On Mon 24-01-22 11:34:25, John Hubbard wrote: > On 1/24/22 04:19, Jan Kara wrote: > > > address for each ZERO_PAGE() (unless I'm totally wrong here) and > > > using this check you can distinguish between ZERO_PAGE() and > > > non ZERO_PAGE() on the bio list in bio_release_pages(). > > > > Well, that is another option but it seems a bit ugly and also on some > > architectures (e.g. s390 AFAICS) there can be multiple zero pages (due to > > coloring) so the test for zero page is not completely trivial (probably we > > would have to grow some is_zero_page() checking function implemented > > separately for each arch). > > Good point. And adding an is_zero_page() function would also make some > of these invocations correct across all architectures: > > is_zero_pfn(page_to_pfn(page)) > > ...so it would also be a fix or at least an upgrade. As I'm checking the is_zero_pfn() implementation, it should be working as it should for all architectures. I just forgot we already have a function for this. > I had also wondered why there is no is_zero_page() wrapper function for > the above invocation. Maybe because there are only four call sites and > no one saw it as worthwhile yet. Yeah, perhaps. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
