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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 3E5CAC433ED for ; Mon, 17 May 2021 15:46:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C1DE60FEF for ; Mon, 17 May 2021 15:46:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237901AbhEQPsB (ORCPT ); Mon, 17 May 2021 11:48:01 -0400 Received: from mx2.suse.de ([195.135.220.15]:50786 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243299AbhEQPcE (ORCPT ); Mon, 17 May 2021 11:32:04 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 4636DB23C; Mon, 17 May 2021 15:30:46 +0000 (UTC) Date: Mon, 17 May 2021 16:30:44 +0100 From: Mel Gorman To: Yang Shi Cc: kirill.shutemov@linux.intel.com, ziy@nvidia.com, mhocko@suse.com, ying.huang@intel.com, hughd@google.com, gerald.schaefer@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [v2 PATCH 7/7] mm: thp: skip make PMD PROT_NONE if THP migration is not supported Message-ID: <20210517153044.GZ3672@suse.de> References: <20210413212416.3273-1-shy828301@gmail.com> <20210413212416.3273-8-shy828301@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20210413212416.3273-8-shy828301@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 13, 2021 at 02:24:16PM -0700, Yang Shi wrote: > A quick grep shows x86_64, PowerPC (book3s), ARM64 and S390 support both > NUMA balancing and THP. But S390 doesn't support THP migration so NUMA > balancing actually can't migrate any misplaced pages. > > Skip make PMD PROT_NONE for such case otherwise CPU cycles may be wasted > by pointless NUMA hinting faults on S390. > > Signed-off-by: Yang Shi Acked-by: Mel Gorman -- Mel Gorman SUSE Labs