From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: [PATCH 23/24] advansys: Improve interrupt handler Date: Fri, 27 Jul 2007 11:36:13 -0600 Message-ID: <20070727173613.GN21219@parisc-linux.org> References: <20070727134038.GC21219@parisc-linux.org> <11855437542538-git-send-email-matthew@wil.cx> <46AA05ED.2060208@garzik.org> <20070727145336.GK21219@parisc-linux.org> <46AA07CC.9090004@garzik.org> <20070727150420.GL21219@parisc-linux.org> <46AA0B70.9060108@garzik.org> <20070727152520.GM21219@parisc-linux.org> <46AA150A.5090804@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from palinux.external.hp.com ([192.25.206.14]:56999 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932679AbXG0RgP (ORCPT ); Fri, 27 Jul 2007 13:36:15 -0400 Content-Disposition: inline In-Reply-To: <46AA150A.5090804@garzik.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jeff Garzik Cc: linux-scsi@vger.kernel.org On Fri, Jul 27, 2007 at 11:53:46AM -0400, Jeff Garzik wrote: > Matthew Wilcox wrote: > >I still say it's an improvement over scanning the list of scsi hosts > >looking for any that have work pending whenever any interrupt comes in. > > Having the kernel interrupt subsystem implement a loop for you is > completely utterly unusual, slow, silly, and likely to get broken when > people futz with the interrupt system core. It probably has edge cases > too, like screwing with the screaming interrupt detection code. > > The kernel interrupt subsystem is not meant to be abused in that way. I think what you're missing is: This isn't new. The advansys driver was *already* requesting the same interrupt twice for EISA boards. It's just that before, when an interrupt happened on the EISA board, it would scan all Scsi_Hosts twice, and now it scans this pair of boards once each. It may not be elegant, it may not be the best way, but it *is* a monotonic improvement. So please, calm down. -- "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."