From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 3 Nov 1999 22:41:40 +0100 (CET) From: Ingo Molnar Subject: Re: Why don't we make mmap MAP_SHARED with /dev/zero possible? In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: "Benjamin C.R. LaHaise" Cc: fxzhang@chpc.ict.ac.cn, "linux-mm@kvack.org" List-ID: On Wed, 3 Nov 1999, Benjamin C.R. LaHaise wrote: > > it's now an unconditional __GFP_HIGHMEM in my tree. HIGHMEM gfp() > > allocation automatically falls back to allocate in lowmem, if highmem > > lists are empty. > > I'd like to look through the patches to see how you're doing things before > making any comments. Specifically, I want to look at the buffer head (soon, probably tomorrow) > address thing that was mentioned -- given that the devices that support > addressing memory above 4G will expect a 64 bit address, I don't think the > shift is the right way to go. i introduced bh->b_page _specifically_ to support 64-bit addresses. Below <4GB RAM DMA32 can be supported with no IO-layer changes. Right now it supports up to 2TB DMA64 target space (on 32-bit boxes), which is more than enough. -- mingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://humbolt.geo.uu.nl/Linux-MM/