From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033528AbbKEQpM (ORCPT ); Thu, 5 Nov 2015 11:45:12 -0500 Received: from arroyo.ext.ti.com ([192.94.94.40]:58658 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032988AbbKEQpK (ORCPT ); Thu, 5 Nov 2015 11:45:10 -0500 Subject: Re: [v4.1.10-rt10][PATCH 1/2] genirq: introduce new generic_handle_irq_rt_wa() api To: Sebastian Andrzej Siewior , Thomas Gleixner References: <1446492626-24396-1-git-send-email-grygorii.strashko@ti.com> <1446492626-24396-2-git-send-email-grygorii.strashko@ti.com> <563906C5.8030801@ti.com> <56391694.3030105@linutronix.de> CC: , , Sekhar Nori From: Grygorii Strashko Message-ID: <563B8788.1090000@ti.com> Date: Thu, 5 Nov 2015 18:44:56 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <56391694.3030105@linutronix.de> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thomas, Sebastian, On 11/03/2015 10:18 PM, Sebastian Andrzej Siewior wrote: > On 11/03/2015 08:51 PM, Thomas Gleixner wrote: >>> where MAX_MSI_IRQS = 32 now, but potentially can be increased up to 256. >> >> And you really oversimplified the code above. The reality is: >> >> for (i = 0; i < MAX_MSI_CTRLS: i++) { >> u32 status = read_msi_ctrl(i); >> >> for_each_bit(status) >> handle_irq(); >> } >> >> So sure, the worst case here is MAX_MSI_CTRLS * 32, but if all >> possible 256 MSI interrupts are pending at the same time, you have >> other problems than that. > > With threaded interrupts we would have 256 invocations of > wake_up_process() so nothing should take ages. > Thanks a lot for your time and comments - I'll follow your recommendations and use IRQF_NO_THREAD. -- regards, -grygorii