Re: Change in default vm_dirty_ratio

[Jens Axboe]

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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/