From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e36.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id m3UKmhWe029316 for ; Wed, 30 Apr 2008 16:48:43 -0400 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m3UKmgZX191956 for ; Wed, 30 Apr 2008 14:48:42 -0600 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m3UKmgDM009401 for ; Wed, 30 Apr 2008 14:48:42 -0600 Date: Wed, 30 Apr 2008 13:48:41 -0700 From: Nishanth Aravamudan Subject: Re: [patch 17/18] x86: add hugepagesz option on 64-bit Message-ID: <20080430204841.GD6903@us.ibm.com> References: <20080423015302.745723000@nick.local0.net> <20080423015431.462123000@nick.local0.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080423015431.462123000@nick.local0.net> Sender: owner-linux-mm@kvack.org Return-Path: To: npiggin@suse.de Cc: akpm@linux-foundation.org, linux-mm@kvack.org, andi@firstfloor.org, kniht@linux.vnet.ibm.com, abh@cray.com, wli@holomorphy.com List-ID: On 23.04.2008 [11:53:19 +1000], npiggin@suse.de wrote: > Add an hugepagesz=... option similar to IA64, PPC etc. to x86-64. > > This finally allows to select GB pages for hugetlbfs in x86 now > that all the infrastructure is in place. Another more basic question ... how do we plan on making these hugepages available to applications. Obviously, an administrator can mount hugetlbfs with pagesize=1G or whatever and then users (with appropriate permissions) can mmap() files created therein. But what about SHM_HUGETLB? It uses a private internal mount of hugetlbfs, which I don't believe I saw a patch to add a pagesize= parameter for. So SHM_HUGETLB will (for now) always get the "default" hugepagesize, right, which should be the same as the legacy size? Given that an architecture may support several hugepage sizes, I have't been able to come up with a good way to extend shmget() to specify the preferred hugepagesize when SHM_HUGETLB is specified. I think for libhugetlbfs purposes, we will probably add another environment variable to control that... Thanks, Nish -- 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