From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934268AbaKMWQp (ORCPT ); Thu, 13 Nov 2014 17:16:45 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:52861 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S933065AbaKMWQo (ORCPT ); Thu, 13 Nov 2014 17:16:44 -0500 From: "Rafael J. Wysocki" To: "Zheng, Lv" Cc: "Wysocki, Rafael J" , "Brown, Len" , Lv Zheng , "linux-kernel@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "Andi Kleen (ak@linux.intel.com)" Subject: Re: [PATCH 5/6] ACPI/EC: Cleanup QR_SC command processing by adding a kernel thread to poll EC events. Date: Thu, 13 Nov 2014 23:37:41 +0100 Message-ID: <1586902.iI2oFdt4zk@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.16.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1AE640813FDE7649BE1B193DEA596E88026A0737@SHSMSX101.ccr.corp.intel.com> References: <1961414.bGx3EdA0yT@vostro.rjw.lan> <1AE640813FDE7649BE1B193DEA596E88026A0737@SHSMSX101.ccr.corp.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday, November 13, 2014 02:52:03 AM Zheng, Lv wrote: > Hi, Rafael > > > From: Rafael J. Wysocki [mailto:rjw@rjwysocki.net] > > Sent: Thursday, November 13, 2014 10:59 AM > > > > On Thursday, November 13, 2014 02:31:08 AM Zheng, Lv wrote: > > > Hi, Rafael > > > > > > > From: Rafael J. Wysocki [mailto:rjw@rjwysocki.net] > > > > Sent: Wednesday, November 12, 2014 9:17 AM > > > > [cut] > > > > > > > + > > > > > +static int ec_create_event_poller(struct acpi_ec *ec) > > > > > +{ > > > > > + struct task_struct *t; > > > > > + > > > > > + t = kthread_run(acpi_ec_event_poller, ec, "ec/gpe-%lu", ec->gpe); > > > > > > > > Does it have to be a kernel thread? > > > > > > > > What about using a workqueue instead? > > > > > > Actually I just want to use threaded IRQ here in response to Andi Kleen's comment. > > > If acpi_irq is registered as threaded IRQ, then acpi_ec_event_poller() will be the > > > callback from it. > > > > How so? > > > > > Since ACPICA is not ready for threaded IRQ currently, we cannot proceed at this point. > > > So I copied the threaded IRQ code from kernel/irq/manage.c here to prepare threaded IRQ logics. > > > > Oh dear, no. > > > > This isn't the way forward here. > > > > > Using a separate work queue, we didn't decrease the kernel thread count. > > > > Why does that matter at all? > > > > > And the code written for the work item cannot be derived when things are > > > switched to the threaded IRQ. > > > So I used kthread here. > > > > Please use a workqueue instead. If/when we need to switch over to threaded > > IRQs, we'll do the work then. For now, let's not complicate things more > > than necessary. > > It seems we need the thread because we will move polling code from ec_poll() to acpi_ec_event_poller(). > This will happen right after these cleanups. > That's the threaded IRQ logic - IRQ is polled in the thread. > We cannot achieve this using work queue. OK In that case I'm not going to apply this patch, because it is not a cleanup. It doesn't belong to this series, but to the series that will move the polling code. Does patch [6/6] depend on [5/6]? -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.