Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753117Ab3GXUmq (ORCPT ); Wed, 24 Jul 2013 16:42:46 -0400 Received: from mail-ea0-f176.google.com ([209.85.215.176]:63965 "EHLO mail-ea0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752418Ab3GXUmo convert rfc822-to-8bit (ORCPT ); Wed, 24 Jul 2013 16:42:44 -0400 MIME-Version: 1.0 X-Originating-IP: [188.120.142.218] In-Reply-To: <20130719221143.GG29404@logfs.org> References: <20130719220659.GF29404@logfs.org> <20130719221143.GG29404@logfs.org> From: Baruch Even Date: Wed, 24 Jul 2013 23:42:22 +0300 Message-ID: Subject: Re: [PATCH] mpt2sas: don't handle broadcast primitives To: =?UTF-8?Q?J=C3=B6rn_Engel?= Cc: Nagalakshmi Nandigama , Sreekanth Reddy , Support , "James E.J. Bottomley" , DL-MPTFusionLinux@lsi.com, linux-scsi , linux-kernel@vger.kernel.org, mit@purestorage.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1597 Lines: 33 On Sat, Jul 20, 2013 at 1:11 AM, Jörn Engel wrote: > On Fri, 19 July 2013 18:06:59 -0400, Jörn Engel wrote: >> >> The handling of broadcast primitives involves >> _scsih_block_io_all_device(), which does what the name implies. I have >> observed cases with >60s of blocking io on all devices, caused by a >> single bad device. The downsides of this code are obvious, while the >> upsides are more elusive. > > And since this patch looks more like an April fools joke: I have > gathered a few machine-months of testing, including tortures that > specifically stress the removed codepaths. This is a serious > submission and unless someone can show me a _very_ good reason for > keeping the deleted code, I would like to get it merged. This would seem to cause an IO pause through the host whenever there is a disk removal/insertion or SES (SAS expander) change which seems like a bad proposition indeed. The part of the work that this code seems to handle is that when such a change happens something needs to detect the dead IOs (f.ex. surprise disk removal) but I believe that the SAS HBA firmware will do that internally already so I do think this code is needless. The only thing I'd like not to lose is the actual notification and ability to log the fact that there was a broadcast notification on the SAS network. Baruch -- 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/