From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: [PATCH 1/1] be2iscsi: Enabling MSIX and mcc_rings V2 Date: Wed, 21 Oct 2009 13:20:34 -0500 Message-ID: <4ADF50F2.80800@cs.wisc.edu> References: <20091021181043.71aff47a@mailhost.serverengines.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from sabe.cs.wisc.edu ([128.105.6.20]:47218 "EHLO sabe.cs.wisc.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751185AbZJUSUg (ORCPT ); Wed, 21 Oct 2009 14:20:36 -0400 In-Reply-To: <20091021181043.71aff47a@mailhost.serverengines.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jayamohan Kalickal Cc: linux-scsi@vger.kernel.org Jayamohan Kalickal wrote: > _____ > From: Mike Christie [mailto:michaelc@cs.wisc.edu] > To: Jayamohan Kalickal [mailto:jayamohank@serverengines.com] > Cc: linux-scsi@vger.kernel.org > Sent: Wed, 21 Oct 2009 10:19:06 -0700 > Subject: Re: [PATCH 1/1] be2iscsi: Enabling MSIX and mcc_rings V2 > > Jayamohan Kallickal wrote: >> This patch >> >> 1) Turns on msix >> 2) Adds mcc_ring support for sending FW commands >> 3) Adds Support for Ring Mode of WRB Posting >> 4) Adds sysfs for FW commands > > > I think msix should be a separate patch from the fw command one, and the > ring mode changes could probably be in a separate patch too. > > Will Do that > >> + >> +static void beiscsi_async_link_state_process(struct beiscsi_hba *phba, >> + struct be_async_event_link_state *evt) >> +{ >> + switch (evt->port_link_status) { >> + case ASYNC_EVENT_LINK_DOWN: >> + SE_DEBUG(DBG_LVL_1, "Link Down on Physical Port %d \n", >> + evt->physical_port); >> + break; > > > When you get a link down, does it cause the fw do start iscsi recovery > or does it send the driver a notification that a command is failed due > to the link down. For example if we were doing erl0, and the link is > gone, would the fw return some error for each command? > > > For link down maybe you want to fire a iscsi conn error for each > session/connection on the port, so that way the iscsi layer can block > the sessions and start recovery. > > The FW will report LINKDOWN event almost immediately when the event is noticed. > > Some thoughts on the implementation > > 1) Rather than immediately shutting down all the sessions , wait for a predetermined > time ,say, 10 Secs(if the user has pulled the cable and is connecting it back ,for eg, to > connect to a different port on the switch etc). Since IO's will not exceed the Queue Depth, this should be fine. However, for MPIO, we may need to load with a parameter (or something better) so that we will fail immediately and IO's can be switched over to other port faster. > We have a timer it is called the replacement_timeout/recovery_timeout. This will determine how fast we fail cmds upwards when handling these type of errors. When you call iscsi_session_failure or iscsi_conn_faulure it will start the timer. Today, users will set this very short for MPIO setups and very high for something else like root on iscsi. > 2) Since this function to shutdown sessions will be used by many drivers , shall we make this > part of libiscsi. Can do this. > Yes, libiscsi is best. See bnx2i's iscsi_host_for_each_session+iscsi_session_failure use. > > 2) Since this is > > 2) > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > > ___________________________________________________________________________________ > This message, together with any attachment(s), contains confidential and proprietary information of > ServerEngines Corporation and is intended only for the designated recipient(s) named above. Any unauthorized > review, printing, retention, copying, disclosure or distribution is strictly prohibited. If you are not the > intended recipient of this message, please immediately advise the sender by reply email message and > delete all copies of this message and any attachment(s). Thank you. > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html