Re: [RFC PATCH v3 15/18] mm: Add balance_dirty_pages_ratelimited_async() function

[Christoph Hellwig <hch@infradead.org>]

> +static int balance_dirty_pages_ratelimited_flags(struct address_space *mapping,
> +						bool no_wait)
>  {

This doesn't actully take flags, but a single boolean argument.  So
either it needs a new name, or we actually pass a descriptiv flag.

> +/**
> + * balance_dirty_pages_ratelimited_async - balance dirty memory state
> + * @mapping: address_space which was dirtied
> + *
> + * Processes which are dirtying memory should call in here once for each page
> + * which was newly dirtied.  The function will periodically check the system's
> + * dirty state and will initiate writeback if needed.
> + *
> + * Once we're over the dirty memory limit we decrease the ratelimiting
> + * by a lot, to prevent individual processes from overshooting the limit
> + * by (ratelimit_pages) each.
> + *
> + * This is the async version of the API. It only checks if it is required to
> + * balance dirty pages. In case it needs to balance dirty pages, it returns
> + * -EAGAIN.
> + */
> +int  balance_dirty_pages_ratelimited_async(struct address_space *mapping)
> +{
> +	return balance_dirty_pages_ratelimited_flags(mapping, true);
> +}
> +EXPORT_SYMBOL(balance_dirty_pages_ratelimited_async);

I'd much rather export the underlying
balance_dirty_pages_ratelimited_flags helper than adding a pointless
wrapper here.  And as long as only iomap is supported there is no need
to export it at all.