Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267460AbUIJPRY (ORCPT ); Fri, 10 Sep 2004 11:17:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266793AbUIJPRY (ORCPT ); Fri, 10 Sep 2004 11:17:24 -0400 Received: from jade.spiritone.com ([216.99.193.136]:65408 "EHLO jade.spiritone.com") by vger.kernel.org with ESMTP id S267460AbUIJPRH (ORCPT ); Fri, 10 Sep 2004 11:17:07 -0400 Date: Fri, 10 Sep 2004 08:16:39 -0700 From: "Martin J. Bligh" To: Hugh Dickins cc: Andrea Arcangeli , Alan Cox , arjanv@redhat.com, Chris Wedgwood , LKML , Christoph Hellwig Subject: Re: [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option Message-ID: <596720000.1094829398@[10.10.2.4]> In-Reply-To: References: X-Mailer: Mulberry/2.2.1 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1677 Lines: 39 --Hugh Dickins wrote (on Friday, September 10, 2004 16:07:21 +0100): > On Fri, 10 Sep 2004, Martin J. Bligh wrote: >> >> I agree about killing anything but 4K stacks though - having the single >> page is very compelling - not only can we allocate it easier, but we can >> also use cache-hot pages from the hot list. > > I think we all agree that's a promising future, and a good discipline. > But I'm not the only one to doubt we're there yet. > > Chris's patch seems eminently sensible to me. Why should having separate > interrupt stack depend on whether you're configured for 4K or 8K stacks? > > Wasn't Andrea worried, a couple of months back, about nested interrupts > overflowing the 4K interrupt stack? He was trying to work out how to > have an 8K interrupt stack even with the 4K task stack, proposed thread > info at both top and bottom of stack; but his "current" still looked to > me like it'd be significantly more costly than the present one. > > I'm all for Chris's patch. I have no problem with 8K interrupt stacks - they're static, and per CPU, so I doubt anyone cares ... But 8K task stacks + interrupt stacks seems to just encourage bloat to me. And if you agree that we're going to 4K, I don't really see the point - if people are really hitting problems (I don't recall any actual reports) then I'd prefer to see them fixed properly by poking the fat bloater with a big pin. M. - 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/