From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Thumshirn Subject: Re: [PATCH 04/10] aacraid: Relinquish CPU during timeout wait Date: Wed, 27 Apr 2016 11:31:09 +0200 Message-ID: <20160427093109.GH2820@c203.arch.suse.de> References: <20160426062414.28402.69178.stgit@pmcuser-System-Product-Name> <20160426063126.28402.85984.stgit@pmcuser-System-Product-Name> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mx2.suse.de ([195.135.220.15]:39807 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752346AbcD0JbM (ORCPT ); Wed, 27 Apr 2016 05:31:12 -0400 Content-Disposition: inline In-Reply-To: <20160426063126.28402.85984.stgit@pmcuser-System-Product-Name> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Raghava Aditya Renukunta Cc: JBottomley@odin.com, linux-scsi@vger.kernel.org, martin.petersen@oracle.com, aacraid@pmc-sierra.com, gana.sridaran@microsemi.com, scott.benesh@microsemi.com, vishal.josemannanal@microsemi.com On Mon, Apr 25, 2016 at 11:31:26PM -0700, Raghava Aditya Renukunta wrot= e: > aac_fib_send has a special function case for initial commands during > driver initialization using wait < 0(pseudo sync mode). In this case, > the command does not sleep but rather spins checking for timeout.This > loop is calls cpu_relax() in an attempt to allow other processes/thre= ads > to use the CPU, but this function does not relinquish the CPU and so = the > command will hog the processor. This was observed in a KDUMP > "crashkernel" and that prevented the "command thread" (which is > responsible for completing the command from being timed out) from > starting because it could not get the CPU. >=20 > Fixed by replacing "cpu_relax()" call with "schedule()" > Cc: stable@vger.kernel.org >=20 > Signed-off-by: Raghava Aditya Renukunta Reviewed-by: Johannes Thumshirn --=20 Johannes Thumshirn Storage jthumshirn@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: Felix Imend=F6rffer, Jane Smithard, Graham Norton HRB 21284 (AG N=FCrnberg) Key fingerprint =3D EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850 -- 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