From mboxrd@z Thu Jan 1 00:00:00 1970 From: lina.iyer@linaro.org (Lina Iyer) Date: Fri, 10 Oct 2014 09:11:06 -0600 Subject: [PATCH v3 3/4] irq: Allow multiple clients to register for irq affinity notification In-Reply-To: References: <1409170479-29955-1-git-send-email-lina.iyer@linaro.org> <1409170479-29955-4-git-send-email-lina.iyer@linaro.org> <20140902184305.GB91995@ilina-mac.local> <20140925155027.GG1004@ilina-mac.local> Message-ID: <20141010151106.GC2128@ilina-mac.qualcomm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Oct 08 2014 at 09:03 -0600, Thomas Gleixner wrote: >On Thu, 25 Sep 2014, Lina Iyer wrote: >> > How would a general "keep track of the targets of all interrupts in >> > the system" mechanism make use of this? >> Sorry, I do not understand your question. >> PM QoS is only interested in the IRQs specified in the QoS request. If >> there are no requests that need to be associated with an IRQ, then PM >> QoS will not register for an affinity change notification. > >Right, and I really hate the whole per irq notifier. It's a rats nest >of life time issues and other problems. > >It also does not tell you whether an irq is disabled, reenabled or >removed, which will change the qos constraints as well unless you >plaster all drivers with updates to qos for those cases. > >So what about adding a qos field to irq_data itself, have a function >to update it and let the irq core keep track of the per cpu irq >relevant qos constraints and provide an evaluation function or a >notifier for the PM/idle code? If that isnt intrusive in the IRQ core, then we can make it work for PM QoS. The issue that I am concerned is that, it might result in back and forth between IRQ and PM QoS frameworks. If that doesnt happen, then we are good with this approach. > >That's going to need some serious thought as well, but it should avoid >most of the nasty notifier and lifetime issue which the per irq >notifiers provide. Sure. I will look into this. > >Thoughts? Thank you. Lina > > > >