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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: akpm@linux-foundation.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org, Vlastimil Babka <vbabka@suse.cz>,
	William Kucharski <william.kucharski@oracle.com>,
	Christoph Hellwig <hch@lst.de>,
	David Howells <dhowells@redhat.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCH v13 32/32] mm: Add folio_mapped()
Date: Mon, 12 Jul 2021 20:02:04 +0100	[thread overview]
Message-ID: <20210712190204.80979-33-willy@infradead.org> (raw)
In-Reply-To: <20210712190204.80979-1-willy@infradead.org>

This function is the equivalent of page_mapped().  It is slightly
shorter as we do not need to handle the PageTail() case.  Reimplement
page_mapped() as a wrapper around folio_mapped().  folio_mapped()
is 13 bytes smaller than page_mapped(), but the page_mapped() wrapper
is 30 bytes, for a net increase of 17 bytes of text.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/mm.h       |  1 +
 include/linux/mm_types.h |  6 ++++++
 mm/folio-compat.c        |  6 ++++++
 mm/util.c                | 29 ++++++++++++++++-------------
 4 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 24311e4c08e9..a856c078e040 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1766,6 +1766,7 @@ static inline pgoff_t page_index(struct page *page)
 }
 
 bool page_mapped(struct page *page);
+bool folio_mapped(struct folio *folio);
 
 /*
  * Return true only if the page has been allocated with
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index c15b4af8ef4d..d0061ddf080f 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -291,6 +291,12 @@ FOLIO_MATCH(memcg_data, memcg_data);
 #endif
 #undef FOLIO_MATCH
 
+static inline atomic_t *folio_mapcount_ptr(struct folio *folio)
+{
+	struct page *tail = &folio->page + 1;
+	return &tail->compound_mapcount;
+}
+
 static inline atomic_t *compound_mapcount_ptr(struct page *page)
 {
 	return &page[1].compound_mapcount;
diff --git a/mm/folio-compat.c b/mm/folio-compat.c
index 3c83f03b80d7..7044fcc8a8aa 100644
--- a/mm/folio-compat.c
+++ b/mm/folio-compat.c
@@ -35,3 +35,9 @@ void wait_for_stable_page(struct page *page)
 	return folio_wait_stable(page_folio(page));
 }
 EXPORT_SYMBOL_GPL(wait_for_stable_page);
+
+bool page_mapped(struct page *page)
+{
+	return folio_mapped(page_folio(page));
+}
+EXPORT_SYMBOL(page_mapped);
diff --git a/mm/util.c b/mm/util.c
index d6176bb63629..0c65b260cded 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -652,28 +652,31 @@ void *page_rmapping(struct page *page)
 	return __page_rmapping(page);
 }
 
-/*
- * Return true if this page is mapped into pagetables.
- * For compound page it returns true if any subpage of compound page is mapped.
+/**
+ * folio_mapped - Is this folio mapped into userspace?
+ * @folio: The folio.
+ *
+ * Return: True if any page in this folio is referenced by user page tables.
  */
-bool page_mapped(struct page *page)
+bool folio_mapped(struct folio *folio)
 {
-	int i;
+	int i, nr;
 
-	if (likely(!PageCompound(page)))
-		return atomic_read(&page->_mapcount) >= 0;
-	page = compound_head(page);
-	if (atomic_read(compound_mapcount_ptr(page)) >= 0)
+	if (folio_single(folio))
+		return atomic_read(&folio->_mapcount) >= 0;
+	if (atomic_read(folio_mapcount_ptr(folio)) >= 0)
 		return true;
-	if (PageHuge(page))
+	if (folio_hugetlb(folio))
 		return false;
-	for (i = 0; i < compound_nr(page); i++) {
-		if (atomic_read(&page[i]._mapcount) >= 0)
+
+	nr = folio_nr_pages(folio);
+	for (i = 0; i < nr; i++) {
+		if (atomic_read(&folio_page(folio, i)->_mapcount) >= 0)
 			return true;
 	}
 	return false;
 }
-EXPORT_SYMBOL(page_mapped);
+EXPORT_SYMBOL(folio_mapped);
 
 struct anon_vma *page_anon_vma(struct page *page)
 {
-- 
2.30.2


      parent reply	other threads:[~2021-07-12 19:21 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-12 19:01 [PATCH v13a 00/32] Memory folios Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 01/32] mm: Convert get_page_unless_zero() to return bool Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 02/32] mm: Introduce struct folio Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 03/32] mm: Add folio_pgdat(), folio_zone() and folio_zonenum() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 04/32] mm/vmstat: Add functions to account folio statistics Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 05/32] mm/debug: Add VM_BUG_ON_FOLIO() and VM_WARN_ON_ONCE_FOLIO() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 06/32] mm: Add folio reference count functions Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 07/32] mm: Add folio_put() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 08/32] mm: Add folio_get() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 09/32] mm: Add folio_try_get_rcu() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 10/32] mm: Add folio flag manipulation functions Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 11/32] mm/lru: Add folio LRU functions Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 12/32] mm: Handle per-folio private data Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 13/32] mm/filemap: Add folio_index(), folio_file_page() and folio_contains() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 14/32] mm/filemap: Add folio_next_index() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 15/32] mm/filemap: Add folio_pos() and folio_file_pos() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 16/32] mm/util: Add folio_mapping() and folio_file_mapping() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 17/32] mm/filemap: Add folio_unlock() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 18/32] mm/filemap: Add folio_lock() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 19/32] mm/filemap: Add folio_lock_killable() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 20/32] mm/filemap: Add __folio_lock_async() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 21/32] mm/filemap: Add folio_wait_locked() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 22/32] mm/filemap: Add __folio_lock_or_retry() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 23/32] mm/swap: Add folio_rotate_reclaimable() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 24/32] mm/filemap: Add folio_end_writeback() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 25/32] mm/writeback: Add folio_wait_writeback() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 26/32] mm/writeback: Add folio_wait_stable() Matthew Wilcox (Oracle)
2021-07-12 19:01 ` [PATCH v13 27/32] mm/filemap: Add folio_wait_bit() Matthew Wilcox (Oracle)
2021-07-12 19:02 ` [PATCH v13 28/32] mm/filemap: Add folio_wake_bit() Matthew Wilcox (Oracle)
2021-07-12 19:02 ` [PATCH v13 29/32] mm/filemap: Convert page wait queues to be folios Matthew Wilcox (Oracle)
2021-07-12 19:02 ` [PATCH v13 30/32] mm/filemap: Add folio private_2 functions Matthew Wilcox (Oracle)
2021-07-12 19:02 ` [PATCH v13 31/32] fs/netfs: Add folio fscache functions Matthew Wilcox (Oracle)
2021-07-12 19:02 ` Matthew Wilcox (Oracle) [this message]

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