> -----Original Message----- > From: Shrikanth Hegde <sshegde@xxxxxxxxxxxxx> > Sent: Tuesday, January 7, 2025 5:10 AM > To: Robert Joslyn <robert_joslyn@xxxxxxxxxx> > Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-rt-users@xxxxxxxxxxxxxxx; > tglx@xxxxxxxxxxxxx; rostedt@xxxxxxxxxxx; Sebastian Andrzej Siewior > <bigeasy@xxxxxxxxxxxxx> > Subject: Re: [PATCH] powerpc: Allow scheduling of IRQ with PREEMPT_RT > > [Caution - External] > > On 1/7/25 17:26, Sebastian Andrzej Siewior wrote: > > On 2024-12-26 11:12:38 [-0800], Robert Joslyn wrote: > >> This branch is needed to allow preemptible IRQs to be scheduled, > >> otherwise the kernel hangs during boot on my e300 based platforms. > >> This branch is needed for both CONFIG_PREEMPT and > CONFIG_PREEMPT_RT, > > Hi Robert. > > Are you running with preempt=full or enabled preempt_rt ? > rt is yet to be supported on powerpc. are you having it enabled out of tree? I'm running PREEMPT_RT using the out of tree patches on 6.6.58-rt45: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git/ I haven't tried using the mainline kernel, since as you said, it doesn't have powerpc support for PREEMPT_RT yet. > > Also, I have sent out patch to enable dynamic preemption. It uses > preempt_model_preemptible. > I think it should work for you as well. If you could give that a try and ensure it > works, it would be great. > https://urldefense.com/v3/__https://lore.kernel.org/all/20250106051919.5 > 5020-2- > sshegde@xxxxxxxxxxxxx/__;!!O7uE89YCNVw!IDeomstGeuiEZi9FmLHH8C2xo > PPo_ewL- > k2kiQ9CmVID35U4J_v3Dkafjo3RnS9ygPoUZWwyyp91SP2euRkKArk$ Does the dynamic preemption support let me enable the same functionality as PREEMPT_RT with the out of tree patches? I can test it out either way. Thanks, Robert
