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=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 DC72CC4321A for ; Thu, 27 Jun 2019 23:38:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B169321726 for ; Thu, 27 Jun 2019 23:38:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726720AbfF0XiO (ORCPT ); Thu, 27 Jun 2019 19:38:14 -0400 Received: from mga07.intel.com ([134.134.136.100]:21471 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726506AbfF0XiO (ORCPT ); Thu, 27 Jun 2019 19:38:14 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Jun 2019 16:38:13 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,425,1557212400"; d="scan'208";a="167595836" Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by orsmga006.jf.intel.com with ESMTP; 27 Jun 2019 16:38:11 -0700 Date: Thu, 27 Jun 2019 16:38:11 -0700 From: Ira Weiny To: Pingfan Liu Cc: Linux-mm@kvack.org, Andrew Morton , Mike Rapoport , "Kirill A. Shutemov" , Thomas Gleixner , John Hubbard , "Aneesh Kumar K.V" , Christoph Hellwig , Keith Busch , Mike Kravetz , Linux-kernel@vger.kernel.org Subject: Re: [PATCHv5] mm/gup: speed up check_and_migrate_cma_pages() on huge page Message-ID: <20190627233805.GA8695@iweiny-DESK2.sc.intel.com> References: <1561612545-28997-1-git-send-email-kernelfans@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1561612545-28997-1-git-send-email-kernelfans@gmail.com> User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 27, 2019 at 01:15:45PM +0800, Pingfan Liu wrote: > Both hugetlb and thp locate on the same migration type of pageblock, since > they are allocated from a free_list[]. Based on this fact, it is enough to > check on a single subpage to decide the migration type of the whole huge > page. By this way, it saves (2M/4K - 1) times loop for pmd_huge on x86, > similar on other archs. > > Furthermore, when executing isolate_huge_page(), it avoid taking global > hugetlb_lock many times, and meanless remove/add to the local link list > cma_page_list. > > Signed-off-by: Pingfan Liu Reviewed-by: Ira Weiny > Cc: Andrew Morton > Cc: Ira Weiny > Cc: Mike Rapoport > Cc: "Kirill A. Shutemov" > Cc: Thomas Gleixner > Cc: John Hubbard > Cc: "Aneesh Kumar K.V" > Cc: Christoph Hellwig > Cc: Keith Busch > Cc: Mike Kravetz > Cc: Linux-kernel@vger.kernel.org > --- > v3 -> v4: fix C language precedence issue > v4 -> v5: drop the check PageCompound() and improve notes > mm/gup.c | 23 +++++++++++++++-------- > 1 file changed, 15 insertions(+), 8 deletions(-) > > diff --git a/mm/gup.c b/mm/gup.c > index ddde097..1deaad2 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -1336,25 +1336,30 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk, > struct vm_area_struct **vmas, > unsigned int gup_flags) > { > - long i; > + long i, step; > bool drain_allow = true; > bool migrate_allow = true; > LIST_HEAD(cma_page_list); > > check_again: > - for (i = 0; i < nr_pages; i++) { > + for (i = 0; i < nr_pages;) { > + > + struct page *head = compound_head(pages[i]); > + > + /* > + * gup may start from a tail page. Advance step by the left > + * part. > + */ > + step = (1 << compound_order(head)) - (pages[i] - head); > /* > * If we get a page from the CMA zone, since we are going to > * be pinning these entries, we might as well move them out > * of the CMA zone if possible. > */ > - if (is_migrate_cma_page(pages[i])) { > - > - struct page *head = compound_head(pages[i]); > - > - if (PageHuge(head)) { > + if (is_migrate_cma_page(head)) { > + if (PageHuge(head)) > isolate_huge_page(head, &cma_page_list); > - } else { > + else { > if (!PageLRU(head) && drain_allow) { > lru_add_drain_all(); > drain_allow = false; > @@ -1369,6 +1374,8 @@ static long check_and_migrate_cma_pages(struct task_struct *tsk, > } > } > } > + > + i += step; > } > > if (!list_empty(&cma_page_list)) { > -- > 2.7.5 >