All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: akpm@linux-foundation.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2 44/46] mm/filemap: Convert mapping_get_entry to return a folio
Date: Tue, 22 Jun 2021 13:15:49 +0100	[thread overview]
Message-ID: <20210622121551.3398730-45-willy@infradead.org> (raw)
In-Reply-To: <20210622121551.3398730-1-willy@infradead.org>

The pagecache only contains folios, so indicate that this is definitely
not a tail page.  Shrinks mapping_get_entry() by 56 bytes, but grows
pagecache_get_page() by 21 bytes as gcc makes slightly different hot/cold
code decisions.  A net reduction of 35 bytes of text.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/filemap.c | 38 +++++++++++++++++---------------------
 1 file changed, 17 insertions(+), 21 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index a174f8ce87ea..7d0b51f30223 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1754,49 +1754,43 @@ EXPORT_SYMBOL(page_cache_prev_miss);
  * @mapping: the address_space to search
  * @index: The page cache index.
  *
- * Looks up the page cache slot at @mapping & @index.  If there is a
- * page cache page, the head page is returned with an increased refcount.
+ * Looks up the page cache entry at @mapping & @index.  If it is a folio,
+ * it is returned with an increased refcount.  If it is a shadow entry
+ * of a previously evicted folio, or a swap entry from shmem/tmpfs,
+ * it is returned without further action.
  *
- * 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, swap 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 (!folio_try_get_rcu(folio))
 		goto repeat;
 
-	/*
-	 * Has the page moved or been split?
-	 * 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))) {
+		folio_put(folio);
 		goto repeat;
 	}
 out:
 	rcu_read_unlock();
 
-	return page;
+	return folio;
 }
 
 /**
@@ -1836,10 +1830,12 @@ 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);
+	folio = mapping_get_entry(mapping, index);
+	page = &folio->page;
 	if (xa_is_value(page)) {
 		if (fgp_flags & FGP_ENTRY)
 			return page;
-- 
2.30.2


  parent reply	other threads:[~2021-06-22 12:55 UTC|newest]

Thread overview: 128+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-22 12:15 [PATCH v2 00/46] Folio-enabling the page cache Matthew Wilcox (Oracle)
2021-06-22 12:15 ` [PATCH v2 01/46] mm: Add folio_to_pfn() Matthew Wilcox (Oracle)
2021-06-23  7:49   ` Christoph Hellwig
2021-06-24 15:12     ` Matthew Wilcox
2021-06-28  6:18       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 02/46] mm: Add folio_rmapping() Matthew Wilcox (Oracle)
2021-06-23  7:56   ` Christoph Hellwig
2021-06-24 15:51     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 03/46] mm: Add kmap_local_folio() Matthew Wilcox (Oracle)
2021-06-23  7:58   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 04/46] mm: Add flush_dcache_folio() Matthew Wilcox (Oracle)
2021-06-22 12:15 ` [PATCH v2 05/46] mm: Add arch_make_folio_accessible() Matthew Wilcox (Oracle)
2021-06-23  8:00   ` Christoph Hellwig
2021-06-24 15:57     ` Matthew Wilcox
2021-06-28  6:21       ` Christoph Hellwig
2021-06-28 14:07         ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 06/46] mm: Add folio_young() and folio_idle() Matthew Wilcox (Oracle)
2021-06-22 12:15 ` [PATCH v2 07/46] mm/workingset: Convert workingset_activation to take a folio Matthew Wilcox (Oracle)
2021-06-23  8:02   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 08/46] mm/swap: Add folio_activate() Matthew Wilcox (Oracle)
2021-06-23  8:04   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 09/46] mm/swap: Add folio_mark_accessed() Matthew Wilcox (Oracle)
2021-06-23  8:07   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 10/46] mm/rmap: Add folio_mkclean() Matthew Wilcox (Oracle)
2021-06-23  8:08   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 11/46] mm/memcg: Remove 'page' parameter to mem_cgroup_charge_statistics() Matthew Wilcox (Oracle)
2021-06-23  8:09   ` Christoph Hellwig
2021-06-25  7:58   ` Michal Hocko
2021-06-22 12:15 ` [PATCH v2 12/46] mm/memcg: Use the node id in mem_cgroup_update_tree() Matthew Wilcox (Oracle)
2021-06-23  8:12   ` Christoph Hellwig
2021-06-24 16:19     ` Matthew Wilcox
2021-06-25  8:05       ` Michal Hocko
2021-06-22 12:15 ` [PATCH v2 13/46] mm/memcg: Convert commit_charge() to take a folio Matthew Wilcox (Oracle)
2021-06-23  8:13   ` Christoph Hellwig
2021-06-25  8:11   ` Michal Hocko
2021-06-22 12:15 ` [PATCH v2 14/46] mm/memcg: Add folio_charge_cgroup() Matthew Wilcox (Oracle)
2021-06-23  8:15   ` Christoph Hellwig
2021-06-24 16:42     ` Matthew Wilcox
2021-06-25  8:22       ` Michal Hocko
2021-06-25 11:34         ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 15/46] mm/memcg: Add folio_uncharge_cgroup() Matthew Wilcox (Oracle)
2021-06-23  8:16   ` Christoph Hellwig
2021-06-25  8:25   ` Michal Hocko
2021-06-25 11:21     ` Matthew Wilcox
2021-06-25 13:21       ` Michal Hocko
2021-06-22 12:15 ` [PATCH v2 16/46] mm/memcg: Add folio_migrate_cgroup() Matthew Wilcox (Oracle)
2021-06-23  8:19   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 17/46] mm/memcg: Convert mem_cgroup_track_foreign_dirty_slowpath() to folio Matthew Wilcox (Oracle)
2021-06-23  8:21   ` Christoph Hellwig
2021-06-24 17:37     ` Matthew Wilcox
2021-06-28  6:24       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 18/46] mm/migrate: Add folio_migrate_mapping() Matthew Wilcox (Oracle)
2021-06-23  8:22   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 19/46] mm/migrate: Add folio_migrate_flags() Matthew Wilcox (Oracle)
2021-06-23  8:28   ` Christoph Hellwig
2021-06-24 17:55     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 20/46] mm/migrate: Add folio_migrate_copy() Matthew Wilcox (Oracle)
2021-06-23  8:35   ` Christoph Hellwig
2021-06-24 18:02     ` Matthew Wilcox
2021-06-28  6:26       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 21/46] mm/writeback: Rename __add_wb_stat() to wb_stat_mod() Matthew Wilcox (Oracle)
2021-06-23  8:37   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 22/46] flex_proportions: Allow N events instead of 1 Matthew Wilcox (Oracle)
2021-06-23  8:41   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 23/46] mm/writeback: Change __wb_writeout_inc() to __wb_writeout_add() Matthew Wilcox (Oracle)
2021-06-23  8:45   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 24/46] mm/writeback: Add __folio_end_writeback() Matthew Wilcox (Oracle)
2021-06-23  9:15   ` Christoph Hellwig
2021-06-24 18:20     ` Matthew Wilcox
2021-06-28  6:33       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 25/46] mm/writeback: Add folio_start_writeback() Matthew Wilcox (Oracle)
2021-06-23  9:18   ` Christoph Hellwig
2021-06-24 18:33     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 26/46] mm/writeback: Add folio_mark_dirty() Matthew Wilcox (Oracle)
2021-06-23  9:21   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 27/46] mm/writeback: Add __folio_mark_dirty() Matthew Wilcox (Oracle)
2021-06-23  9:27   ` Christoph Hellwig
2021-06-24 18:37     ` Matthew Wilcox
2021-06-28  6:03       ` Christoph Hellwig
2021-06-28 15:43         ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 28/46] mm/writeback: Add filemap_dirty_folio() Matthew Wilcox (Oracle)
2021-06-23  9:32   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 29/46] mm/writeback: Add folio_account_cleaned() Matthew Wilcox (Oracle)
2021-06-23  9:36   ` Christoph Hellwig
2021-06-24 20:06     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 30/46] mm/writeback: Add folio_cancel_dirty() Matthew Wilcox (Oracle)
2021-06-23  9:39   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 31/46] mm/writeback: Add folio_clear_dirty_for_io() Matthew Wilcox (Oracle)
2021-06-23  9:43   ` Christoph Hellwig
2021-06-24 20:09     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 32/46] mm/writeback: Add folio_account_redirty() Matthew Wilcox (Oracle)
2021-06-23  9:44   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 33/46] mm/writeback: Add folio_redirty_for_writepage() Matthew Wilcox (Oracle)
2021-06-23  9:45   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 34/46] mm/filemap: Add i_blocks_per_folio() Matthew Wilcox (Oracle)
2021-06-23  9:46   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 35/46] mm/filemap: Add folio_mkwrite_check_truncate() Matthew Wilcox (Oracle)
2021-06-23  9:47   ` Christoph Hellwig
2021-06-23 13:19     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 36/46] mm/filemap: Add readahead_folio() Matthew Wilcox (Oracle)
2021-06-23  9:50   ` Christoph Hellwig
2021-06-24 23:46     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 37/46] mm/workingset: Convert workingset_refault() to take a folio Matthew Wilcox (Oracle)
2021-06-23  9:52   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 38/46] mm: Add folio_evictable() Matthew Wilcox (Oracle)
2021-06-23  9:54   ` Christoph Hellwig
2021-06-24 23:50     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 39/46] mm/lru: Convert __pagevec_lru_add_fn to take a folio Matthew Wilcox (Oracle)
2021-06-23  9:55   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 40/46] mm/lru: Add folio_add_lru() Matthew Wilcox (Oracle)
2021-06-23  9:56   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 41/46] mm/page_alloc: Add folio allocation functions Matthew Wilcox (Oracle)
2021-06-23  9:58   ` Christoph Hellwig
2021-06-25  1:06     ` Matthew Wilcox
2021-06-22 12:15 ` [PATCH v2 42/46] mm/filemap: Add filemap_alloc_folio Matthew Wilcox (Oracle)
2021-06-23  9:59   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 43/46] mm/filemap: Add filemap_add_folio Matthew Wilcox (Oracle)
2021-06-23 11:30   ` Christoph Hellwig
2021-06-25  1:57     ` Matthew Wilcox
2021-06-22 12:15 ` Matthew Wilcox (Oracle) [this message]
2021-06-23 11:32   ` [PATCH v2 44/46] mm/filemap: Convert mapping_get_entry to return a folio Christoph Hellwig
2021-06-25  3:29     ` Matthew Wilcox
2021-06-28  6:07       ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 45/46] mm/filemap: Add filemap_get_folio Matthew Wilcox (Oracle)
2021-06-23 11:39   ` Christoph Hellwig
2021-06-22 12:15 ` [PATCH v2 46/46] mm/filemap: Add FGP_STABLE Matthew Wilcox (Oracle)
2021-06-23 11:43   ` Christoph Hellwig
2021-06-23 12:15     ` Matthew Wilcox

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210622121551.3398730-45-willy@infradead.org \
    --to=willy@infradead.org \
    --cc=akpm@linux-foundation.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.