From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A75A0C49EA6 for ; Thu, 24 Jun 2021 14:40:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91A596135C for ; Thu, 24 Jun 2021 14:40:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232378AbhFXOnI (ORCPT ); Thu, 24 Jun 2021 10:43:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:42296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232355AbhFXOnB (ORCPT ); Thu, 24 Jun 2021 10:43:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4A490613DA; Thu, 24 Jun 2021 14:40:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1624545641; bh=8Q/siINOJ+SbEMrV41GPkA6KGpvNdDIcQcpvV5TfjzA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MdKVAUxXXPbbdvo84gc7YYjWwkTuruINJ/BaLVXFBVrVgCepQr61eJaVJCPSgv7b6 eqCBhvGUDRD+bjE93n3LcvCaEPRWWm+zmM+uEEat5AIhOeR66D1/dodV5zryjqVRLV ePQzzQ87otbVs7LfIdJfiVFg1r7sG4Pdv614bKPw= Date: Thu, 24 Jun 2021 16:40:38 +0200 From: Greg KH To: Manivannan Sadhasivam Cc: hemantk@codeaurora.org, bbhatt@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, loic.poulain@linaro.org Subject: Re: [PATCH 6/8] bus: mhi: core: Add support for processing priority of event ring Message-ID: References: <20210621161616.77524-1-manivannan.sadhasivam@linaro.org> <20210621161616.77524-7-manivannan.sadhasivam@linaro.org> <20210624142453.GB6108@workstation> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210624142453.GB6108@workstation> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 24, 2021 at 07:54:53PM +0530, Manivannan Sadhasivam wrote: > On Thu, Jun 24, 2021 at 03:53:33PM +0200, Greg KH wrote: > > On Mon, Jun 21, 2021 at 09:46:14PM +0530, Manivannan Sadhasivam wrote: > > > From: Hemant Kumar > > > > > > Event ring priorities are currently set to 1 and are unused. > > > Default processing priority for event rings is set to regular > > > tasklet. Controllers can choose to use high priority tasklet > > > scheduling for certain event rings critical for processing such > > > as ones transporting control information if they wish to avoid > > > system scheduling delays for those packets. In order to support > > > these use cases, allow controllers to set event ring priority to > > > high. > > > > > > Signed-off-by: Hemant Kumar > > > Signed-off-by: Bhaumik Bhatt > > > Reviewed-by: Manivannan Sadhasivam > > > Link: https://lore.kernel.org/r/1624053903-24653-2-git-send-email-bbhatt@codeaurora.org > > > Signed-off-by: Manivannan Sadhasivam > > > --- > > > drivers/bus/mhi/core/init.c | 3 +-- > > > drivers/bus/mhi/core/main.c | 9 +++++++-- > > > include/linux/mhi.h | 2 +- > > > 3 files changed, 9 insertions(+), 5 deletions(-) > > > > > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c > > > index c81b377fca8f..444676034bf0 100644 > > > --- a/drivers/bus/mhi/core/init.c > > > +++ b/drivers/bus/mhi/core/init.c > > > @@ -673,8 +673,7 @@ static int parse_ev_cfg(struct mhi_controller *mhi_cntrl, > > > &mhi_cntrl->mhi_chan[mhi_event->chan]; > > > } > > > > > > - /* Priority is fixed to 1 for now */ > > > - mhi_event->priority = 1; > > > + mhi_event->priority = event_cfg->priority; > > > > > > mhi_event->db_cfg.brstmode = event_cfg->mode; > > > if (MHI_INVALID_BRSTMODE(mhi_event->db_cfg.brstmode)) > > > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c > > > index 8ac73f9e92a6..3775c77dec63 100644 > > > --- a/drivers/bus/mhi/core/main.c > > > +++ b/drivers/bus/mhi/core/main.c > > > @@ -454,10 +454,15 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev) > > > > > > if (mhi_dev) > > > mhi_notify(mhi_dev, MHI_CB_PENDING_DATA); > > > - } else { > > > - tasklet_schedule(&mhi_event->task); > > > + > > > + return IRQ_HANDLED; > > > } > > > > > > + if (!mhi_event->priority) > > > + tasklet_hi_schedule(&mhi_event->task); > > > + else > > > + tasklet_schedule(&mhi_event->task); > > > + > > > return IRQ_HANDLED; > > > } > > > > > > diff --git a/include/linux/mhi.h b/include/linux/mhi.h > > > index 86cea5256e3c..bf23c213429c 100644 > > > --- a/include/linux/mhi.h > > > +++ b/include/linux/mhi.h > > > @@ -250,7 +250,7 @@ struct mhi_channel_config { > > > * @irq_moderation_ms: Delay irq for additional events to be aggregated > > > * @irq: IRQ associated with this ring > > > * @channel: Dedicated channel number. U32_MAX indicates a non-dedicated ring > > > - * @priority: Priority of this ring. Use 1 for now > > > + * @priority: Processing priority of this ring. 0 is high and 1 is regular > > > > Why is 0 high and 1 low? Does that feel backwards? > > > > That's because, "1" was used from the beginning by the controller drivers > as the regular priority. And I thought of using "0" as high priority so > that we can leave the controller drivers unmodified. There's no problem modifying everyone, how much work is that? > > Shouldn't this be a boolean, or if not, an enumerated type so that > > people can read the code over time? > > > > Bhaumik proposed an enum but I wanted 0/1 so that the controller drivers > can be untouched. Also, I don't see any immediate requirement for other > priorities. > > Will make it a bool then. Rename it when you change it so that you know you catch all existing users. thanks, greg k-h