From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 30 Sep 1999 12:05:24 -0400 (EDT) From: James Simmons Subject: Re: mm->mmap_sem 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: "Stephen C. Tweedie" , Marcus Sundberg , linux-mm@kvack.org List-ID: > > Here is another question since its very expensive putting another process > > to sleep. If the process owns both the accel engine and framebuffer then I > > should be able to put the process to sleep while the accel engine is > > running? Since the process is asleep it can't acces the framebuffer but > > the accel engine is still running on the card. > > Oh gawd... How much does the kernel know about the accelerator? Its a memory region thats mmap to userspace. Thats all it knows. By the way what I suggested above would work. > Something to consider is that the 'right' solution might be to make the > kernel pass console handling to a user task -- have you ever considered > that? Uhm. No. I don't think that will work for what I want. > > These are mmapped regions. So locking out the kernel will not help. You > > have to prevent userland from accessing the memory region to prevent the > > machine from locking. > > And the performance-correct way to do this is with a cooperative lock that > is *not part* of the mmap'd region. That still doesn't prevent a rogue aplication from locking the machine on purpose. A application could just ignore the locks. -- 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/