From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [patch] hugetlb: remove dummy definitions of HPAGE_MASK and HPAGE_SIZE Date: Tue, 22 Nov 2011 12:41:55 -0800 Message-ID: References: <1321567050-13197-1-git-send-email-ddaney.cavm@gmail.com> <4ECACF68.3020701@gmail.com> <4ECADD83.3090108@caviumnetworks.com> <20111121155024.33b1b881.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga02.intel.com ([134.134.136.20]:20464 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755826Ab1KVUl4 (ORCPT ); Tue, 22 Nov 2011 15:41:56 -0500 In-Reply-To: <20111121155024.33b1b881.akpm@linux-foundation.org> (Andrew Morton's message of "Mon, 21 Nov 2011 15:50:24 -0800") Sender: linux-arch-owner@vger.kernel.org List-ID: To: Andrew Morton Cc: Linus Torvalds , David Daney , David Daney , David Rientjes , "linux-mips@linux-mips.org" , "ralf@linux-mips.org" , "linux-kernel@vger.kernel.org" , David Daney , "linux-arch@vger.kernel.org" , Robin Holt Andrew Morton writes: >> >> I wish people whose code had stuff like that would take a deep look at it. >> > > The original decision way back when was that huge pages shouldn't mess > up the core VM too much. One way in which we addressed that was to IMHO this decision should really be revisited now. Originally hugetlb was pretty simple, but these days it has most of the functionality of a full VM now. In fact with THP we have 3 different VM systems now, all subtle different with different issues. And with THP hugetlb will be even more widely used than it is today. On the other hand there are strange gaps now, like shared memory doesn't work with THP, but only with hugetlbfs. It would be far better to think about unifying these three VMs. Then with less ifdefs it would also not need hacks like this anymore. -Andi -- ak@linux.intel.com -- Speaking for myself only From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 22 Nov 2011 21:42:09 +0100 (CET) Received: from mga09.intel.com ([134.134.136.24]:42641 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1903818Ab1KVUmD (ORCPT ); Tue, 22 Nov 2011 21:42:03 +0100 Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP; 22 Nov 2011 12:41:55 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,352,1309762800"; d="scan'208";a="78932275" Received: from tassilo.jf.intel.com ([10.7.201.108]) by orsmga001.jf.intel.com with ESMTP; 22 Nov 2011 12:41:55 -0800 Received: by tassilo.jf.intel.com (Postfix, from userid 501) id 22136240F46; Tue, 22 Nov 2011 12:41:55 -0800 (PST) From: Andi Kleen To: Andrew Morton Cc: Linus Torvalds , David Daney , David Daney , David Rientjes , "linux-mips\@linux-mips.org" , "ralf\@linux-mips.org" , "linux-kernel\@vger.kernel.org" , David Daney , "linux-arch\@vger.kernel.org" , Robin Holt Subject: Re: [patch] hugetlb: remove dummy definitions of HPAGE_MASK and HPAGE_SIZE References: <1321567050-13197-1-git-send-email-ddaney.cavm@gmail.com> <4ECACF68.3020701@gmail.com> <4ECADD83.3090108@caviumnetworks.com> <20111121155024.33b1b881.akpm@linux-foundation.org> Date: Tue, 22 Nov 2011 12:41:55 -0800 In-Reply-To: <20111121155024.33b1b881.akpm@linux-foundation.org> (Andrew Morton's message of "Mon, 21 Nov 2011 15:50:24 -0800") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-archive-position: 31930 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: andi@firstfloor.org Precedence: bulk X-list: linux-mips Return-Path: X-Keywords: X-UID: 19008 Andrew Morton writes: >> >> I wish people whose code had stuff like that would take a deep look at it. >> > > The original decision way back when was that huge pages shouldn't mess > up the core VM too much. One way in which we addressed that was to IMHO this decision should really be revisited now. Originally hugetlb was pretty simple, but these days it has most of the functionality of a full VM now. In fact with THP we have 3 different VM systems now, all subtle different with different issues. And with THP hugetlb will be even more widely used than it is today. On the other hand there are strange gaps now, like shared memory doesn't work with THP, but only with hugetlbfs. It would be far better to think about unifying these three VMs. Then with less ifdefs it would also not need hacks like this anymore. -Andi -- ak@linux.intel.com -- Speaking for myself only