From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sun, 20 May 2007 00:26:05 -0700 From: William Lee Irwin III Subject: Re: [rfc] increase struct page size?! Message-ID: <20070520072605.GE19966@holomorphy.com> References: <20070518040854.GA15654@wotan.suse.de> <20070519012530.GB15569@wotan.suse.de> <20070519181501.GC19966@holomorphy.com> <20070519150934.bdabc9b5.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070519150934.bdabc9b5.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Nick Piggin , Christoph Lameter , Linux Kernel Mailing List , Linux Memory Management List , linux-arch@vger.kernel.org List-ID: On Sat, 19 May 2007 11:15:01 -0700 William Lee Irwin III wrote: >> Much the same holds for the atomic_t's; 32 + PAGE_SHIFT is >> 44 bits or more, about as much as is possible, and one reference per >> page per page is not even feasible. Full-length atomic_t's are just >> not necessary. On Sat, May 19, 2007 at 03:09:34PM -0700, Andrew Morton wrote: > You can overflow a page's refcount by mapping it 4G times. That requires > 32GB of pagetable memory. It's quite feasible with remap_file_pages(). Oh dear, worst-case app behavior. I'm just wrong. -- wli -- 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