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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 E30B2C56201 for ; Sun, 22 Nov 2020 06:17:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3EA620885 for ; Sun, 22 Nov 2020 06:17:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="kuXrdfOU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727369AbgKVGRZ (ORCPT ); Sun, 22 Nov 2020 01:17:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:55960 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726957AbgKVGRY (ORCPT ); Sun, 22 Nov 2020 01:17:24 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A8DFB21D81; Sun, 22 Nov 2020 06:17:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1606025843; bh=nNBCUnSKcDrkF+Ddihz6zZ5lsSOminmqsaiRjEho7Es=; h=Date:From:To:Subject:In-Reply-To:From; b=kuXrdfOU8OXzCvTn62acRPePkNnw84tGQeloRY+6uoWiBBDCIWjIUNp/YOyyDwU3g +WVNMZWQ/NFxMO0qxwbPaym/KkVsp11PlrZa2AKYtM+ElS3MyMzgG6rTgqoXSrn+bp 44knvaupA1uKWmFlrwuQtI2sGztUvcpgFPMKNKvE= Date: Sat, 21 Nov 2020 22:17:22 -0800 From: Andrew Morton To: akpm@linux-foundation.org, feng.tang@intel.com, hannes@cmpxchg.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, rong.a.chen@intel.com, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org, zhengjun.xing@linux.intel.com Subject: [patch 8/8] mm: fix madvise WILLNEED performance problem Message-ID: <20201122061722.Tef3ViFuW%akpm@linux-foundation.org> In-Reply-To: <20201121221631.948ae4655e913a319d61700a@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: "Matthew Wilcox (Oracle)" Subject: mm: fix madvise WILLNEED performance problem The calculation of the end page index was incorrect, leading to a regression of 70% when running stress-ng. With this fix, we instead see a performance improvement of 3%. Link: https://lkml.kernel.org/r/20201109134851.29692-1-willy@infradead.org Fixes: e6e88712e43b ("mm: optimise madvise WILLNEED") Signed-off-by: Matthew Wilcox (Oracle) Reported-by: kernel test robot Tested-by: Xing Zhengjun Acked-by: Johannes Weiner Cc: William Kucharski Cc: Feng Tang Cc: "Chen, Rong A" Signed-off-by: Andrew Morton --- mm/madvise.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/madvise.c~mm-fix-madvise-willneed-performance-problem +++ a/mm/madvise.c @@ -226,7 +226,7 @@ static void force_shm_swapin_readahead(s struct address_space *mapping) { XA_STATE(xas, &mapping->i_pages, linear_page_index(vma, start)); - pgoff_t end_index = end / PAGE_SIZE; + pgoff_t end_index = linear_page_index(vma, end + PAGE_SIZE - 1); struct page *page; rcu_read_lock(); _