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=-8.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 CC634C432C0 for ; Mon, 2 Dec 2019 22:21:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9AB2B2073C for ; Mon, 2 Dec 2019 22:21:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="FKeTDSTe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726138AbfLBWVz (ORCPT ); Mon, 2 Dec 2019 17:21:55 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:56282 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725834AbfLBWVz (ORCPT ); Mon, 2 Dec 2019 17:21:55 -0500 Received: by mail-wm1-f65.google.com with SMTP id a131so973985wme.5 for ; Mon, 02 Dec 2019 14:21:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-disposition:in-reply-to:user-agent; bh=czs8sdBA/sHPCWDkIWdbqK/qXxxuF+2nb4aU5nz/4aQ=; b=FKeTDSTeK4Ops62th+i3KGYu31KHBGHSCR1EpkNSQHfRaBR3H/1WzSwTz0oRbnlSWo YPVoCjaFhdS/gHmLGhCqhrwgQUfJCs1cgAm1Qd9TKszJyGJ51dSZgsN8ku49i4eDYxzd ZneeTAhJfdMqOP7lKkB1KoZs8u5A/eldm/fD6MyZkaJt+O88xttwq9wqq8jBdHk0M1n+ 10ylITCIMtaN7d3k7pJN+sNYdQ46/SR3I2S3uEumUsGy56j1ays13gIIgaZIdZMI/vIJ T7cuJC/qo/HOKj6xFMqJxaKei/p5Dxc+rKmGAd4E4qmxHSios96WQGDeBEHHTxwZA0mx T6mA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:reply-to :references:mime-version:content-disposition:in-reply-to:user-agent; bh=czs8sdBA/sHPCWDkIWdbqK/qXxxuF+2nb4aU5nz/4aQ=; b=aF/zX1WAEGA06ignk7NPVygsNHuI476BGdjdY9xkZqvGMlnIWGzC2Ons7/oZcSs6pE 26CnPPmETCOf8kYIgJM+9L19UswBykCnO1itopRoBeDJwL7DFemvHFT62jgZ1TRTNPi2 ehMgPOklaLvXBh1fEo5oWmB6oXI+nWIdf+33V0wc+7ezHpK2fBZN2krAQpgytXGDIsuO k12Q/gmVwpwUym0xt0sXV1ecKjyHSZuwtkg41gGgsDkcXQri5xO53Q31U94TkTSHR4vt XqV7UN/Qtv5VgAxixGpPntvvTQunxgIxHeiH4NvwL67VcXjWm0ltsZlyEUj6r7fF/X2s +59A== X-Gm-Message-State: APjAAAVz2/QF60l7ZhxfGAoBe8nCZq0CkhlfkjAe5cGY8Rsh7+iMBkf7 R8bCIGAhBjyQUmfSSzxE5Js= X-Google-Smtp-Source: APXvYqxnIkZmublYgiMmgRlGkKyyjNYgFaG8tIcog+gMgExU1kHo5gu5Ex090bDuXJbn1Ong+gHcNA== X-Received: by 2002:a1c:1dc9:: with SMTP id d192mr23483147wmd.92.1575325312929; Mon, 02 Dec 2019 14:21:52 -0800 (PST) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id b63sm760833wmb.40.2019.12.02.14.21.51 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 02 Dec 2019 14:21:52 -0800 (PST) Date: Mon, 2 Dec 2019 22:21:51 +0000 From: Wei Yang To: "Kirill A. Shutemov" Cc: Wei Yang , Wei Yang , akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] mm/page_vma_mapped: use PMD_SIZE instead of calculating it Message-ID: <20191202222151.xx4g3ry7mrcselh5@master> Reply-To: Wei Yang References: <20191128010321.21730-1-richardw.yang@linux.intel.com> <20191128083255.ab5rwj7gvktwunik@box.shutemov.name> <20191128212226.sfrhfs5m3q7m6tly@master> <20191202080315.oqtm3q7cyfkl5rma@box.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191202080315.oqtm3q7cyfkl5rma@box.shutemov.name> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 02, 2019 at 11:03:15AM +0300, Kirill A. Shutemov wrote: >On Thu, Nov 28, 2019 at 09:22:26PM +0000, Wei Yang wrote: >> On Thu, Nov 28, 2019 at 11:32:55AM +0300, Kirill A. Shutemov wrote: >> >On Thu, Nov 28, 2019 at 09:03:20AM +0800, Wei Yang wrote: >> >> At this point, we are sure page is PageTransHuge, which means >> >> hpage_nr_pages is HPAGE_PMD_NR. >> >> >> >> This is safe to use PMD_SIZE instead of calculating it. >> >> >> >> Signed-off-by: Wei Yang >> >> --- >> >> mm/page_vma_mapped.c | 2 +- >> >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> >> >> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c >> >> index eff4b4520c8d..76e03650a3ab 100644 >> >> --- a/mm/page_vma_mapped.c >> >> +++ b/mm/page_vma_mapped.c >> >> @@ -223,7 +223,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) >> >> if (pvmw->address >= pvmw->vma->vm_end || >> >> pvmw->address >= >> >> __vma_address(pvmw->page, pvmw->vma) + >> >> - hpage_nr_pages(pvmw->page) * PAGE_SIZE) >> >> + PMD_SIZE) >> >> return not_found(pvmw); >> >> /* Did we cross page table boundary? */ >> >> if (pvmw->address % PMD_SIZE == 0) { >> > >> >It is dubious cleanup. Maybe page_size(pvmw->page) instead? It will not >> >break if we ever get PUD THP pages. >> > >> >> Thanks for your comment. >> >> I took a look into the code again and found I may miss something. >> >> I found we support PUD THP pages, whilc hpage_nr_pages() just return >> HPAGE_PMD_NR on PageTransHuge. Why this is not possible to return PUD number? > >We only support PUD THP for DAX. Means, we don't have struct page for it. > BTW, may I ask why you suggest to use page_size() if we are sure only PMD THP page is used here? To be more generic? >-- > Kirill A. Shutemov -- Wei Yang Help you, Help me