Re: [PATCH v14 062/138] mm/migrate: Add folio_migrate_copy()

Dmitry Osipenko
2021-07-22T13:46:05Z

22.07.2021 15:29, Matthew Wilcox пишет:
> On Thu, Jul 22, 2021 at 02:52:28PM +0300, Dmitry Osipenko wrote:
...
> The obvious solution is just to change folio_copy():
>
> {
> - unsigned i, nr = folio_nr_pages(src);
> + unsigned i = 0;
> + unsigned nr = folio_nr_pages(src);
>
> - for (i = 0; i < nr; i++) {
> - cond_resched();
> + for (;;) {
> copy_highpage(folio_page(dst, i), folio_page(src, i));
> + if (i++ == nr)

This works with the ++i precedence change. Thanks!

> + break;
> + cond_resched();
> }
> }
>
> now it only calls cond_resched() for multi-page folios.

...

Thank you for the explanation and for the fix!

The fs/ and mm/ are mostly outside of my scope, hope you'll figure out
the buffer-head case soon.