From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753497AbcHaVfO (ORCPT ); Wed, 31 Aug 2016 17:35:14 -0400 Received: from mga05.intel.com ([192.55.52.43]:18262 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751997AbcHaVfM (ORCPT ); Wed, 31 Aug 2016 17:35:12 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,263,1470726000"; d="scan'208";a="3256755" From: Andi Kleen To: Mel Gorman Cc: "Huang\, Ying" , Andrew Morton , tim.c.chen@intel.com, dave.hansen@intel.com, andi.kleen@intel.com, aaron.lu@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , Shaohua Li , Minchan Kim , Rik van Riel , Tejun Heo , Wu Fengguang Subject: Re: [PATCH -v2] mm: Don't use radix tree writeback tags for pages in swap cache References: <1472578089-5560-1-git-send-email-ying.huang@intel.com> <20160831091459.GY8119@techsingularity.net> <87oa49m0hn.fsf@yhuang-mobile.sh.intel.com> <20160831153908.GA8119@techsingularity.net> Date: Wed, 31 Aug 2016 14:35:11 -0700 In-Reply-To: <20160831153908.GA8119@techsingularity.net> (Mel Gorman's message of "Wed, 31 Aug 2016 16:39:08 +0100") Message-ID: <87vaygzkog.fsf@tassilo.jf.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mel Gorman writes: > > __GFP_BITS_SHIFT + 5 (AS_NO_WRITEBACK_TAGS) = 31 > > mapping->flags is a combination of AS and GFP flags so increasing > __GFP_BITS_SHIFT overflows mapping->flags on 32-bit as gfp_t is an > unsigned int. Couldn't we just split mapping->flags into two fields? I'm sure more GFP bits will be needed eventually. -Andi From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yb0-f200.google.com (mail-yb0-f200.google.com [209.85.213.200]) by kanga.kvack.org (Postfix) with ESMTP id 4B0D86B025E for ; Wed, 31 Aug 2016 17:35:13 -0400 (EDT) Received: by mail-yb0-f200.google.com with SMTP id 18so9557588ybc.3 for ; Wed, 31 Aug 2016 14:35:13 -0700 (PDT) Received: from mga05.intel.com (mga05.intel.com. [192.55.52.43]) by mx.google.com with ESMTPS id 77si1691244pft.11.2016.08.31.14.35.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 31 Aug 2016 14:35:12 -0700 (PDT) From: Andi Kleen Subject: Re: [PATCH -v2] mm: Don't use radix tree writeback tags for pages in swap cache References: <1472578089-5560-1-git-send-email-ying.huang@intel.com> <20160831091459.GY8119@techsingularity.net> <87oa49m0hn.fsf@yhuang-mobile.sh.intel.com> <20160831153908.GA8119@techsingularity.net> Date: Wed, 31 Aug 2016 14:35:11 -0700 In-Reply-To: <20160831153908.GA8119@techsingularity.net> (Mel Gorman's message of "Wed, 31 Aug 2016 16:39:08 +0100") Message-ID: <87vaygzkog.fsf@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: "Huang, Ying" , Andrew Morton , tim.c.chen@intel.com, dave.hansen@intel.com, andi.kleen@intel.com, aaron.lu@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , Shaohua Li , Minchan Kim , Rik van Riel , Tejun Heo , Wu Fengguang Mel Gorman writes: > > __GFP_BITS_SHIFT + 5 (AS_NO_WRITEBACK_TAGS) = 31 > > mapping->flags is a combination of AS and GFP flags so increasing > __GFP_BITS_SHIFT overflows mapping->flags on 32-bit as gfp_t is an > unsigned int. Couldn't we just split mapping->flags into two fields? I'm sure more GFP bits will be needed eventually. -Andi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org