From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 09 Aug 2005 14:16:37 -0700 From: "Martin J. Bligh" Reply-To: "Martin J. Bligh" Subject: Re: [RFC][patch 0/2] mm: remove PageReserved Message-ID: <1162240000.1123622197@flay> In-Reply-To: <20050809204100.B29945@flint.arm.linux.org.uk> References: <42F57FCA.9040805@yahoo.com.au> <200508090710.00637.phillips@arcor.de> <1123562392.4370.112.camel@localhost> <42F83849.9090107@yahoo.com.au> <20050809080853.A25492@flint.arm.linux.org.uk> <523240000.1123598289@[10.10.2.4]> <20050809204100.B29945@flint.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: Russell King Cc: Nick Piggin , ncunningham@cyclades.com, Daniel Phillips , Linux Kernel Mailing List , Linux Memory Management , Hugh Dickins , Linus Torvalds , Andrew Morton , Andrea Arcangeli , Benjamin Herrenschmidt List-ID: --On Tuesday, August 09, 2005 20:41:00 +0100 Russell King wrote: > On Tue, Aug 09, 2005 at 07:38:52AM -0700, Martin J. Bligh wrote: >> pfn_valid() doesn't tell you it's RAM or not - it tells you whether you >> have a backing struct page for that address. Could be an IO mapped device, >> a small memory hole, whatever. > > The only things which have a struct page is RAM. Nothing else does. That's not true at all. Every physical address covered by the machine that we may need to access, plus every small hole we didn't use discontigmem to exclude has a backing struct page. See e820 maps. Unless you're speaking only with respect to ARM, in which case, I'll bow to your knowledge, but it's certainly not true in general ... M. -- 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