From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
linux-kernel@vger.kernel.org
Subject: [RFC PATCH 09/11] mm/filemap: Convert mapping_get_entry and pagecache_get_page to folio
Date: Tue, 8 Dec 2020 19:46:51 +0000 [thread overview]
Message-ID: <20201208194653.19180-10-willy@infradead.org> (raw)
In-Reply-To: <20201208194653.19180-1-willy@infradead.org>
Convert mapping_get_entry() to return a folio and convert
pagecache_get_page() to use the folio where possible. The seemingly
dangerous cast of a page pointer to a folio pointer is safe because
__page_cache_alloc() allocates an order-0 page, which is a folio by
definition.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
mm/filemap.c | 45 ++++++++++++++++++++++++---------------------
1 file changed, 24 insertions(+), 21 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index f1b65f777539..56ff6aa24265 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1673,33 +1673,33 @@ EXPORT_SYMBOL(page_cache_prev_miss);
* @index: The page cache index.
*
* Looks up the page cache slot at @mapping & @offset. If there is a
- * page cache page, the head page is returned with an increased refcount.
+ * page cache page, the folio is returned with an increased refcount.
*
* If the slot holds a shadow entry of a previously evicted page, or a
* swap entry from shmem/tmpfs, it is returned.
*
- * Return: The head page or shadow entry, %NULL if nothing is found.
+ * Return: The folio or shadow entry, %NULL if nothing is found.
*/
-static struct page *mapping_get_entry(struct address_space *mapping,
+static struct folio *mapping_get_entry(struct address_space *mapping,
pgoff_t index)
{
XA_STATE(xas, &mapping->i_pages, index);
- struct page *page;
+ struct folio *folio;
rcu_read_lock();
repeat:
xas_reset(&xas);
- page = xas_load(&xas);
- if (xas_retry(&xas, page))
+ folio = xas_load(&xas);
+ if (xas_retry(&xas, folio))
goto repeat;
/*
* A shadow entry of a recently evicted page, or a swap entry from
* shmem/tmpfs. Return it without attempting to raise page count.
*/
- if (!page || xa_is_value(page))
+ if (!folio || xa_is_value(folio))
goto out;
- if (!page_cache_get_speculative(page))
+ if (!page_cache_get_speculative(&folio->page))
goto repeat;
/*
@@ -1707,14 +1707,14 @@ static struct page *mapping_get_entry(struct address_space *mapping,
* This is part of the lockless pagecache protocol. See
* include/linux/pagemap.h for details.
*/
- if (unlikely(page != xas_reload(&xas))) {
- put_page(page);
+ if (unlikely(folio != xas_reload(&xas))) {
+ put_folio(folio);
goto repeat;
}
out:
rcu_read_unlock();
- return page;
+ return folio;
}
/**
@@ -1754,11 +1754,13 @@ static struct page *mapping_get_entry(struct address_space *mapping,
struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
int fgp_flags, gfp_t gfp_mask)
{
+ struct folio *folio;
struct page *page;
repeat:
- page = mapping_get_entry(mapping, index);
- if (xa_is_value(page)) {
+ folio = mapping_get_entry(mapping, index);
+ page = &folio->page;
+ if (xa_is_value(folio)) {
if (fgp_flags & FGP_ENTRY)
return page;
page = NULL;
@@ -1768,18 +1770,18 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
if (fgp_flags & FGP_LOCK) {
if (fgp_flags & FGP_NOWAIT) {
- if (!trylock_page(page)) {
- put_page(page);
+ if (!trylock_folio(folio)) {
+ put_folio(folio);
return NULL;
}
} else {
- lock_page(page);
+ lock_folio(folio);
}
/* Has the page been truncated? */
if (unlikely(page->mapping != mapping)) {
- unlock_page(page);
- put_page(page);
+ unlock_folio(folio);
+ put_folio(folio);
goto repeat;
}
VM_BUG_ON_PAGE(!thp_contains(page, index), page);
@@ -1806,17 +1808,18 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
page = __page_cache_alloc(gfp_mask);
if (!page)
return NULL;
+ folio = (struct folio *)page;
if (WARN_ON_ONCE(!(fgp_flags & (FGP_LOCK | FGP_FOR_MMAP))))
fgp_flags |= FGP_LOCK;
/* Init accessed so avoid atomic mark_page_accessed later */
if (fgp_flags & FGP_ACCESSED)
- __SetPageReferenced(page);
+ __SetFolioReferenced(folio);
err = add_to_page_cache_lru(page, mapping, index, gfp_mask);
if (unlikely(err)) {
- put_page(page);
+ put_folio(folio);
page = NULL;
if (err == -EEXIST)
goto repeat;
@@ -1827,7 +1830,7 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
* an unlocked page.
*/
if (page && (fgp_flags & FGP_FOR_MMAP))
- unlock_page(page);
+ unlock_folio(folio);
}
return page;
--
2.29.2
next prev parent reply other threads:[~2020-12-08 20:11 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-08 19:46 [RFC PATCH 00/11] Page folios Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 01/11] mm: Introduce struct folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 02/11] mm: Add put_folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 03/11] mm: Add get_folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 04/11] mm: Create FolioFlags Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 05/11] mm: Add unlock_folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 06/11] mm: Add lock_folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 07/11] mm: Add lock_folio_killable Matthew Wilcox (Oracle)
2020-12-08 19:46 ` [RFC PATCH 08/11] mm/filemap: Convert end_page_writeback to use a folio Matthew Wilcox (Oracle)
2020-12-08 19:46 ` Matthew Wilcox (Oracle) [this message]
2020-12-08 19:46 ` [RFC PATCH 10/11] mm/filemap: Add folio_add_to_page_cache Matthew Wilcox (Oracle)
2020-12-11 8:32 ` Nikolay Borisov
2020-12-08 19:46 ` [RFC PATCH 11/11] mm/swap: Convert rotate_reclaimable_page to folio Matthew Wilcox (Oracle)
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