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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 B7940C1B0F1 for ; Wed, 20 Jun 2018 02:17:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6EE53205C9 for ; Wed, 20 Jun 2018 02:17:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6EE53205C9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ah.jp.nec.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754157AbeFTCRd convert rfc822-to-8bit (ORCPT ); Tue, 19 Jun 2018 22:17:33 -0400 Received: from tyo161.gate.nec.co.jp ([114.179.232.161]:56942 "EHLO tyo161.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753758AbeFTCRc (ORCPT ); Tue, 19 Jun 2018 22:17:32 -0400 Received: from mailgate02.nec.co.jp ([114.179.233.122]) by tyo161.gate.nec.co.jp (8.15.1/8.15.1) with ESMTPS id w5K2FjIr016628 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 20 Jun 2018 11:15:45 +0900 Received: from mailsv02.nec.co.jp (mailgate-v.nec.co.jp [10.204.236.94]) by mailgate02.nec.co.jp (8.15.1/8.15.1) with ESMTP id w5K2FjkZ008492; Wed, 20 Jun 2018 11:15:45 +0900 Received: from mail01b.kamome.nec.co.jp (mail01b.kamome.nec.co.jp [10.25.43.2]) by mailsv02.nec.co.jp (8.15.1/8.15.1) with ESMTP id w5K2CsV7017583; Wed, 20 Jun 2018 11:15:45 +0900 Received: from bpxc99gp.gisp.nec.co.jp ([10.38.151.148] [10.38.151.148]) by mail02.kamome.nec.co.jp with ESMTP id BT-MMP-1335395; Wed, 20 Jun 2018 11:14:54 +0900 Received: from BPXM23GP.gisp.nec.co.jp ([10.38.151.215]) by BPXC20GP.gisp.nec.co.jp ([10.38.151.148]) with mapi id 14.03.0319.002; Wed, 20 Jun 2018 11:14:53 +0900 From: Naoya Horiguchi To: Pavel Tatashin CC: "steven.sistare@oracle.com" , "daniel.m.jordan@oracle.com" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , "mhocko@suse.com" , "linux-mm@kvack.org" , "osalvador@suse.de" , "willy@infradead.org" , "mingo@kernel.org" , "dan.j.williams@intel.com" , "ying.huang@intel.com" Subject: Re: [PATCH] mm: skip invalid pages block at a time in zero_resv_unresv Thread-Topic: [PATCH] mm: skip invalid pages block at a time in zero_resv_unresv Thread-Index: AQHUBMGZzpEnEUsumkebRnt6zmuZMaRn2I4A Date: Wed, 20 Jun 2018 02:14:53 +0000 Message-ID: <20180620021452.GA7241@hori1.linux.bs1.fc.nec.co.jp> References: <20180615155733.1175-1-pasha.tatashin@oracle.com> In-Reply-To: <20180615155733.1175-1-pasha.tatashin@oracle.com> Accept-Language: en-US, ja-JP Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.51.8.80] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <5C4BEA7B6AF786479FE83EE4EF287E8D@gisp.nec.co.jp> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-TM-AS-MML: disable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 15, 2018 at 11:57:33AM -0400, Pavel Tatashin wrote: > The role of zero_resv_unavail() is to make sure that every struct page that > is allocated but is not backed by memory that is accessible by kernel is > zeroed and not in some uninitialized state. > > Since struct pages are allocated in blocks (2M pages in x86 case), we can > skip pageblock_nr_pages at a time, when the first one is found to be > invalid. > > This optimization may help since now on x86 every hole in e820 maps > is marked as reserved in memblock, and thus will go through this function. > > This function is called before sched_clock() is initialized, so I used my > x86 early boot clock patches to measure the performance improvement. > > With 1T hole on i7-8700 currently we would take 0.606918s of boot time, but > with this optimization 0.001103s. > > Signed-off-by: Pavel Tatashin Looks good to me, thanks! Reviewed-by: Naoya Horiguchi > --- > mm/page_alloc.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 1521100f1e63..94f1b3201735 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -6404,8 +6404,11 @@ void __paginginit zero_resv_unavail(void) > pgcnt = 0; > for_each_resv_unavail_range(i, &start, &end) { > for (pfn = PFN_DOWN(start); pfn < PFN_UP(end); pfn++) { > - if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) > + if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) { > + pfn = ALIGN_DOWN(pfn, pageblock_nr_pages) > + + pageblock_nr_pages - 1; > continue; > + } > mm_zero_struct_page(pfn_to_page(pfn)); > pgcnt++; > } > -- > 2.17.1 > >