Re: [PATCH v3 10/12] x86/mm: Move flush_tlb_info back to the stack

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2026-03-19 21:41:28 [+0800], Chuyi Zhou wrote:
> Hi Sebastian,
Hi,

> IIUC, you mean something like the following?

basically yes. Later you might want to add a static_branch to
can_inline_cpumask() instead the check you have now. The value to
cpumask_size() should be assigned once the number of possible CPUs is
known and never change.

> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 5a5d3dbc9cdf..4222114cd34c 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -927,6 +927,8 @@ struct task_struct {
>          unsigned short                  migration_disabled;
>          unsigned short                  migration_flags;
> 
> +       cpumask_t                       *ipi_cpus;

This is probably not the best spot to stuff it. You will have a 4byte
gap there. After user_cpus_ptr would be okay from alignment but I am not
sure if something else shifts too much.

> +
>   #ifdef CONFIG_PREEMPT_RCU
>          int                             rcu_read_lock_nesting;
>          union rcu_special               rcu_read_unlock_special;

Sebastian