From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 09 Aug 2005 07:38:52 -0700 From: "Martin J. Bligh" Reply-To: "Martin J. Bligh" Subject: Re: [RFC][patch 0/2] mm: remove PageReserved Message-ID: <523240000.1123598289@[10.10.2.4]> In-Reply-To: <20050809080853.A25492@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> 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 , Nick Piggin Cc: ncunningham@cyclades.com, Daniel Phillips , Linux Kernel Mailing List , Linux Memory Management , Hugh Dickins , Linus Torvalds , Andrew Morton , Andrea Arcangeli , Benjamin Herrenschmidt List-ID: --Russell King wrote (on Tuesday, August 09, 2005 08:08:53 +0100): > On Tue, Aug 09, 2005 at 02:59:53PM +1000, Nick Piggin wrote: >> That would work for swsusp, but there are other users that want to >> know if a struct page is valid ram (eg. ioremap), so in that case >> swsusp would not be able to mess with the flag. > > The usage of "valid ram" here is confusing - that's not what PageReserved > is all about. It's about valid RAM which is managed by method other > than the usual page counting. Non-reserved RAM is also valid RAM, but > is managed by the kernel in the usual way. > > The former is available for remap_pfn_range and ioremap, the latter is > not. > > On the other hand, the validity of an apparant RAM address can only be > tested using its pfn with pfn_valid(). > > Can we straighten out the terminology so it's less confusing please? 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. 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