From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 2/5] scsi: improved eh timeout handler Date: Thu, 07 Nov 2013 07:45:27 +0100 Message-ID: <527B3707.9060202@suse.de> References: <1383635145-112651-1-git-send-email-hare@suse.de> <1383635145-112651-3-git-send-email-hare@suse.de> <527944BF.9000507@cs.wisc.edu> <5279E64E.8040005@suse.de> <527A7AF7.10809@cs.wisc.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from cantor2.suse.de ([195.135.220.15]:43991 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751676Ab3KGGp3 (ORCPT ); Thu, 7 Nov 2013 01:45:29 -0500 In-Reply-To: <527A7AF7.10809@cs.wisc.edu> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Mike Christie Cc: James Bottomley , Christoph Hellwig , linux-scsi@vger.kernel.org, Ren Mingxin , Joern Engel , James Smart On 11/06/2013 06:23 PM, Mike Christie wrote: > On 11/05/2013 10:48 PM, Hannes Reinecke wrote: >> On 11/05/2013 08:19 PM, Mike Christie wrote: >>> On 11/04/2013 11:05 PM, Hannes Reinecke wrote: >>>> + >>>> + scmd->eh_eflags |=3D SCSI_EH_ABORT_SCHEDULED; >>>> + SCSI_LOG_ERROR_RECOVERY(3, >>>> + scmd_printk(KERN_INFO, scmd, >>>> + "scmd %p abort scheduled\n", scmd)); >>>> + schedule_delayed_work(&scmd->abort_work, HZ / 100); >>>> + return SUCCESS; >>>> +} >>> >>> Do we want to use our own workqueue_struct with WQ_MEM_RECLAIM set? >>> >> Errm. Yes, why? >> >> I must admit I'm not _that_ familiar with workqueues ... >> Care to explain? >> >=20 > We all share the above workqueue_structs pool of threads, so if we ge= t > stuck behind code doing GFP_KERNEL allocs that end up needing to writ= e > data to the disk we are now trying to aborts on, then we could get > stuck. With WQ_MEM_RECLAIM, we have our own backup thread that gets > created at workqueue_struct create time which can get used in cases l= ike > that so we can always make forward progress. >=20 Ah. Right. Yes, that makes sense. I guess I'll have to redo the patches _yet again_. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: J. Hawn, J. Guild, F. Imend=F6rffer, HRB 16746 (AG N=FCrnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html