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 7A2C8ECDFAA for ; Sat, 14 Jul 2018 12:53:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E2E6208CE for ; Sat, 14 Jul 2018 12:53:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3E2E6208CE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.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 S1731087AbeGNNMR (ORCPT ); Sat, 14 Jul 2018 09:12:17 -0400 Received: from mga05.intel.com ([192.55.52.43]:8251 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730897AbeGNNMQ (ORCPT ); Sat, 14 Jul 2018 09:12:16 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Jul 2018 05:53:16 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,352,1526367600"; d="scan'208";a="215988230" Received: from yhuang-dev.sh.intel.com (HELO yhuang-dev) ([10.239.13.118]) by orsmga004.jf.intel.com with ESMTP; 14 Jul 2018 05:53:13 -0700 From: "Huang\, Ying" To: Daniel Jordan Cc: Andrew Morton , , , Michal Hocko , "Johannes Weiner" , Shaohua Li , Hugh Dickins , Minchan Kim , Rik van Riel , Dan Williams , Dave Hansen Subject: Re: [PATCH 3/6] swap: Unify normal/huge code path in swap_page_trans_huge_swapped() References: <20180712233636.20629-1-ying.huang@intel.com> <20180712233636.20629-4-ying.huang@intel.com> <20180713201557.bjt4tj26nisgdmmi@ca-dmjordan1.us.oracle.com> Date: Sat, 14 Jul 2018 20:53:12 +0800 In-Reply-To: <20180713201557.bjt4tj26nisgdmmi@ca-dmjordan1.us.oracle.com> (Daniel Jordan's message of "Fri, 13 Jul 2018 13:15:57 -0700") Message-ID: <87efg6dlmv.fsf@yhuang-dev.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Daniel Jordan writes: > On Fri, Jul 13, 2018 at 07:36:33AM +0800, Huang, Ying wrote: >> diff --git a/mm/swapfile.c b/mm/swapfile.c >> index 75c84aa763a3..160f78072667 100644 >> --- a/mm/swapfile.c >> +++ b/mm/swapfile.c >> @@ -270,7 +270,10 @@ static inline void cluster_set_null(struct swap_cluster_info *info) >> >> static inline bool cluster_is_huge(struct swap_cluster_info *info) >> { >> - return info->flags & CLUSTER_FLAG_HUGE; >> + if (IS_ENABLED(CONFIG_THP_SWAP)) >> + return info->flags & CLUSTER_FLAG_HUGE; >> + else >> + return false; >> } >> >> static inline void cluster_clear_huge(struct swap_cluster_info *info) >> @@ -1489,9 +1492,6 @@ static bool swap_page_trans_huge_swapped(struct swap_info_struct *si, >> int i; >> bool ret = false; >> >> - if (!IS_ENABLED(CONFIG_THP_SWAP)) >> - return swap_swapcount(si, entry) != 0; > > This tests the value returned from swap_count, > >> - >> ci = lock_cluster_or_swap_info(si, offset); >> if (!ci || !cluster_is_huge(ci)) { >> if (map[roffset] != SWAP_HAS_CACHE) > > and now we're testing > > map[roffset] != SWAP_HAS_CACHE > > instead. The two seem to mean the same thing here, since the swap slot hasn't > been freed to the global pool and so can't be 0, but it might be better for > consistency and clarity to use swap_count here, and a few lines down too > > for (i = 0; i < SWAPFILE_CLUSTER; i++) { > if (map[offset + i] != SWAP_HAS_CACHE) { > > since swap_count seems to be used everywhere else for this. Yes. swap_count() looks better here. Will change this. Best Regards, Huang, Ying