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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05F56C25B06 for ; Mon, 15 Aug 2022 01:59:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230054AbiHOB7g (ORCPT ); Sun, 14 Aug 2022 21:59:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229841AbiHOB7d (ORCPT ); Sun, 14 Aug 2022 21:59:33 -0400 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A84612ABC for ; Sun, 14 Aug 2022 18:59:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660528773; x=1692064773; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=kA7lDKgziz+W9ciW3E//tMKB+dBOyRW8yX0jMyo2XGo=; b=bYr3LvQ8Ib3mMfEWtXfO29B1m33aDSLq6iVc/O4HwoOuaaYf69N51Qp3 aASs2j0c2MjAZmVxn6kOMKLbRRPPwXZFdz3dEorr0RUmj78FdobNalgVw Pxa+MsJiqbDvqeqK/BnPEBiCkL+hWBsckDo4knptVAvf+dFiAQN1hTFzL 92iwLR16cdhHQlZnP2u7oBZ71724TSEFBuIxq1aW/orlbQHhawhNURQvL TszQM7/CVfMtTNgK3H3cHMI6S93yc9JgU+GcJTWI4iRfTeLbQhLEybbWO nt/20j2LWFUdkythSO1ebVQlx1tiKizEawidVns4tNrkSVIH0R2Eu/bfW g==; X-IronPort-AV: E=McAfee;i="6400,9594,10439"; a="289441331" X-IronPort-AV: E=Sophos;i="5.93,237,1654585200"; d="scan'208";a="289441331" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Aug 2022 18:59:33 -0700 X-IronPort-AV: E=Sophos;i="5.93,237,1654585200"; d="scan'208";a="582716835" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Aug 2022 18:59:30 -0700 From: "Huang, Ying" To: Haiyue Wang Cc: , , , , , , , Subject: Re: [PATCH v3 1/2] mm: migration: fix the FOLL_GET failure on following huge page References: <20220812084921.409142-1-haiyue.wang@intel.com> <20220815010349.432313-1-haiyue.wang@intel.com> <20220815010349.432313-2-haiyue.wang@intel.com> Date: Mon, 15 Aug 2022 09:59:27 +0800 In-Reply-To: <20220815010349.432313-2-haiyue.wang@intel.com> (Haiyue Wang's message of "Mon, 15 Aug 2022 09:03:48 +0800") Message-ID: <878rnqe074.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Haiyue Wang writes: > Not all huge page APIs support FOLL_GET option, so the __NR_move_pages move_pages() is a syscall, so you can just call it move_pages(), or move_pages() syscall. > will fail to get the page node information for huge page. ~~~~~~~~~ some huge pages? > This is an temporary solution to mitigate the racing fix. Why is it "racing fix"? This isn't a race condition fix. Best Regards, Huang, Ying > After supporting follow huge page by FOLL_GET is done, this fix can be > reverted safely. > > Fixes: 4cd614841c06 ("mm: migration: fix possible do_pages_stat_array racing with memory offline") > Signed-off-by: Haiyue Wang [snip]