On Wed, 2 Oct 2019, Leonardo Bras wrote:
> +
> +inline unsigned long __begin_lockless_pgtbl_walk(struct mm_struct *mm,
> + bool disable_irq)
> +{
> + unsigned long irq_mask = 0;
> +
> + if (IS_ENABLED(CONFIG_LOCKLESS_PAGE_TABLE_WALK_TRACKING))
> + atomic_inc(&mm->lockless_pgtbl_walkers);
> +
You are creating contention on a single exclusive cacheline. Doesnt this
defeat the whole purpose of the lockless page table walk? Use mmap_sem or
so should cause the same performance regression?
