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=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 3CC0FC43215 for ; Tue, 3 Dec 2019 09:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 142F5206EC for ; Tue, 3 Dec 2019 09:47:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=shutemov-name.20150623.gappssmtp.com header.i=@shutemov-name.20150623.gappssmtp.com header.b="Y949QJfu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726114AbfLCJre (ORCPT ); Tue, 3 Dec 2019 04:47:34 -0500 Received: from mail-lf1-f68.google.com ([209.85.167.68]:36325 "EHLO mail-lf1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725773AbfLCJre (ORCPT ); Tue, 3 Dec 2019 04:47:34 -0500 Received: by mail-lf1-f68.google.com with SMTP id f16so2399081lfm.3 for ; Tue, 03 Dec 2019 01:47:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=LBlsPDMutrlKmGK6ispxJ+ONxNie6T+smNqG2/7IGRo=; b=Y949QJfuY8kPUH91G3q2lREJ5bLgeFdqRyUXx3+W2ujbmbNETadIbVHMxY+tPHnmMQ 7YQCavJDwZ4bIWs/r08lFxw8+qMva/308JyQpjZG3Q6RGDxqHdJ6W5Tt0ZXyVakSwrmq BTmzZcSwvzWsEjXJQxpViirKa9sC7WpXQ3pIv+mxPyGd6uztqyI2HNV2hCmDGf34Js/2 vW+gpPhdpLTXlXJBNM7WR2xhkMFzBMgRGNp03TK3QBhswPFl1jswE2daTtn0hKRukYhc 8ke8mRLg2pNF5CjmCBXG2Pkj2coqWavGT0O6TM4koBFwe0HQEQAwIlZrL1Fk00AjPOqJ 5XOQ== 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:references :mime-version:content-disposition:in-reply-to:user-agent; bh=LBlsPDMutrlKmGK6ispxJ+ONxNie6T+smNqG2/7IGRo=; b=EL3xtuYkIPt2SYIjIp9RzlZgmuPzuKjcBTwIG8ePKvn+byI54TClw/6DDVwfBbUgva +6xOCYqNgIXPjWqPKJ4eUQ2EUuihig9GUC6Q9v5bPb3m5PW5CRKe8Am66zpsd3HVdKPa Umu5Eqz0ATdN5FGJd/Ips0xeZLMrzvCuxdbVbbls/HgB0A02GeZB+o2b7l2N/weVAZ/F zqCbAZrakdxIucJV+S9BTTMhGXf60pN3H0QgQWKPmKUSurqLjyBY6BKeGwK+ZHZx0pj+ hffapMZsVARHhuzwjJYihQ3/AY0dgLiLFL60w4hyfNjk7fNOGzxjHv3UvKv2mxIQuj5Z lsNQ== X-Gm-Message-State: APjAAAXoXWieqRRl5y9YpkfQ16reLcRJgu6b8PoHA42W9lABdXBk2fnt QYnGK1CW2wvab9I8//ewjMjiPQ== X-Google-Smtp-Source: APXvYqzKRWDqiRYC85MOhaukLO9IBk6JgBuxKJ5+vxvt4puTqMMjzpNwCwUmN7LgJVCP0G/yEC3aHw== X-Received: by 2002:a19:3f51:: with SMTP id m78mr2257417lfa.70.1575366452524; Tue, 03 Dec 2019 01:47:32 -0800 (PST) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id c193sm969116lfd.28.2019.12.03.01.47.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Dec 2019 01:47:31 -0800 (PST) Received: by box.localdomain (Postfix, from userid 1000) id 9D6C4100494; Tue, 3 Dec 2019 12:47:30 +0300 (+03) Date: Tue, 3 Dec 2019 12:47:30 +0300 From: "Kirill A. Shutemov" To: Wei Yang Cc: 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: <20191203094730.7oh4j5juh3jsx5dk@box> References: <20191128010321.21730-1-richardw.yang@linux.intel.com> <20191128083255.ab5rwj7gvktwunik@box.shutemov.name> <20191128212226.sfrhfs5m3q7m6tly@master> <20191202080315.oqtm3q7cyfkl5rma@box.shutemov.name> <20191202222151.xx4g3ry7mrcselh5@master> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191202222151.xx4g3ry7mrcselh5@master> User-Agent: NeoMutt/20180716 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 10:21:51PM +0000, Wei Yang wrote: > 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? Yeah. I would rather not touch it at all. -- Kirill A. Shutemov