Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755614Ab0GJOwK (ORCPT ); Sat, 10 Jul 2010 10:52:10 -0400 Received: from mail-gy0-f174.google.com ([209.85.160.174]:60686 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753074Ab0GJOwH convert rfc822-to-8bit (ORCPT ); Sat, 10 Jul 2010 10:52:07 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=haEB0yMGg7Ayi3tg+nLmMR6WSgLzfKiu4OfASwFbYR1IjMW6eextoVENyuPySKdNSB YUqK9gLgMe3XxxJ+SXJcQ3iGXi8ES+Af2XwaL8s4HaqZhWFzvLqQ4AUtDKIyasCE9ZWJ +QhmgBGRoQh45FfWWK7y2Kslw/zLHi8vowbB0= MIME-Version: 1.0 In-Reply-To: References: Date: Sat, 10 Jul 2010 15:52:04 +0100 Message-ID: Subject: Re: [2.6.35-rc3] select useful number of entries for DMA debugging... From: Daniel J Blueman To: Linus Torvalds Cc: Linux Kernel Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1574 Lines: 34 On 9 July 2010 22:33, Linus Torvalds wrote: > On Mon, Jul 5, 2010 at 1:35 AM, Daniel J Blueman > wrote: >> When booting 2.6.35-rc3 on some different x86 boxes with DMA debugging >> enabled, I've consistently seen it exhaust the allocated entries during >> boot, giving 'DMA-API: debugging out of memory - disabling'. >> >> Increase number of entries to allow DMA debugging again. > > Rather than increase the default that gets allocated whenever anybody > enables the DMA debugging, I'd really prefer to see people use the > kernel command line option if they run out. After all, it's a (pretty > esoteric) debug option, and the number of required entries depends on > machine configuration. I'd rather not make the default cover a huge > number, when you could just add > > ? dma_debug_entries=65536 > > on the kernel boot command line instead for machines that want/need it.. That said, I am seeing the DMA pool exhaust on a single socket Core i5 system with Intel graphics and no other adapters - seems like a fairly common case. If eg 25% of developers will be using similar to this, maybe it's good to make DMA debugging less immediately esoteric? On the other hand, I would immediately agree if the exhaustion occurred on an atypical setup. -- Daniel J Blueman -- 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/