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=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 E883CC432C3 for ; Tue, 3 Dec 2019 15:14:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BF6B82073C for ; Tue, 3 Dec 2019 15:14:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Kb/eqh+T" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726673AbfLCPOq (ORCPT ); Tue, 3 Dec 2019 10:14:46 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:39034 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726057AbfLCPOq (ORCPT ); Tue, 3 Dec 2019 10:14:46 -0500 Received: by mail-wm1-f65.google.com with SMTP id s14so3886050wmh.4 for ; Tue, 03 Dec 2019 07:14:44 -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=At8iFqCdCBYnD7o5MP8ED77hrI5cydOyTaRg33rZGY0=; b=Kb/eqh+TmcyP7ISv9YF1n9WOLPthOR59gjDrbO+aqdh0PKu63YqBFofOvFXUegSz0s +JnP7jzew187S51fP+wauP9QptTbIIev6OYOQjg8wC6I/Lfx9heH00Dv40V3fEC/cNFn xE4kEtos0sp1d1RjH+RQy42bUTRp+PkaRICSFwyg/8C87p5h4TvGNzfWAo+asgd6sjKn 3NRVMstYQRDGY7jxwK1T20aX9z4FRhs0t+t+tEh3ckqA37fYvCZcTNy8CZSyJGUiEz2p eXv+lcXbPijPn92sVl80wIPKXezqrWSUS3Oj7xHZ/4lva1nn5v2LYoROJS5cIfOoApfJ IxNA== 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=At8iFqCdCBYnD7o5MP8ED77hrI5cydOyTaRg33rZGY0=; b=WNks2EwdgakP9dcN7LL/Eone60oTDVuJrxO6dMYVLVPsOjESU9yt/wwqvckH3+HIfk JLxh17x1xVwUwY0/bcpFd3nLufNfRdssUAcXX1ktQLLTv3T76zE9C4x7XhSh/pHKAyyy ZYoOftWNN8pdOTQCOeTYEabO2n5IGubA00GUSy5sTC3Io0A+c6nuBu6LXGWO5xM59Lzu TChVKcRDol1UK1cg7MSOXwh6B8PpwlvUeROwWfg3vFx+gITMLRRgfUXSylnF8MHpvlej kPKCzkujHQ71TOz3QTJKxAhfZlNrvr8eBPzbQjC3ITuL3uAHRzoI/lZoaEwW/VgMb0Mu Qfog== X-Gm-Message-State: APjAAAWY7aGgvQ2Q5XkGzH2ZV0GoUkNSHpFh/jtdoCkPQOroGQKag0GB EnI8o5P36uKBgvYJcb3vLfg= X-Google-Smtp-Source: APXvYqyn1eDIJhrVNE8kf9OU/5CbYkTPWMhI8hktvOaZ8lmkm+I4ulwHSwtA+b/6q7TkrkZX/sGJWA== X-Received: by 2002:a7b:c759:: with SMTP id w25mr10077752wmk.15.1575386083548; Tue, 03 Dec 2019 07:14:43 -0800 (PST) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id h2sm4157452wrt.45.2019.12.03.07.14.42 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 03 Dec 2019 07:14:42 -0800 (PST) Date: Tue, 3 Dec 2019 15:14:42 +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: <20191203151442.pftcc2azieulepzp@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> <20191202222151.xx4g3ry7mrcselh5@master> <20191203094730.7oh4j5juh3jsx5dk@box> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191203094730.7oh4j5juh3jsx5dk@box> 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 Tue, Dec 03, 2019 at 12:47:30PM +0300, Kirill A. Shutemov wrote: >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. > Got it, thanks. >-- > Kirill A. Shutemov -- Wei Yang Help you, Help me