On Mon, Jun 24, 2019 at 02:01:05PM +0000, Song Liu wrote:
> >> @@ -1392,6 +1403,23 @@ static void collapse_file(struct mm_struct *mm,
> >> result = SCAN_FAIL;
> >> goto xa_unlocked;
> >> }
> >> + } else if (!page || xa_is_value(page)) {
> >> + xas_unlock_irq(&xas);
> >> + page_cache_sync_readahead(mapping, &file->f_ra, file,
> >> + index, PAGE_SIZE);
> >> + lru_add_drain();
> >
> > Why?
>
> isolate_lru_page() is likely to fail if we don't drain the pagevecs.
Please add a comment.
> >> + page = find_lock_page(mapping, index);
> >> + if (unlikely(page == NULL)) {
> >> + result = SCAN_FAIL;
> >> + goto xa_unlocked;
> >> + }
> >> + } else if (!PageUptodate(page)) {
> >
> > Maybe we should try wait_on_page_locked() here before give up?
>
> Are you referring to the "if (!PageUptodate(page))" case?
Yes.
--
Kirill A. Shutemov
