Re: [PATCH v2] hugetlbfs: Disable softIRQ when taking hugetlb_lock

From: Andi Kleen
Date: Thu Dec 12 2019 - 16:32:42 EST


Davidlohr Bueso <dave@xxxxxxxxxxxx> writes:
> +void free_huge_page(struct page *page)
> +{
> + struct hugetlb_free_page_work work;
> +
> + work.page = page;
> + INIT_WORK_ONSTACK(&work.work, free_huge_page_workfn);
> + queue_work(hugetlb_free_page_wq, &work.work);
> +
> + /*
> + * Wait until free_huge_page is done.
> + */
> + flush_work(&work.work);
> + destroy_work_on_stack(&work.work);

Does flushing really work in softirq context?

Anyways, waiting seems inefficient over fire'n'forget

You'll need a per cpu pre allocated work item and a queue.
Then take a lock on the the queue and link the page into
it and trigger the work item if it's not already pending.

And add a in_interrupt() check of course.


-Andi