From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [patch 2/8] mm: introduce VM_MIXEDMAP Date: Mon, 18 Feb 2008 13:59:04 +1100 References: <20080214061657.700804000@suse.de> <20080214062531.335727000@suse.de> In-Reply-To: <20080214062531.335727000@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200802181359.05429.nickpiggin@yahoo.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: npiggin@suse.de Cc: Badari Pulavarty , Dave Kleikamp , anton@au1.ibm.com, Benjamin Herrenschmidt , Carsten Otte , Linus Torvalds , Hugh Dickins , Jared Hulbert , Martin Schwidefsky , Heiko Carstens , linux-mm@kvack.org List-ID: On Thursday 14 February 2008 17:16, npiggin@suse.de wrote: > Introduce a new type of mapping, VM_MIXEDMAP. This is unlike VM_PFNMAP in > that it can support COW mappings of arbitrary ranges including ranges > without struct page (PFNMAP can only support COW in those cases where the > un-COW-ed translations are mapped linearly in the virtual address). > > VM_MIXEDMAP achieves this by refcounting all pfn_valid pages, and not > refcounting !pfn_valid pages (which is not an option for VM_PFNMAP, because > it needs to avoid refcounting pfn_valid pages eg. for /dev/mem mappings). BTW. sorry quilt mail outsmarted me here... I had just intended to send these privately to Badari, Dave, and the other powerpc guys. I wasn't intending this for you Linus, or linux-mm etc. -- 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