Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754185AbbFSQM4 (ORCPT ); Fri, 19 Jun 2015 12:12:56 -0400 Received: from mga11.intel.com ([192.55.52.93]:15163 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752303AbbFSQMt (ORCPT ); Fri, 19 Jun 2015 12:12:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,644,1427785200"; d="scan'208";a="749708249" Message-ID: <55843F79.4000606@linux.intel.com> Date: Sat, 20 Jun 2015 00:12:41 +0800 From: Jiang Liu Organization: Intel User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Thomas Gleixner , Sergey Senozhatsky CC: Borislav Petkov , linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: Re: [-next] !irqd_can_balance() WARNINGs at irq_move_masked_irq() References: <20150619071123.GA511@swordfish> <55843EC9.9000401@linux.intel.com> In-Reply-To: <55843EC9.9000401@linux.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1438 Lines: 33 [...] >> Something in the kernel (not yet clear what) tries to move the hpet >> irq 0 by calling irq_set_affinity(). That's an kernel internal >> interface which does not check whether the NO BALANCE flag is set for >> the irq. So the call runs and triggers the move from next interrupt >> machinery which ends up calling irq_move_masked_irq() and that trips >> over the flag and yells. >> >> That's why I changed the WARN to a pr_warn() because we already know >> the call stack. >> >> So the core behaviour is inconsistent. We let the caller of >> irq_set_affinity() succeed and yell later because we think it's wrong. >> >> I'm pretty sure that we must drop the check for NO BALANCE in >> irq_move_masked_irq() and only check for the per_cpu bit, but at the >> same time I really want to know where that call to irq_set_affinity(irq0) >> is coming from. >> >> Can you please collect the output of /proc/timer_list for the previous >> patch and then replace the previous patch with the one below and >> gather all the data again? > > Hi Thomas, > Maybe it's caused by the hpet driver itself? > irq_set_affinity() may set the IRQD_SETAFFINITY_PENDING flag, > thus triggering the warning. And the usage pattern seems reasonable, the IRQF_NOBALANCING flag means nobody may change the affinity except myself:) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/