From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 11 Jun 2008 13:52:07 -0700 From: Andrew Morton Subject: Re: [v4][PATCH 2/2] fix large pages in pagemap Message-Id: <20080611135207.32a46267.akpm@linux-foundation.org> In-Reply-To: <1213216462.20475.36.camel@nimitz> References: <20080611180228.12987026@kernel> <20080611180230.7459973B@kernel> <20080611123724.3a79ea61.akpm@linux-foundation.org> <1213213980.20045.116.camel@calx> <20080611131108.61389481.akpm@linux-foundation.org> <1213216462.20475.36.camel@nimitz> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Dave Hansen Cc: mpm@selenic.com, hans.rosenfeld@amd.com, linux-mm@kvack.org, hugh@veritas.com, riel@redhat.com List-ID: On Wed, 11 Jun 2008 13:34:22 -0700 Dave Hansen wrote: > On Wed, 2008-06-11 at 13:11 -0700, Andrew Morton wrote: > > Really? There already a couple of pmd_huge() tests in mm/memory.c and > > Rik's access_process_vm-device-memory-infrastructure.patch adds > > another one. > > We're not supposed to ever hit the one in follow_page() because there > are: > > if (is_vm_hugetlb_page(vma)) { > i = follow_hugetlb_page(mm, vma, pages, vmas, > &start, &len, i, write); > continue; > } > > checks before them like in get_user_pages(); > > The other mm/memory.c call is under alloc_vm_area(), and that's > supposedly only used on kernel addresses. I don't think we even have > Linux pagetables for kernel addresses on ppc. > access_process_vm-device-memory-infrastructure.patch is a powerpc feature, and it uses pmd_huge(). Am I missing something, or is pmd_huge() a whopping big grenade for x86 developers to toss at non-x86 architectures? It seems quite dangerous. -- 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