Re: Change in default vm_dirty_ratio

Jens Axboe
2007-06-20T09:14:51Z

On Wed, Jun 20 2007, Andrew Morton wrote:
> Perhaps our queues are too long - if the VFS _does_ back off, it'll take
> some time for that to have an effect.
>
> Perhaps the fact that the queue size knows nothing about the _size_ of the
> requests in the queue is a problem.

It's complicated, the size may not matter a lot. 128 sequential 512kb IO
may complete faster than 128 random 4kb IO's.

> Back away even further here.
>
> What user-visible problem(s) are we attemping to fix?

I'd like innocent-app-doing-little-write-or-fsync not being stalled by
big-bad-app-doing-lots-of-dirtying.

--
Jens Axboe