Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261679AbUKIUZa (ORCPT ); Tue, 9 Nov 2004 15:25:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261681AbUKIUZ3 (ORCPT ); Tue, 9 Nov 2004 15:25:29 -0500 Received: from alog0321.analogic.com ([208.224.222.97]:2688 "EHLO chaos.analogic.com") by vger.kernel.org with ESMTP id S261679AbUKIUZS (ORCPT ); Tue, 9 Nov 2004 15:25:18 -0500 Date: Tue, 9 Nov 2004 15:25:12 -0500 (EST) From: linux-os Reply-To: linux-os@analogic.com To: Mike Waychison cc: Linux kernel Subject: Re: More linux-2.6.9 module problems In-Reply-To: <41911FD4.2060902@sun.com> Message-ID: References: <41911FD4.2060902@sun.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2249 Lines: 57 On Tue, 9 Nov 2004, Mike Waychison wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > linux-os wrote: >> >> I have a memory-test procedure that tests >> memory on a board, accessed via the PCI bus. >> There is a lot of RAM and it's bank-switched >> into some 64k windows so it takes a lot of >> time to test, about 60 seconds. >> >> This is in a module, therefore inside the kernel. >> When it is invoked via an ioctl() call, the >> kernel is frozen for the whole test-time. The >> test procedure does not use any spin-locks nor >> does it even use any semaphores. It just does a >> bunch of read/write operations over the PCI/Bus. >> >> I thought that I could enable the preemptible- >> kernel option and the machine would then respond >> normally. Not so. Even with 4 CPUs, when one >> ioctl() is busy in the kernel, nothing else >> happens until its done. Even keyboard activity >> is gone, no Caps Lock and no Num Lock, no `ping` >> response over the network. However, the machine >> comes back to life when the memory-test is done. >> >> This is kernel version 2.6.9. Is it possible that >> somebody left on the BKL when calling a module >> ioctl() on this version? If not, what do I do >> to be able to execute a time-consuming procedure >> from inside the kernel? Do I break it up into >> sections and execute schedule() periodically >> (temporary work-around --works)?? >> > > The BKL has always been grabbed across ioctls. Drop the lock when you > enter your f_op->ioctl call and grab it again open completion. > Hmmm. I get 'scheduling while atomic' screaming across the screen! There are no atomic operations in my ioctl functions so I don't know what its complaining about. I think I shouldn't have tried to do anything with BKL because I (my task) doesn't own it. Cheers, Dick Johnson Penguin : Linux version 2.6.9 on an i686 machine (5537.79 BogoMips). Notice : All mail here is now cached for review by John Ashcroft. 98.36% of all statistics are fiction. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/