Re: [PATCH] task_work: remove fifo ordering guarantee

[Oleg Nesterov]

On 08/29, Ingo Molnar wrote:
>
> So I'm wondering, is there any strong reason why we couldn't use a double linked
> list and still do FIFO and remove that silly linear list walking hack?

This will obviously enlarge callback_head, and it is often embedded.
But this is minor.

If we use a double linked list we can't do task_work_add() lockless.
So we will need another spinlock_t in task_struct. We can't use pi_lock.

Oleg.

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