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 e31.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id m5BKFPDj030812 for ; Wed, 11 Jun 2008 16:15:25 -0400 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m5BKFJfE133882 for ; Wed, 11 Jun 2008 14:15:19 -0600 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m5BKFI7I019085 for ; Wed, 11 Jun 2008 14:15:18 -0600 Subject: Re: [v4][PATCH 2/2] fix large pages in pagemap From: Dave Hansen In-Reply-To: <1213213980.20045.116.camel@calx> References: <20080611180228.12987026@kernel> <20080611180230.7459973B@kernel> <20080611123724.3a79ea61.akpm@linux-foundation.org> <1213213980.20045.116.camel@calx> Content-Type: text/plain Date: Wed, 11 Jun 2008 13:15:16 -0700 Message-Id: <1213215316.20475.22.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Matt Mackall Cc: Andrew Morton , hans.rosenfeld@amd.com, linux-mm@kvack.org, Hugh Dickins , "ADAM G. LITKE [imap]" , Nishanth Aravamudan List-ID: On Wed, 2008-06-11 at 14:53 -0500, Matt Mackall wrote: > > > I don't get it. Why can't we just stick a > > > > if (pmd_huge(pmd)) > > continue; > > > > into pagemap_pte_range()? Or something like that. > > That's certainly what you'd hope to be able to do, yes. > > If I recall the earlier discussion, some arches with huge pages can > only > identify them via a VMA. Obviously, any arch with hardware that walks > our pagetables directly must be able to identify huge pages directly > from those tables, but I think PPC and a couple others that don't have > hardware TLB fill fail to store such a bit in the tables at all. Yeah, the ppc (and more) huge pmd entries are just the address of the huge page. I would love to get all of them converted so we could use pmd_huge() on them, eventually. But, that's a much bigger undertaking. -- Dave -- 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