Re: [PATCH 12/41] mm: add per-VMA lock and helper functions to control it

[Michal Hocko]

On Mon 09-01-23 12:53:07, Suren Baghdasaryan wrote:
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 5986817f393c..c026d75108b3 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -474,6 +474,7 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
>  		 */
>  		*new = data_race(*orig);
>  		INIT_LIST_HEAD(&new->anon_vma_chain);
> +		vma_init_lock(new);
>  		dup_anon_vma_name(orig, new);
>  	}
>  	return new;
> @@ -1145,6 +1146,9 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
>  	seqcount_init(&mm->write_protect_seq);
>  	mmap_init_lock(mm);
>  	INIT_LIST_HEAD(&mm->mmlist);
> +#ifdef CONFIG_PER_VMA_LOCK
> +	WRITE_ONCE(mm->mm_lock_seq, 0);
> +#endif

The mm shouldn't be visible so why WRITE_ONCE?

-- 
Michal Hocko
SUSE Labs