lkml.org 
[lkml]   [2007]   [Jul]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: RFC: CONFIG_PAGE_SHIFT (aka software PAGE_SIZE)
On Thu, Jul 12, 2007 at 01:14:36PM +0200, Andrea Arcangeli wrote:
> On Thu, Jul 12, 2007 at 10:12:56AM +1000, David Chinner wrote:
> > I need really large filesystems that contain both small and large files to
> > work more efficiently on small boxes where we can't throw endless amounts of
> > RAM and CPUs at the problem. Hence things like 64k page size are just not an
> > option because of the wastage that it entails.
>
> I didn't know you were allocating 4k pages for the small files and 64k
> for the large ones in the same fs. That sounds quite a bit
> overkill.

We already have rudimentary multi-block size support via the
per-inode extent size hint, but we still cache based on the
filesystem block size ('coz we can't increase it).

All I want is to be able to change the index granularity in the page
cache with minimal impact and everything in XFS falls almost
straight out in a pretty optimal manner.

> I still think you should run those systems with PAGE_SIZE 64k even if
> it'll waste you more memory on the small files.

That's crap. Just because a machine has lots of memory does not
make it OK to waste lots of memory.

Cheers,

Dave.
--
Dave Chinner
Principal Engineer
SGI Australian Software Group
-
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: 2007-07-12 16:47    [W:0.051 / U:0.756 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site