Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933201AbdC3AqC (ORCPT ); Wed, 29 Mar 2017 20:46:02 -0400 Received: from mga09.intel.com ([134.134.136.24]:44293 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932757AbdC3AqB (ORCPT ); Wed, 29 Mar 2017 20:46:01 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.36,244,1486454400"; d="scan'208";a="1148602210" From: "Huang\, Ying" To: Johannes Weiner Cc: "Huang\, Ying" , Andrew Morton , , , Hugh Dickins , Shaohua Li , Minchan Kim , Rik van Riel Subject: Re: [PATCH -mm -v7 1/9] mm, swap: Make swap cluster size same of THP size on x86_64 References: <20170328053209.25876-1-ying.huang@intel.com> <20170328053209.25876-2-ying.huang@intel.com> <20170329165522.GA31821@cmpxchg.org> Date: Thu, 30 Mar 2017 08:45:56 +0800 In-Reply-To: <20170329165522.GA31821@cmpxchg.org> (Johannes Weiner's message of "Wed, 29 Mar 2017 12:55:22 -0400") Message-ID: <87o9wjtwvv.fsf@yhuang-dev.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1216 Lines: 41 Johannes Weiner writes: > On Tue, Mar 28, 2017 at 01:32:01PM +0800, Huang, Ying wrote: >> @@ -499,6 +499,19 @@ config FRONTSWAP >> >> If unsure, say Y to enable frontswap. >> >> +config ARCH_USES_THP_SWAP_CLUSTER >> + bool >> + default n > > This is fine. > >> +config THP_SWAP_CLUSTER >> + bool >> + depends on SWAP && TRANSPARENT_HUGEPAGE && ARCH_USES_THP_SWAP_CLUSTER >> + default y >> + help >> + Use one swap cluster to hold the contents of the THP >> + (Transparent Huge Page) swapped out. The size of the swap >> + cluster will be same as that of THP. > > But this is a super weird thing to ask the user. How would they know > what to say, if we don't know? I don't think this should be a config > knob at all. Merge the two config items into a simple The user will not see this, because there is no string after "bool" to let user to select it. The help here is for document only, so that architecture developers could know what this is for. > config THP_SWAP_CLUSTER > bool > default n > > and let the archs with reasonable THP sizes select it. This will have same effect as the original solution except the document is removed. Best Regards, Huang, Ying