Re: [PATCH v3 3/3] genirq: reimplement exit_irq_thread() hook viatask_work_queue()

From: Thomas Gleixner
Date: Fri Apr 13 2012 - 05:42:10 EST


On Thu, 12 Apr 2012, Oleg Nesterov wrote:

> exit_irq_thread() and task->irq_thread are needed to handle
> the unexpected (and unlikely) exit of irq-thread.
>
> We can use task_work instead and make this all private to
> kernel/irq/manage.c, simplification plus micro-optimization.
>
> 1. rename exit_irq_thread() to irq_thread_dtor(), make it
> static, and move it up before irq_thread().
>
> 2. change irq_thread() to do task_queue_work(irq_thread_dtor)
> at the start and task_work_cancel() before return.
>
> tracehook_notify_resume() can never play with kthreads,
> only do_exit()->exit_task_work() can call the callback
> and this is what we want.
>
> 3. remove task_struct->irq_thread and the special hook
> in do_exit().
>
> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> ---
> include/linux/interrupt.h | 4 --
> include/linux/sched.h | 10 +-----
> kernel/exit.c | 2 -
> kernel/irq/manage.c | 69 +++++++++++++++++++++-----------------------
> 4 files changed, 35 insertions(+), 50 deletions(-)

Nice cleanup.

Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
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