From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 28 Jun 2003 17:34:05 -0700 From: "Martin J. Bligh" Subject: Re: 2.5.73-mm2 Message-ID: <56960000.1056846845@[10.10.2.4]> In-Reply-To: <20030628170837.A10514@infradead.org> References: <20030627202130.066c183b.akpm@digeo.com> <20030628155436.GY20413@holomorphy.com> <20030628170837.A10514@infradead.org> 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: Christoph Hellwig , William Lee Irwin III , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: --Christoph Hellwig wrote (on Saturday, June 28, 2003 17:08:37 +0100): > On Sat, Jun 28, 2003 at 08:54:36AM -0700, William Lee Irwin III wrote: >> +config HIGHPMD >> + bool "Allocate 2nd-level pagetables from highmem" >> + depends on HIGHMEM64G >> + help >> + The VM uses one pmd entry for each pagetable page of physical >> + memory allocated. For systems with extreme amounts of highmem, >> + this cannot be tolerated. Setting this option will put >> + userspace 2nd-level pagetables in highmem. > > Does this make sense for !HIGHPTE? In fact does it make sense to > carry along HIGHPTE as an option still? .. Last time I measured it, it had about a 10% overhead in kernel time. Seems like a good thing to keep as an option to me. Bill said he had some other code to alleviate the overhead, but I don't think it's merged ... I'd rather see UKVA (permanently map the pagetables on a per-process basis) merged before it becomes "not an option" - that gets rid of all the kmapping. 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: aart@kvack.org