Re: [PATCH] export swapper_space

[James Bottomley <James.Bottomley@steeleye.com>]

On Sun, 2004-05-23 at 18:04, Andrew Morton wrote:
> I'd be a bit reluctant to do this.  filesystems actually have no need for
> page_mapping() - page->mapping is always correct in that context and
> page_mapping() has additional overhead.  So if poss we should avoid this
> export so as to force filesystems to avoid page_mapping().
> 
> parisc broke because its flush_dcache_page() is inlined, and it uses
> page_mapping().  I'd suggest that parisc and arm uninline that function -
> it's quite large anyway.

You mean our fast path for flush_dcache_page

static inline void flush_dcache_page(struct page *page)
{
        struct address_space *mapping = page_mapping(page);

        if (mapping && !mapping_mapped(mapping)) {
                set_bit(PG_dcache_dirty, &page->flags);
        } else {
                __flush_dcache_page(page);
        }
}

Yes, that's the culprit...I suppose we could uninline it.

James