Re: RFC: dirty_ratio back to 40%

From: Jan Kara
Date: Fri May 21 2010 - 12:00:56 EST

On Fri 21-05-10 10:11:59, KOSAKI Motohiro wrote:
> > > So, I'd prefer to restore the default rather than both Redhat and SUSE apply exactly
> > > same distro specific patch. because we can easily imazine other users will face the same
> > > issue in the future.
> >
> > On desktop systems the low dirty limits help maintain interactive feel.
> > Users expect applications that are saving data to be slow. They do not
> > like it when every application in the system randomly comes to a halt
> > because of one program stuffing data up to the dirty limit.
> really?
> Do you mean our per-task dirty limit wouldn't works?
> If so, I think we need fix it. IOW sane per-task dirty limitation seems
> independent issue from per-system dirty limit.
Well, I don't know about any per-task dirty limits. What function
implements them? Any application that dirties a single page can be caught
and forced to call balance_dirty_pages() and do writeback.
But generally what we observe on a desktop with lots of dirty memory is
that application needs to allocate memory (either private one or for page
cache) and that triggers direct reclaim so the allocation takes a long
time to finish and thus the application is sluggish...

Jan Kara <jack@xxxxxxx>
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at