lkml.org 
[lkml]   [2007]   [Apr]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Pagecache: find_or_create_page does not call a proper page allocator function
On Tue, 24 Apr 2007 18:45:03 +0100 (BST) Hugh Dickins <hugh@veritas.com> wrote:

> On Tue, 24 Apr 2007, Christoph Lameter wrote:
> > On Tue, 24 Apr 2007, Hugh Dickins wrote:
> >
> > > I've not yet looked at the patch under discussion, but this remark
> > > prompts me... a couple of days ago I got very worried by the various
> > > hard-wired GFP_HIGHUSER allocations in mm/migrate.c and mm/mempolicy.c,
> > > and wondered how those would work out if someone has a blockdev mmap'ed.
> >
> > Hmmm.... These not that critical given that 32 bit NUMA systems are a bit
> > rare.
>
> That's true. And everybody but the owners of those systems wish
> fervently that they didn't exist ;)
>
> > And if a page is in the wrong area then it can be bounced before I/O
> > is performed on it.
>
> I think that much is also true, but not where the problem lies.
> Isn't the problem that filesystems using these block devices
> expect their metadata to be accessible without kmap calls?
>

yup. wherever we dereference buffer_head.b_data we're touching
page_address(buffer_head.b_page) without kmapping.
-
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 19:55    [from the cache]
©2003-2011 Jasper Spaans. Advertise on this site