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page cache; Convert find_get_pages_range_tag to XArray
The 'end' parameter of the xas_for_each iterator avoids a useless iteration at the end of the range. Signed-off-by: Matthew Wilcox <willy@infradead.org>
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3ece58a270
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2 changed files with 28 additions and 44 deletions
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@ -363,10 +363,10 @@ static inline unsigned find_get_pages(struct address_space *mapping,
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unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
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unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
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unsigned int nr_pages, struct page **pages);
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unsigned int nr_pages, struct page **pages);
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unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
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unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
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pgoff_t end, int tag, unsigned int nr_pages,
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pgoff_t end, xa_mark_t tag, unsigned int nr_pages,
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struct page **pages);
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struct page **pages);
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static inline unsigned find_get_pages_tag(struct address_space *mapping,
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static inline unsigned find_get_pages_tag(struct address_space *mapping,
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pgoff_t *index, int tag, unsigned int nr_pages,
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pgoff_t *index, xa_mark_t tag, unsigned int nr_pages,
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struct page **pages)
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struct page **pages)
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{
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{
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return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag,
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return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag,
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64
mm/filemap.c
64
mm/filemap.c
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@ -1789,74 +1789,58 @@ EXPORT_SYMBOL(find_get_pages_contig);
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* @tag. We update @index to index the next page for the traversal.
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* @tag. We update @index to index the next page for the traversal.
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*/
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*/
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unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
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unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
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pgoff_t end, int tag, unsigned int nr_pages,
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pgoff_t end, xa_mark_t tag, unsigned int nr_pages,
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struct page **pages)
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struct page **pages)
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{
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{
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struct radix_tree_iter iter;
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XA_STATE(xas, &mapping->i_pages, *index);
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void **slot;
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struct page *page;
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unsigned ret = 0;
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unsigned ret = 0;
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if (unlikely(!nr_pages))
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if (unlikely(!nr_pages))
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return 0;
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return 0;
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rcu_read_lock();
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rcu_read_lock();
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radix_tree_for_each_tagged(slot, &mapping->i_pages, &iter, *index, tag) {
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xas_for_each_marked(&xas, page, end, tag) {
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struct page *head, *page;
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struct page *head;
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if (xas_retry(&xas, page))
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if (iter.index > end)
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break;
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repeat:
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page = radix_tree_deref_slot(slot);
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if (unlikely(!page))
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continue;
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continue;
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if (radix_tree_exception(page)) {
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if (radix_tree_deref_retry(page)) {
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slot = radix_tree_iter_retry(&iter);
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continue;
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}
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/*
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/*
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* A shadow entry of a recently evicted page.
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* Shadow entries should never be tagged, but this iteration
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*
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* is lockless so there is a window for page reclaim to evict
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* Those entries should never be tagged, but
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* a page we saw tagged. Skip over it.
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* this tree walk is lockless and the tags are
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* looked up in bulk, one radix tree node at a
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* time, so there is a sizable window for page
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* reclaim to evict a page we saw tagged.
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*
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* Skip over it.
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*/
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*/
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if (xa_is_value(page))
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continue;
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continue;
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}
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head = compound_head(page);
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head = compound_head(page);
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if (!page_cache_get_speculative(head))
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if (!page_cache_get_speculative(head))
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goto repeat;
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goto retry;
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/* The page was split under us? */
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/* The page was split under us? */
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if (compound_head(page) != head) {
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if (compound_head(page) != head)
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put_page(head);
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goto put_page;
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goto repeat;
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}
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/* Has the page moved? */
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/* Has the page moved? */
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if (unlikely(page != *slot)) {
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if (unlikely(page != xas_reload(&xas)))
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put_page(head);
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goto put_page;
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goto repeat;
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}
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pages[ret] = page;
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pages[ret] = page;
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if (++ret == nr_pages) {
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if (++ret == nr_pages) {
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*index = pages[ret - 1]->index + 1;
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*index = page->index + 1;
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goto out;
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goto out;
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}
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}
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continue;
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put_page:
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put_page(head);
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retry:
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xas_reset(&xas);
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}
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}
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/*
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/*
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* We come here when we got at @end. We take care to not overflow the
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* We come here when we got to @end. We take care to not overflow the
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* index @index as it confuses some of the callers. This breaks the
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* index @index as it confuses some of the callers. This breaks the
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* iteration when there is page at index -1 but that is already broken
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* iteration when there is a page at index -1 but that is already
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* anyway.
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* broken anyway.
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*/
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*/
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if (end == (pgoff_t)-1)
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if (end == (pgoff_t)-1)
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*index = (pgoff_t)-1;
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*index = (pgoff_t)-1;
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