mm: page cache: store only head pages in i_pages
Transparent Huge Pages are currently stored in i_pages as pointers to consecutive subpages. This patch changes that to storing consecutive pointers to the head page in preparation for storing huge pages more efficiently in i_pages. Large parts of this are "inspired" by Kirill's patch https://lore.kernel.org/lkml/20170126115819.58875-2-kirill.shutemov@linux.intel.com/ [willy@infradead.org: fix swapcache pages] Link: http://lkml.kernel.org/r/20190324155441.GF10344@bombadil.infradead.org [kirill@shutemov.name: hugetlb stores pages in page cache differently] Link: http://lkml.kernel.org/r/20190404134553.vuvhgmghlkiw2hgl@kshutemo-mobl1 Link: http://lkml.kernel.org/r/20190307153051.18815-1-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Acked-by: Jan Kara <jack@suse.cz> Reviewed-by: Kirill Shutemov <kirill@shutemov.name> Reviewed-and-tested-by: Song Liu <songliubraving@fb.com> Tested-by: William Kucharski <william.kucharski@oracle.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Tested-by: Qian Cai <cai@lca.pw> Cc: Hugh Dickins <hughd@google.com> Cc: Song Liu <liu.song.a23@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
cefdca0a86
commit
5fd4ca2d84
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@ -333,6 +333,19 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
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mapping_gfp_mask(mapping));
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}
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static inline struct page *find_subpage(struct page *page, pgoff_t offset)
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{
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unsigned long mask;
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if (PageHuge(page))
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return page;
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VM_BUG_ON_PAGE(PageTail(page), page);
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mask = (1UL << compound_order(page)) - 1;
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return page + (offset & mask);
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}
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struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
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struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset);
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unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
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143
mm/filemap.c
143
mm/filemap.c
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@ -279,11 +279,11 @@ EXPORT_SYMBOL(delete_from_page_cache);
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* @pvec: pagevec with pages to delete
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*
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* The function walks over mapping->i_pages and removes pages passed in @pvec
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* from the mapping. The function expects @pvec to be sorted by page index.
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* from the mapping. The function expects @pvec to be sorted by page index
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* and is optimised for it to be dense.
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* It tolerates holes in @pvec (mapping entries at those indices are not
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* modified). The function expects only THP head pages to be present in the
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* @pvec and takes care to delete all corresponding tail pages from the
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* mapping as well.
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* @pvec.
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*
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* The function expects the i_pages lock to be held.
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*/
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@ -292,40 +292,44 @@ static void page_cache_delete_batch(struct address_space *mapping,
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{
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XA_STATE(xas, &mapping->i_pages, pvec->pages[0]->index);
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int total_pages = 0;
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int i = 0, tail_pages = 0;
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int i = 0;
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struct page *page;
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mapping_set_update(&xas, mapping);
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xas_for_each(&xas, page, ULONG_MAX) {
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if (i >= pagevec_count(pvec) && !tail_pages)
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if (i >= pagevec_count(pvec))
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break;
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/* A swap/dax/shadow entry got inserted? Skip it. */
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if (xa_is_value(page))
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continue;
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if (!tail_pages) {
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/*
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* Some page got inserted in our range? Skip it. We
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* have our pages locked so they are protected from
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* being removed.
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* A page got inserted in our range? Skip it. We have our
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* pages locked so they are protected from being removed.
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* If we see a page whose index is higher than ours, it
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* means our page has been removed, which shouldn't be
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* possible because we're holding the PageLock.
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*/
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if (page != pvec->pages[i]) {
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VM_BUG_ON_PAGE(page->index >
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pvec->pages[i]->index, page);
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VM_BUG_ON_PAGE(page->index > pvec->pages[i]->index,
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page);
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continue;
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}
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WARN_ON_ONCE(!PageLocked(page));
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if (PageTransHuge(page) && !PageHuge(page))
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tail_pages = HPAGE_PMD_NR - 1;
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if (page->index == xas.xa_index)
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page->mapping = NULL;
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/* Leave page->index set: truncation lookup relies on it */
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/*
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* Leave page->index set: truncation lookup relies
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* upon it
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* Move to the next page in the vector if this is a regular
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* page or the index is of the last sub-page of this compound
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* page.
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*/
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if (page->index + (1UL << compound_order(page)) - 1 ==
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xas.xa_index)
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i++;
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} else {
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VM_BUG_ON_PAGE(page->index + HPAGE_PMD_NR - tail_pages
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!= pvec->pages[i]->index, page);
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tail_pages--;
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}
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xas_store(&xas, NULL);
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total_pages++;
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}
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@ -1491,7 +1495,7 @@ EXPORT_SYMBOL(page_cache_prev_miss);
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struct page *find_get_entry(struct address_space *mapping, pgoff_t offset)
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{
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XA_STATE(xas, &mapping->i_pages, offset);
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struct page *head, *page;
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struct page *page;
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rcu_read_lock();
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repeat:
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@ -1506,25 +1510,19 @@ repeat:
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if (!page || xa_is_value(page))
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goto out;
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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(page))
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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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* Has the page moved or been split?
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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 != xas_reload(&xas))) {
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put_page(head);
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put_page(page);
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goto repeat;
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}
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page = find_subpage(page, offset);
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out:
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rcu_read_unlock();
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@ -1706,7 +1704,6 @@ unsigned find_get_entries(struct address_space *mapping,
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rcu_read_lock();
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xas_for_each(&xas, page, ULONG_MAX) {
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struct page *head;
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if (xas_retry(&xas, page))
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continue;
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/*
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@ -1717,17 +1714,13 @@ unsigned find_get_entries(struct address_space *mapping,
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if (xa_is_value(page))
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goto export;
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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(page))
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goto retry;
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/* The page was split under us? */
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if (compound_head(page) != head)
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goto put_page;
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/* Has the page moved? */
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/* Has the page moved or been split? */
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if (unlikely(page != xas_reload(&xas)))
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goto put_page;
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page = find_subpage(page, xas.xa_index);
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export:
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indices[ret] = xas.xa_index;
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@ -1736,7 +1729,7 @@ export:
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break;
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continue;
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put_page:
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put_page(head);
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put_page(page);
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retry:
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xas_reset(&xas);
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}
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@ -1778,33 +1771,27 @@ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
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rcu_read_lock();
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xas_for_each(&xas, page, end) {
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struct page *head;
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if (xas_retry(&xas, page))
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continue;
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/* Skip over shadow, swap and DAX entries */
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if (xa_is_value(page))
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continue;
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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(page))
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goto retry;
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/* The page was split under us? */
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if (compound_head(page) != head)
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goto put_page;
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/* Has the page moved? */
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/* Has the page moved or been split? */
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if (unlikely(page != xas_reload(&xas)))
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goto put_page;
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pages[ret] = page;
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pages[ret] = find_subpage(page, xas.xa_index);
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if (++ret == nr_pages) {
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*start = xas.xa_index + 1;
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goto out;
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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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put_page(page);
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retry:
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xas_reset(&xas);
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}
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@ -1849,7 +1836,6 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
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rcu_read_lock();
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for (page = xas_load(&xas); page; page = xas_next(&xas)) {
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struct page *head;
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if (xas_retry(&xas, page))
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continue;
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/*
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@ -1859,24 +1845,19 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index,
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if (xa_is_value(page))
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break;
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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(page))
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goto retry;
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/* The page was split under us? */
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if (compound_head(page) != head)
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goto put_page;
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/* Has the page moved? */
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/* Has the page moved or been split? */
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if (unlikely(page != xas_reload(&xas)))
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goto put_page;
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pages[ret] = page;
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pages[ret] = find_subpage(page, xas.xa_index);
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if (++ret == nr_pages)
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break;
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continue;
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put_page:
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put_page(head);
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put_page(page);
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retry:
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xas_reset(&xas);
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}
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@ -1912,7 +1893,6 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
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rcu_read_lock();
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xas_for_each_marked(&xas, page, end, tag) {
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struct page *head;
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if (xas_retry(&xas, page))
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continue;
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/*
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@ -1923,26 +1903,21 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
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if (xa_is_value(page))
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continue;
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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(page))
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goto retry;
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/* The page was split under us? */
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if (compound_head(page) != head)
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goto put_page;
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/* Has the page moved? */
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/* Has the page moved or been split? */
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if (unlikely(page != xas_reload(&xas)))
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goto put_page;
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pages[ret] = page;
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pages[ret] = find_subpage(page, xas.xa_index);
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if (++ret == nr_pages) {
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*index = xas.xa_index + 1;
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goto out;
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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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put_page(page);
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retry:
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xas_reset(&xas);
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}
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@ -1991,7 +1966,6 @@ unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
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rcu_read_lock();
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xas_for_each_marked(&xas, page, ULONG_MAX, tag) {
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struct page *head;
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if (xas_retry(&xas, page))
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continue;
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/*
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@ -2002,17 +1976,13 @@ unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
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if (xa_is_value(page))
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goto export;
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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(page))
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goto retry;
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/* The page was split under us? */
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if (compound_head(page) != head)
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goto put_page;
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/* Has the page moved? */
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/* Has the page moved or been split? */
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if (unlikely(page != xas_reload(&xas)))
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goto put_page;
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page = find_subpage(page, xas.xa_index);
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export:
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indices[ret] = xas.xa_index;
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@ -2021,7 +1991,7 @@ export:
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break;
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continue;
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put_page:
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put_page(head);
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put_page(page);
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retry:
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xas_reset(&xas);
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}
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@ -2691,7 +2661,7 @@ void filemap_map_pages(struct vm_fault *vmf,
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pgoff_t last_pgoff = start_pgoff;
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unsigned long max_idx;
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XA_STATE(xas, &mapping->i_pages, start_pgoff);
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struct page *head, *page;
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struct page *page;
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rcu_read_lock();
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xas_for_each(&xas, page, end_pgoff) {
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@ -2700,24 +2670,19 @@ void filemap_map_pages(struct vm_fault *vmf,
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if (xa_is_value(page))
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goto next;
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head = compound_head(page);
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/*
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* Check for a locked page first, as a speculative
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* reference may adversely influence page migration.
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*/
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if (PageLocked(head))
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if (PageLocked(page))
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goto next;
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if (!page_cache_get_speculative(head))
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if (!page_cache_get_speculative(page))
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goto next;
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/* The page was split under us? */
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if (compound_head(page) != head)
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goto skip;
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/* Has the page moved? */
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/* Has the page moved or been split? */
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if (unlikely(page != xas_reload(&xas)))
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goto skip;
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page = find_subpage(page, xas.xa_index);
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if (!PageUptodate(page) ||
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PageReadahead(page) ||
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@ -2496,6 +2496,9 @@ static void __split_huge_page(struct page *page, struct list_head *list,
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if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head))
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shmem_uncharge(head->mapping->host, 1);
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put_page(head + i);
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} else if (!PageAnon(page)) {
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__xa_store(&head->mapping->i_pages, head[i].index,
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head + i, 0);
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}
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}
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@ -1374,7 +1374,7 @@ static void collapse_shmem(struct mm_struct *mm,
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result = SCAN_FAIL;
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goto xa_locked;
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}
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xas_store(&xas, new_page + (index % HPAGE_PMD_NR));
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xas_store(&xas, new_page);
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nr_none++;
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continue;
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}
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@ -1450,7 +1450,7 @@ static void collapse_shmem(struct mm_struct *mm,
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list_add_tail(&page->lru, &pagelist);
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/* Finally, replace with the new page. */
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xas_store(&xas, new_page + (index % HPAGE_PMD_NR));
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xas_store(&xas, new_page);
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continue;
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out_unlock:
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unlock_page(page);
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|
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@ -39,6 +39,7 @@ static void memfd_tag_pins(struct xa_state *xas)
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xas_for_each(xas, page, ULONG_MAX) {
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if (xa_is_value(page))
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continue;
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page = find_subpage(page, xas->xa_index);
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if (page_count(page) - page_mapcount(page) > 1)
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xas_set_mark(xas, MEMFD_TAG_PINNED);
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@ -88,6 +89,7 @@ static int memfd_wait_for_pins(struct address_space *mapping)
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bool clear = true;
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if (xa_is_value(page))
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continue;
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page = find_subpage(page, xas.xa_index);
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if (page_count(page) - page_mapcount(page) != 1) {
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/*
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* On the last scan, we clean up all those tags
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|
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@ -463,7 +463,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
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for (i = 1; i < HPAGE_PMD_NR; i++) {
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xas_next(&xas);
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xas_store(&xas, newpage + i);
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xas_store(&xas, newpage);
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}
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}
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|
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@ -614,7 +614,7 @@ static int shmem_add_to_page_cache(struct page *page,
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if (xas_error(&xas))
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goto unlock;
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next:
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xas_store(&xas, page + i);
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xas_store(&xas, page);
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if (++i < nr) {
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xas_next(&xas);
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goto next;
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|
|
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@ -132,7 +132,7 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp)
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for (i = 0; i < nr; i++) {
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VM_BUG_ON_PAGE(xas.xa_index != idx + i, page);
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set_page_private(page + i, entry.val + i);
|
||||
xas_store(&xas, page + i);
|
||||
xas_store(&xas, page);
|
||||
xas_next(&xas);
|
||||
}
|
||||
address_space->nrpages += nr;
|
||||
|
@ -167,7 +167,7 @@ void __delete_from_swap_cache(struct page *page, swp_entry_t entry)
|
|||
|
||||
for (i = 0; i < nr; i++) {
|
||||
void *entry = xas_store(&xas, NULL);
|
||||
VM_BUG_ON_PAGE(entry != page + i, entry);
|
||||
VM_BUG_ON_PAGE(entry != page, entry);
|
||||
set_page_private(page + i, 0);
|
||||
xas_next(&xas);
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue