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=-4.0 required=3.0 tests=BAYES_00,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 711D7C433E1 for ; Sat, 15 Aug 2020 04:15:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E36B222D72 for ; Sat, 15 Aug 2020 04:15:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="VgsexbWC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E36B222D72 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 434FA6B000D; Sat, 15 Aug 2020 00:15:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3E65E6B000E; Sat, 15 Aug 2020 00:15:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2D6B86B0010; Sat, 15 Aug 2020 00:15:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0097.hostedemail.com [216.40.44.97]) by kanga.kvack.org (Postfix) with ESMTP id 1AC646B000D for ; Sat, 15 Aug 2020 00:15:02 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id BCF46181AEF1E for ; Sat, 15 Aug 2020 04:15:01 +0000 (UTC) X-FDA: 77151487602.26.toes65_4004ef827002 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id 752321804B668 for ; Sat, 15 Aug 2020 04:15:01 +0000 (UTC) X-HE-Tag: toes65_4004ef827002 X-Filterd-Recvd-Size: 2336 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Sat, 15 Aug 2020 04:15:00 +0000 (UTC) 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 X-Rspamd-Queue-Id: 752321804B668 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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, 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?