On Wed, 04 Nov 2026 16:45:55 +0000,
"Aneesh Kumar K.V (Arm)" <[email protected]> wrote:
>
> VPE L1 tables are allocated from the CPU-starting callback, where sleeping is
> not allowed. Remove the page allocation from this atomic path.
>
> Use a blocking allocation for the boot CPU and record the resulting table
> order. Allocate a page of that order from the sleepable CPU hotplug prepare
> stage for each secondary CPU. Consume the preallocated page only when the CPU
> cannot inherit an existing redistributor or ITS table.
>
> Reclaim unused preallocations after the CPU reaches the online state, and from
> the prepare-state teardown when CPU bring-up aborts.
No. The way to do it is to move the ITS probing out of the
non-sleepable CPU hotplug path.
I proposed a potential hack at [1] (which I find far more palatable
than this proposal), but the real fix is to probe the ITSs as
devices. Putting even more ugly hacks on top of the existing PoS
driver is definitely not an acceptable outcome.
M.
[1] https://lore.kernel.org/all/[email protected]/
--
Without deviation from the norm, progress is not possible.
