Re: [PATCH] cgroup: Move cgrp_dead_ task+iwork into its own struct

["Michal Koutný" <mkoutny@suse.com>]

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On Fri, Sep 11, 2026 at 12:19:00PM +0200, Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:
> cgrp_dead_tasks and cgrp_dead_tasks_iwork are independent per-CPU
> variables and are independently accessed via a this_cpu_ptr().
> 
> Having a custom struct with those two members makes it possible to have
> only one per-CPU accessor and access the second member via an offset.
> This makes the code a bit more compact and is micro-optimization.
> 
> Besides that, it allows cgrp_dead_tasks_iwork_fn() to access the list
> pointer via the passed iwork pointer. This not only eliminates the
> this_cpu_ptr() but also makes it possible to be invoked on a different
> CPU. This does not happen as of today but might if I can flush the
> irq_work items from another CPU during CPU-hotplug events.
> 
> Create struct cgroup_dead with the per-CPU variables as members. Access
> the struct with a per-CPU accessor and use the cointer_of() in the
> irq_work callback.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>  kernel/cgroup/cgroup.c | 23 +++++++++++++++--------
>  1 file changed, 15 insertions(+), 8 deletions(-)

Acked-by: Michal Koutný <mkoutny@suse.com>

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