Re: [PATCH v8 03/14] mm: Add balance_dirty_pages_ratelimited_flags() function

[Matthew Wilcox <willy@infradead.org>]

On Wed, Jun 08, 2022 at 10:17:30AM -0700, Stefan Roesch wrote:
> -/**
> - * balance_dirty_pages_ratelimited - 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.
> - */
> -void balance_dirty_pages_ratelimited(struct address_space *mapping)
> +int balance_dirty_pages_ratelimited_flags(struct address_space *mapping,
> +					unsigned int flags)

I'm distressed to see no documentation for
balance_dirty_pages_ratelimited_flags().  I see it got moved down to
balance_dirty_pages_ratelimited(), but this function is externally
visible and needs (at the very least) something like this:

/**
 * balance_dirty_pages_ratelimited_flags - Balance dirty memory state.
 * @mapping: address_space which was dirtied.
 * @flags: BDP flags.
 *
 * See balance_dirty_pages_ratelimited() for details.
 *
 * Return: If @flags contains BDP_ASYNC, it may return -EAGAIN to
 * indicate that memory is out of balance and the caller must wait
 * for I/O to complete.  Otherwise, it will return 0 to indicate
 * that either memory was already in balance, or it was able to sleep
 * until the amount of dirty memory returned to balance.
 */