Re: Bug in page_cache_tree_delete?

[Jan Kara <jack@suse.cz>]

On Tue 08-11-16 16:03:07, Kirill A. Shutemov wrote:
> On Tue, Nov 08, 2016 at 11:35:41AM +0100, Jan Kara wrote:
> > Hi Kirill,
> > 
> > I've noticed that your commit 83929372f629 (filemap: prepare find and
> > delete operations for huge pages) added to page_cache_tree_delete():
> > 
> > 	int i, nr = PageHuge(page) ? 1 : hpage_nr_pages(page);
> > 
> > Isn't the logic computing 'nr' inverted? I'd expect that if page is
> > !PageHuge, we want to delete just one page... OTOH I'm surprised this would
> > not blow up anywhere if it was really wrong so maybe I just miss something.
> 
> No, that's not bug.
> 
> PageHuge() detects hugetlb pages (we probably should rename the helper)
> which represented by one entry on radix-tree per huge page.

Ah, right. Thanks for explanation! Maybe that line would deserve a comment?

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>