filemap: prepare find and delete operations for huge pages
For now, we would have HPAGE_PMD_NR entries in radix tree for every huge page. That's suboptimal and it will be changed to use Matthew's multi-order entries later. 'add' operation is not changed, because we don't need it to implement hugetmpfs: shmem uses its own implementation. Link: http://lkml.kernel.org/r/1466021202-61880-25-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov
Linus Torvalds
Родитель
c78c66d1dd
Коммит
83929372f6
178
mm/filemap.c
178
mm/filemap.c
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@ -114,14 +114,14 @@ static void page_cache_tree_delete(struct address_space *mapping,
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struct page *page, void *shadow)
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{
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struct radix_tree_node *node;
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int i, nr = PageHuge(page) ? 1 : hpage_nr_pages(page);
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VM_BUG_ON(!PageLocked(page));
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node = radix_tree_replace_clear_tags(&mapping->page_tree, page->index,
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shadow);
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VM_BUG_ON_PAGE(!PageLocked(page), page);
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VM_BUG_ON_PAGE(PageTail(page), page);
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VM_BUG_ON_PAGE(nr != 1 && shadow, page);
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if (shadow) {
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mapping->nrexceptional++;
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mapping->nrexceptional += nr;
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/*
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* Make sure the nrexceptional update is committed before
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* the nrpages update so that final truncate racing
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@ -130,31 +130,38 @@ static void page_cache_tree_delete(struct address_space *mapping,
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*/
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smp_wmb();
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}
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mapping->nrpages--;
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mapping->nrpages -= nr;
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if (!node)
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return;
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workingset_node_pages_dec(node);
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if (shadow)
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workingset_node_shadows_inc(node);
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else
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if (__radix_tree_delete_node(&mapping->page_tree, node))
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for (i = 0; i < nr; i++) {
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node = radix_tree_replace_clear_tags(&mapping->page_tree,
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page->index + i, shadow);
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if (!node) {
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VM_BUG_ON_PAGE(nr != 1, page);
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return;
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}
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/*
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* Track node that only contains shadow entries. DAX mappings contain
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* no shadow entries and may contain other exceptional entries so skip
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* those.
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*
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* Avoid acquiring the list_lru lock if already tracked. The
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* list_empty() test is safe as node->private_list is
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* protected by mapping->tree_lock.
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*/
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if (!dax_mapping(mapping) && !workingset_node_pages(node) &&
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list_empty(&node->private_list)) {
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node->private_data = mapping;
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list_lru_add(&workingset_shadow_nodes, &node->private_list);
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workingset_node_pages_dec(node);
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if (shadow)
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workingset_node_shadows_inc(node);
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else
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if (__radix_tree_delete_node(&mapping->page_tree, node))
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continue;
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/*
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* Track node that only contains shadow entries. DAX mappings
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* contain no shadow entries and may contain other exceptional
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* entries so skip those.
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*
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* Avoid acquiring the list_lru lock if already tracked.
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* The list_empty() test is safe as node->private_list is
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* protected by mapping->tree_lock.
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*/
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if (!dax_mapping(mapping) && !workingset_node_pages(node) &&
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list_empty(&node->private_list)) {
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node->private_data = mapping;
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list_lru_add(&workingset_shadow_nodes,
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&node->private_list);
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}
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}
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}
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@ -166,6 +173,7 @@ static void page_cache_tree_delete(struct address_space *mapping,
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void __delete_from_page_cache(struct page *page, void *shadow)
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{
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struct address_space *mapping = page->mapping;
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int nr = hpage_nr_pages(page);
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trace_mm_filemap_delete_from_page_cache(page);
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/*
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@ -178,6 +186,7 @@ void __delete_from_page_cache(struct page *page, void *shadow)
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else
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cleancache_invalidate_page(mapping, page);
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VM_BUG_ON_PAGE(PageTail(page), page);
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VM_BUG_ON_PAGE(page_mapped(page), page);
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if (!IS_ENABLED(CONFIG_DEBUG_VM) && unlikely(page_mapped(page))) {
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int mapcount;
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@ -209,9 +218,9 @@ void __delete_from_page_cache(struct page *page, void *shadow)
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/* hugetlb pages do not participate in page cache accounting. */
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if (!PageHuge(page))
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__dec_zone_page_state(page, NR_FILE_PAGES);
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__mod_zone_page_state(page_zone(page), NR_FILE_PAGES, -nr);
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if (PageSwapBacked(page))
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__dec_zone_page_state(page, NR_SHMEM);
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__mod_zone_page_state(page_zone(page), NR_SHMEM, -nr);
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/*
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* At this point page must be either written or cleaned by truncate.
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@ -235,9 +244,8 @@ void __delete_from_page_cache(struct page *page, void *shadow)
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*/
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void delete_from_page_cache(struct page *page)
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{
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struct address_space *mapping = page->mapping;
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struct address_space *mapping = page_mapping(page);
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unsigned long flags;
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void (*freepage)(struct page *);
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BUG_ON(!PageLocked(page));
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@ -250,7 +258,13 @@ void delete_from_page_cache(struct page *page)
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if (freepage)
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freepage(page);
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put_page(page);
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if (PageTransHuge(page) && !PageHuge(page)) {
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page_ref_sub(page, HPAGE_PMD_NR);
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VM_BUG_ON_PAGE(page_count(page) <= 0, page);
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} else {
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put_page(page);
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}
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}
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EXPORT_SYMBOL(delete_from_page_cache);
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@ -1053,7 +1067,7 @@ EXPORT_SYMBOL(page_cache_prev_hole);
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struct page *find_get_entry(struct address_space *mapping, pgoff_t offset)
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{
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void **pagep;
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struct page *page;
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struct page *head, *page;
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rcu_read_lock();
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repeat:
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@ -1073,16 +1087,24 @@ repeat:
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*/
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goto out;
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}
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if (!page_cache_get_speculative(page))
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head = compound_head(page);
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if (!page_cache_get_speculative(head))
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goto repeat;
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/* The page was split under us? */
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if (compound_head(page) != head) {
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put_page(head);
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goto repeat;
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}
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/*
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* Has the page moved?
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* This is part of the lockless pagecache protocol. See
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* include/linux/pagemap.h for details.
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*/
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if (unlikely(page != *pagep)) {
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put_page(page);
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put_page(head);
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goto repeat;
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}
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}
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@ -1118,12 +1140,12 @@ repeat:
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if (page && !radix_tree_exception(page)) {
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lock_page(page);
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/* Has the page been truncated? */
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if (unlikely(page->mapping != mapping)) {
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if (unlikely(page_mapping(page) != mapping)) {
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unlock_page(page);
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put_page(page);
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goto repeat;
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}
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VM_BUG_ON_PAGE(page->index != offset, page);
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VM_BUG_ON_PAGE(page_to_pgoff(page) != offset, page);
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}
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return page;
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}
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@ -1255,7 +1277,7 @@ unsigned find_get_entries(struct address_space *mapping,
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rcu_read_lock();
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radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
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struct page *page;
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struct page *head, *page;
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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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@ -1272,12 +1294,20 @@ repeat:
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*/
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goto export;
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}
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if (!page_cache_get_speculative(page))
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head = compound_head(page);
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if (!page_cache_get_speculative(head))
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goto repeat;
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/* The page was split under us? */
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if (compound_head(page) != head) {
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put_page(head);
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goto repeat;
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}
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/* Has the page moved? */
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if (unlikely(page != *slot)) {
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put_page(page);
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put_page(head);
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goto repeat;
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}
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export:
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@ -1318,7 +1348,7 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
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rcu_read_lock();
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radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
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struct page *page;
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struct page *head, *page;
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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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@ -1337,12 +1367,19 @@ repeat:
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continue;
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}
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if (!page_cache_get_speculative(page))
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head = compound_head(page);
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if (!page_cache_get_speculative(head))
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goto repeat;
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/* The page was split under us? */
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if (compound_head(page) != head) {
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put_page(head);
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goto repeat;
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}
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/* Has the page moved? */
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if (unlikely(page != *slot)) {
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put_page(page);
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put_page(head);
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goto repeat;
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}
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@ -1379,7 +1416,7 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
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rcu_read_lock();
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radix_tree_for_each_contig(slot, &mapping->page_tree, &iter, index) {
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struct page *page;
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struct page *head, *page;
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repeat:
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page = radix_tree_deref_slot(slot);
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/* The hole, there no reason to continue */
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@ -1399,12 +1436,19 @@ repeat:
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break;
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}
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if (!page_cache_get_speculative(page))
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head = compound_head(page);
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if (!page_cache_get_speculative(head))
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goto repeat;
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/* The page was split under us? */
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if (compound_head(page) != head) {
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put_page(head);
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goto repeat;
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}
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/* Has the page moved? */
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if (unlikely(page != *slot)) {
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put_page(page);
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put_page(head);
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goto repeat;
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}
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@ -1413,7 +1457,7 @@ repeat:
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* otherwise we can get both false positives and false
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* negatives, which is just confusing to the caller.
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*/
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if (page->mapping == NULL || page->index != iter.index) {
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if (page->mapping == NULL || page_to_pgoff(page) != iter.index) {
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put_page(page);
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break;
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}
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@ -1451,7 +1495,7 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
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rcu_read_lock();
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radix_tree_for_each_tagged(slot, &mapping->page_tree,
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&iter, *index, tag) {
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struct page *page;
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struct page *head, *page;
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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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@ -1476,12 +1520,19 @@ repeat:
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continue;
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}
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if (!page_cache_get_speculative(page))
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head = compound_head(page);
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if (!page_cache_get_speculative(head))
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goto repeat;
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/* The page was split under us? */
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if (compound_head(page) != head) {
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put_page(head);
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goto repeat;
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}
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/* Has the page moved? */
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if (unlikely(page != *slot)) {
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put_page(page);
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put_page(head);
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goto repeat;
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}
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@ -1525,7 +1576,7 @@ unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
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rcu_read_lock();
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radix_tree_for_each_tagged(slot, &mapping->page_tree,
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&iter, start, tag) {
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struct page *page;
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struct page *head, *page;
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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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@ -1543,12 +1594,20 @@ repeat:
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*/
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goto export;
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}
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if (!page_cache_get_speculative(page))
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head = compound_head(page);
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if (!page_cache_get_speculative(head))
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goto repeat;
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/* The page was split under us? */
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if (compound_head(page) != head) {
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put_page(head);
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goto repeat;
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}
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/* Has the page moved? */
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if (unlikely(page != *slot)) {
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put_page(page);
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put_page(head);
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goto repeat;
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}
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export:
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@ -2137,7 +2196,7 @@ void filemap_map_pages(struct fault_env *fe,
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struct address_space *mapping = file->f_mapping;
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pgoff_t last_pgoff = start_pgoff;
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loff_t size;
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struct page *page;
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struct page *head, *page;
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rcu_read_lock();
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radix_tree_for_each_slot(slot, &mapping->page_tree, &iter,
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@ -2156,12 +2215,19 @@ repeat:
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goto next;
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}
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if (!page_cache_get_speculative(page))
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head = compound_head(page);
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if (!page_cache_get_speculative(head))
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goto repeat;
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/* The page was split under us? */
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if (compound_head(page) != head) {
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put_page(head);
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goto repeat;
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}
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/* Has the page moved? */
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if (unlikely(page != *slot)) {
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put_page(page);
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put_page(head);
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goto repeat;
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}
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