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=-11.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 2BD35C433E2 for ; Wed, 2 Sep 2020 20:30:01 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DB4D320678 for ; Wed, 2 Sep 2020 20:30:00 +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="lGgdPmra" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB4D320678 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 85449900022; Wed, 2 Sep 2020 16:30:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8049E90000F; Wed, 2 Sep 2020 16:30:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6F30F900022; Wed, 2 Sep 2020 16:30:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0199.hostedemail.com [216.40.44.199]) by kanga.kvack.org (Postfix) with ESMTP id 5AA2990000F for ; Wed, 2 Sep 2020 16:30:00 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 18F1F362A for ; Wed, 2 Sep 2020 20:30:00 +0000 (UTC) X-FDA: 77219262960.11.art36_3a08a6e270a3 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin11.hostedemail.com (Postfix) with ESMTP id E1FBB180F8B82 for ; Wed, 2 Sep 2020 20:29:59 +0000 (UTC) X-HE-Tag: art36_3a08a6e270a3 X-Filterd-Recvd-Size: 3775 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Wed, 2 Sep 2020 20:29:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To:Subject:Sender :Reply-To:Content-ID:Content-Description; bh=NZgrNRwvUqZ2fItnpuN0y7CKknqhb7o5yUK6eUEHgO8=; b=lGgdPmracBAkg8LSxWNuCfHRRv bNQ0bBliMublqsUgS+ZD/b2sjBi2dwYvGKicxbxrOcTIgxGmQFBBvIhrM+Yq1D54X2MrPgMaMQcMW D/sj1l4tjaI/iteMTNUy4+pBfszZe/nqpV4kHMBmatuRkocTg1z8JWi0a6Z0Ka4PcU3eknsPSK2xe dQ7KYz6xlAzQ6e0bpUUvurDQiwM9DhAT8tk2JCb02y/8WkA3RxASKjbs1JpZm7SXKh0krLULQOUSe mZQ02Me9obB2ruDt74ooLU4W4MqLSbFyZdYIKsGyCwtssmI3Zo58VDM7u8bMItDJmM+2XsyCDxgHV Z6Q/ZNYw==; Received: from [2601:1c0:6280:3f0::19c2] by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDZNx-000637-37; Wed, 02 Sep 2020 20:29:37 +0000 Subject: Re: [RFC PATCH 01/16] mm: add pagechain container for storing multiple pages. To: Zi Yan , linux-mm@kvack.org, Roman Gushchin Cc: Rik van Riel , "Kirill A . Shutemov" , Matthew Wilcox , Shakeel Butt , Yang Shi , David Nellans , linux-kernel@vger.kernel.org References: <20200902180628.4052244-1-zi.yan@sent.com> <20200902180628.4052244-2-zi.yan@sent.com> From: Randy Dunlap Message-ID: <5a91ac07-2c15-2e15-caec-5570bacf415b@infradead.org> Date: Wed, 2 Sep 2020 13:29:33 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200902180628.4052244-2-zi.yan@sent.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E1FBB180F8B82 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 9/2/20 11:06 AM, Zi Yan wrote: > From: Zi Yan > > When depositing page table pages for 1GB THPs, we need 512 PTE pages + > 1 PMD page. Instead of counting and depositing 513 pages, we can use the > PMD page as a leader page and chain the rest 512 PTE pages with ->lru. > This, however, prevents us depositing PMD pages with ->lru, which is > currently used by depositing PTE pages for 2MB THPs. So add a new > pagechain container for PMD pages. > > Signed-off-by: Zi Yan > --- > include/linux/pagechain.h | 73 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 73 insertions(+) > create mode 100644 include/linux/pagechain.h > > diff --git a/include/linux/pagechain.h b/include/linux/pagechain.h > new file mode 100644 > index 000000000000..be536142b413 > --- /dev/null > +++ b/include/linux/pagechain.h > @@ -0,0 +1,73 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * include/linux/pagechain.h > + * > + * In many places it is efficient to batch an operation up against multiple > + * pages. A pagechain is a multipage container which is used for that. > + */ > + > +#ifndef _LINUX_PAGECHAIN_H > +#define _LINUX_PAGECHAIN_H > + > +#include > + > +/* 14 pointers + two long's align the pagechain structure to a power of two */ > +#define PAGECHAIN_SIZE 13 OK, I'll bite. I see neither 14 pointers nor 2 longs below. Is the comment out of date or am I just confuzed? Update: struct list_head is 2 pointers, so I see 15 pointers & one unsigned int. Where are the 2 longs? > + > +struct page; > + > +struct pagechain { > + struct list_head list; > + unsigned int nr; > + struct page *pages[PAGECHAIN_SIZE]; > +}; thanks. -- ~Randy