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

Stefan Roesch
2022-05-20T18:30:28Z

On 5/19/22 1:29 AM, Christoph Hellwig wrote:
>> +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.
>

Thats what I originally had. I'm reverting back to it.