lkml.org 
[lkml]   [2007]   [Apr]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 10/10] mm: per device dirty threshold
From
Date
> > No, we _start_ writeback for 1.5*ratelimit_pages pages, but do not
> > wait for those writebacks to finish.
> >
> > So for a slow device and a fast writer, dirty+writeback can indeed
> > increase beyond the dirty threshold.
> >
>
> Nope, try it.
>
> If a process dirties 1000 pages it'll then go into balance_dirty_pages()
> and start writeback against 1,500 pages. When we hit dirty_ratio that
> process will be required to write back 1,500 pages for each eight pages
> which it dirtied. We'll quickly reach the stage where there are no longer
> 1,500 pages to be written back and the process will block in
> balance_dirty_pages() until the dirty+writeback level subsides.

OK. I was confused by this:

static long ratelimit_pages = 32;

and didn't realize, that that 32 is totally irrelevant.

So I'm still right, that for N dirty pages, the writer is allowed to
dirty N/1500*8 more dirty pages, but I agree, that this isn't really
an issue.

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

\
 
 \ /
  Last update: 2007-04-24 14:11    [W:0.097 / U:0.104 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site