgHOWK2 (ORCPT ); Sat, 15 Aug 2020 18:10:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:41748 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728120AbgHOWKZ (ORCPT ); Sat, 15 Aug 2020 18:10:25 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9C37C22D2B; Sat, 15 Aug 2020 04:14:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597464899; bh=FIMa12YBIxbmIJo5mkpIyQCNLan+KFvgEdkF5NlPF5Y=; h=Date:From:To:Subject:In-Reply-To:References:From; b=VgsexbWCry2QnQXKmEDGliFphiT40hu4/JgjYaHoAmW9k5oOECFOwHdBDHdeQjAbZ vno4rCgEnXx+PinQDLJSUDb10OB+9Zz1BOkXyeHwdMO+7T7dGte/FY8LeG73BPju2Y tq0JWf7U2JplIyT+Fqkv/wADobAPrpVkUDyC9UjQ= Date: Fri, 14 Aug 2020 21:14:59 -0700 From: Andrew Morton To: Zhaoyang Huang , Roman Gushchin , Zhaoyang Huang , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm : sync ra->ra_pages with bdi->ra_pages Message-Id: <20200814211459.65f6db0211872e30684a630a@linux-foundation.org> In-Reply-To: <20200814131034.f71a91c6827904e12a629e04@linux-foundation.org> References: <1597395824-3325-1-git-send-email-zhaoyang.huang@unisoc.com> <20200814131034.f71a91c6827904e12a629e04@linux-foundation.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 Aug 2020 13:10:34 -0700 Andrew Morton wrote: > On Fri, 14 Aug 2020 17:03:44 +0800 Zhaoyang Huang wrote: > > > Some system(like android) will turbo read during startup via expanding the > > readahead window and then set it back to normal(128kb as usual). However, some > > files in the system process context will keep to be opened since it is opened > > up and has no chance to sync with the updated value as it is almost impossible > > to change the files attached to the inode(processes are unaware of these things) > > How about making VM_READAHEAD_PAGES a variable? Or make it settable in Kconfig?