From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sp1n293en1.watson.ibm.com (sp1n293en1.watson.ibm.com [9.2.112.57]) by igw3.watson.ibm.com (8.11.4/8.11.4) with ESMTP id g07IXRn19758 for ; Mon, 7 Jan 2002 13:33:27 -0500 Received: from watson.ibm.com (discohall.watson.ibm.com [9.2.17.22]) by sp1n293en1.watson.ibm.com (8.11.4/8.11.4) with ESMTP id g07IXRn41278 for ; Mon, 7 Jan 2002 13:33:27 -0500 Message-ID: <3C39EAD1.20CDF9CE@watson.ibm.com> Date: Mon, 07 Jan 2002 13:37:05 -0500 From: "Raymond B. Jennings III" Reply-To: raymondj@watson.ibm.com MIME-Version: 1.0 Subject: Hole in kernel virtual address space. Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org List-ID: I've asked this question in the past but have yet to get any insight to it. Basically there appears to be a hole when HIGHMEM is turned on in the kernel. With HIGHMEM turned off: VMALLOC_END = FIXADDR_START - 2*PAGE_SIZE VMALLOC_END = (FFFFE000h - 4*PAGE_SIZE) - 2*PAGE_SIZE (Pretty close to the 4GB boundary) With HIGHMEM turned on: VMALLOC_END = PKMAP_BASE - 2*PAGE_SIZE I realize you need room for the pkmap_count array but the array only allows for 1024 pages. If PKMAP_BASE = FE000000h then this fills the address space upto FE400000. What is being used in the remaining section of the address space? Thanks. -- 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/