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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 C5418C433E0 for ; Wed, 3 Jun 2020 21:51:34 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 628DD20734 for ; Wed, 3 Jun 2020 21:51:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="eYh60STY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 628DD20734 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9B6D480007; Wed, 3 Jun 2020 17:51:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9666B8E0006; Wed, 3 Jun 2020 17:51:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 87CC780007; Wed, 3 Jun 2020 17:51:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0049.hostedemail.com [216.40.44.49]) by kanga.kvack.org (Postfix) with ESMTP id 6C3A38E0006 for ; Wed, 3 Jun 2020 17:51:33 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 272D1181AEF10 for ; Wed, 3 Jun 2020 21:51:33 +0000 (UTC) X-FDA: 76889247666.03.offer41_d79ba43ca908 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin03.hostedemail.com (Postfix) with ESMTP id 0837128A4E8 for ; Wed, 3 Jun 2020 21:51:33 +0000 (UTC) X-HE-Tag: offer41_d79ba43ca908 X-Filterd-Recvd-Size: 2568 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf17.hostedemail.com (Postfix) with ESMTP for ; Wed, 3 Jun 2020 21:51:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=WFKjpmFPNO5zukj90rjGUlaZxkKudJBdthF2cSc+KfU=; b=eYh60STYrQxzv5V5oc2CXmvnzV eA/klZU0qTEOtdIvyxcym3o2couFDr7Xv6qIbf1VHAEFgEItJw0Of3iXeWkUkUSZIeuBBvadeMM3n Tqur5pMfe+/EDZQtY8wJi/zaKPDJDp6g+Li6zPr7Hlb8qeNabAVKTmQwC2e+IiRkEuoDyC7iNDMat bZJP2OQ+05fWiJpsxGU+j6nvSuZwxbj4svujd62PaYpL5NRIwkVx2ssqAqzw3JERk/sWosBaDoZM9 oSBVE5zI8zcFar2wnnYSPmEse/rTTszSr699hxWnpnv22xTeuDSVkJbwBQh7fFopv3144yHRMEkyg B59DqiKA==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jgbIB-0002Iy-1G; Wed, 03 Jun 2020 21:51:23 +0000 Date: Wed, 3 Jun 2020 14:51:22 -0700 From: Matthew Wilcox To: Hugh Dickins Cc: Johannes Weiner , Andrew Morton , Song Liu , "Kirill A. Shutemov" , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm,thp: stop leaking unreleased file pages Message-ID: <20200603215122.GR19604@bombadil.infradead.org> References: <20200526160140.GC850116@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 0837128A4E8 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 Wed, May 27, 2020 at 02:28:10PM -0700, Hugh Dickins wrote: > Saying "source inspection" reminds me: there is another funny in there, > but I don't think it matters very much in practice, and might need > rather a lot of testing to justify any particular patch: where > page_cache_sync_readahead() asks for PAGE_SIZE pages! > > "end - index" seems a more reasonable number to me: but then we > might find that reading ahead into the next huge extent had actually > been a useful optimization (and those readahead functions impose > their own caps, so PAGE_SIZE shouldn't work out too outrageously). That readahead was only added in 99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0 so it probably hasn't really been performance tested yet.