On Mon 14-09-20 14:00:33, Matthew Wilcox (Oracle) wrote: > There is a lot of common code in find_get_entries(), > find_get_pages_range() and find_get_pages_range_tag(). Factor out > xas_find_get_entry() which simplifies all three functions. > > Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Looks good. You can add: Reviewed-by: Jan Kara <[email protected]> Honza > --- > mm/filemap.c | 98 +++++++++++++++++++++++----------------------------- > 1 file changed, 43 insertions(+), 55 deletions(-) > > diff --git a/mm/filemap.c b/mm/filemap.c > index 7d8cf1a25628..d8f5ff07eb9c 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -1758,6 +1758,43 @@ struct page *pagecache_get_page(struct address_space > *mapping, pgoff_t index, > } > EXPORT_SYMBOL(pagecache_get_page); > > +static inline struct page *xas_find_get_entry(struct xa_state *xas, > + pgoff_t max, xa_mark_t mark) > +{ > + struct page *page; > + > +retry: > + if (mark == XA_PRESENT) > + page = xas_find(xas, max); > + else > + page = xas_find_marked(xas, max, mark); > + > + if (xas_retry(xas, page)) > + goto retry; > + /* > + * A shadow entry of a recently evicted page, a swap > + * entry from shmem/tmpfs or a DAX entry. Return it > + * without attempting to raise page count. > + */ > + if (!page || xa_is_value(page)) > + return page; > + > + if (!page_cache_get_speculative(page)) > + goto reset; > + > + /* Has the page moved or been split? */ > + if (unlikely(page != xas_reload(xas))) { > + put_page(page); > + goto reset; > + } > + VM_BUG_ON_PAGE(!thp_contains(page, xas->xa_index), page); > + > + return page; > +reset: > + xas_reset(xas); > + goto retry; > +} > + > /** > * find_get_entries - gang pagecache lookup > * @mapping: The address_space to search > @@ -1797,42 +1834,21 @@ unsigned find_get_entries(struct address_space > *mapping, > return 0; > > rcu_read_lock(); > - xas_for_each(&xas, page, ULONG_MAX) { > - if (xas_retry(&xas, page)) > - continue; > - /* > - * A shadow entry of a recently evicted page, a swap > - * entry from shmem/tmpfs or a DAX entry. Return it > - * without attempting to raise page count. > - */ > - if (xa_is_value(page)) > - goto export; > - > - if (!page_cache_get_speculative(page)) > - goto retry; > - > - /* Has the page moved or been split? */ > - if (unlikely(page != xas_reload(&xas))) > - goto put_page; > - > + while ((page = xas_find_get_entry(&xas, ULONG_MAX, XA_PRESENT))) { > /* > * Terminate early on finding a THP, to allow the caller to > * handle it all at once; but continue if this is hugetlbfs. > */ > - if (PageTransHuge(page) && !PageHuge(page)) { > + if (!xa_is_value(page) && PageTransHuge(page) && > + !PageHuge(page)) { > page = find_subpage(page, xas.xa_index); > nr_entries = ret + 1; > } > -export: > + > indices[ret] = xas.xa_index; > entries[ret] = page; > if (++ret == nr_entries) > break; > - continue; > -put_page: > - put_page(page); > -retry: > - xas_reset(&xas); > } > rcu_read_unlock(); > return ret; > @@ -1871,30 +1887,16 @@ unsigned find_get_pages_range(struct address_space > *mapping, pgoff_t *start, > return 0; > > rcu_read_lock(); > - xas_for_each(&xas, page, end) { > - if (xas_retry(&xas, page)) > - continue; > + while ((page = xas_find_get_entry(&xas, end, XA_PRESENT))) { > /* Skip over shadow, swap and DAX entries */ > if (xa_is_value(page)) > continue; > > - if (!page_cache_get_speculative(page)) > - goto retry; > - > - /* Has the page moved or been split? */ > - if (unlikely(page != xas_reload(&xas))) > - goto put_page; > - > pages[ret] = find_subpage(page, xas.xa_index); > if (++ret == nr_pages) { > *start = xas.xa_index + 1; > goto out; > } > - continue; > -put_page: > - put_page(page); > -retry: > - xas_reset(&xas); > } > > /* > @@ -1993,9 +1995,7 @@ unsigned find_get_pages_range_tag(struct address_space > *mapping, pgoff_t *index, > return 0; > > rcu_read_lock(); > - xas_for_each_marked(&xas, page, end, tag) { > - if (xas_retry(&xas, page)) > - continue; > + while ((page = xas_find_get_entry(&xas, end, tag))) { > /* > * Shadow entries should never be tagged, but this iteration > * is lockless so there is a window for page reclaim to evict > @@ -2004,23 +2004,11 @@ unsigned find_get_pages_range_tag(struct > address_space *mapping, pgoff_t *index, > if (xa_is_value(page)) > continue; > > - if (!page_cache_get_speculative(page)) > - goto retry; > - > - /* Has the page moved or been split? */ > - if (unlikely(page != xas_reload(&xas))) > - goto put_page; > - > pages[ret] = page; > if (++ret == nr_pages) { > *index = page->index + thp_nr_pages(page); > goto out; > } > - continue; > -put_page: > - put_page(page); > -retry: > - xas_reset(&xas); > } > > /* > -- > 2.28.0 > -- Jan Kara <[email protected]> SUSE Labs, CR
