From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751275AbdCNXNg (ORCPT ); Tue, 14 Mar 2017 19:13:36 -0400 Received: from mga01.intel.com ([192.55.52.88]:27969 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750796AbdCNXNf (ORCPT ); Tue, 14 Mar 2017 19:13:35 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,166,1486454400"; d="scan'208";a="1108496627" Message-ID: <1489533213.2733.33.camel@linux.intel.com> Subject: Re: [PATCH -mm -v6 3/9] mm, THP, swap: Add swap cluster allocate/free functions From: Tim Chen To: "Huang, Ying" , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrea Arcangeli , "Kirill A . Shutemov" , Hugh Dickins , Shaohua Li , Minchan Kim , Rik van Riel Date: Tue, 14 Mar 2017 16:13:33 -0700 In-Reply-To: <20170308072613.17634-4-ying.huang@intel.com> References: <20170308072613.17634-1-ying.huang@intel.com> <20170308072613.17634-4-ying.huang@intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.5.2 (3.18.5.2-1.fc23) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2017-03-08 at 15:26 +0800, Huang, Ying wrote: > From: Huang Ying > > The swap cluster allocation/free functions are added based on the > existing swap cluster management mechanism for SSD.  These functions > don't work for the rotating hard disks because the existing swap cluster > management mechanism doesn't work for them.  The hard disks support may > be added if someone really need it.  But that needn't be included in > this patchset. > > This will be used for the THP (Transparent Huge Page) swap support. > Where one swap cluster will hold the contents of each THP swapped out. > > Cc: Andrea Arcangeli > Cc: Kirill A. Shutemov > Cc: Hugh Dickins > Cc: Shaohua Li > Cc: Minchan Kim > Cc: Rik van Riel > Signed-off-by: "Huang, Ying" > --- >  mm/swapfile.c | 217 +++++++++++++++++++++++++++++++++++++++++----------------- >  1 file changed, 156 insertions(+), 61 deletions(-) > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index a744604384ff..91876c33114b 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -378,6 +378,14 @@ static void swap_cluster_schedule_discard(struct swap_info_struct *si, >   schedule_work(&si->discard_work); >  } >   > +static void __free_cluster(struct swap_info_struct *si, unsigned long idx) > +{ > + struct swap_cluster_info *ci = si->cluster_info; > + > + cluster_set_flag(ci + idx, CLUSTER_FLAG_FREE); > + cluster_list_add_tail(&si->free_clusters, ci, idx); > +} > + >  /* >   * Doing discard actually. After a cluster discard is finished, the cluster >   * will be added to free cluster list. caller should hold si->lock. > @@ -398,10 +406,7 @@ static void swap_do_scheduled_discard(struct swap_info_struct *si) >   >   spin_lock(&si->lock); >   ci = lock_cluster(si, idx * SWAPFILE_CLUSTER); > - cluster_set_flag(ci, CLUSTER_FLAG_FREE); > - unlock_cluster(ci); > - cluster_list_add_tail(&si->free_clusters, info, idx); > - ci = lock_cluster(si, idx * SWAPFILE_CLUSTER); > + __free_cluster(si, idx); >   memset(si->swap_map + idx * SWAPFILE_CLUSTER, >   0, SWAPFILE_CLUSTER); >   unlock_cluster(ci); The __free_cluster definition and the above change to eliminate the extra unlock_cluster and lock_cluster can perhaps be broken up as a separate patch.  It can be independent of THP changes. Tim