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: [PATCH v3 01/25] mm: Introduce struct folio
Date: Thu, 28 Jan 2021 07:03:40 +0000 [thread overview]
Message-ID: <20210128070404.1922318-2-willy@infradead.org> (raw)
In-Reply-To: <20210128070404.1922318-1-willy@infradead.org>
We have trouble keeping track of whether we've already called
compound_head() to ensure we're not operating on a tail page. Further,
it's never clear whether we intend a struct page to refer to PAGE_SIZE
bytes or page_size(compound_head(page)).
Introduce a new type 'struct folio' that always refers to an entire
(possibly compound) page, and points to the head page (or base page).
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
include/linux/mm.h | 26 ++++++++++++++++++++++++++
include/linux/mm_types.h | 17 +++++++++++++++++
2 files changed, 43 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2d6e715ab8ea..f20504017adf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -924,6 +924,11 @@ static inline unsigned int compound_order(struct page *page)
return page[1].compound_order;
}
+static inline unsigned int folio_order(struct folio *folio)
+{
+ return compound_order(&folio->page);
+}
+
static inline bool hpage_pincount_available(struct page *page)
{
/*
@@ -975,6 +980,26 @@ static inline unsigned int page_shift(struct page *page)
void free_compound_page(struct page *page);
+static inline unsigned long folio_nr_pages(struct folio *folio)
+{
+ return compound_nr(&folio->page);
+}
+
+static inline struct folio *next_folio(struct folio *folio)
+{
+ return folio + folio_nr_pages(folio);
+}
+
+static inline unsigned int folio_shift(struct folio *folio)
+{
+ return PAGE_SHIFT + folio_order(folio);
+}
+
+static inline size_t folio_size(struct folio *folio)
+{
+ return PAGE_SIZE << folio_order(folio);
+}
+
#ifdef CONFIG_MMU
/*
* Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
@@ -1618,6 +1643,7 @@ extern void pagefault_out_of_memory(void);
#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
#define offset_in_thp(page, p) ((unsigned long)(p) & (thp_size(page) - 1))
+#define offset_in_folio(folio, p) ((unsigned long)(p) & (folio_size(folio) - 1))
/*
* Flags passed to show_mem() and show_free_areas() to suppress output in
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 07d9acb5b19c..875dc6cd6ad2 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -223,6 +223,23 @@ struct page {
#endif
} _struct_page_alignment;
+/*
+ * A struct folio is either a base (order-0) page or the head page of
+ * a compound page.
+ */
+struct folio {
+ struct page page;
+};
+
+static inline struct folio *page_folio(struct page *page)
+{
+ unsigned long head = READ_ONCE(page->compound_head);
+
+ if (unlikely(head & 1))
+ return (struct folio *)(head - 1);
+ return (struct folio *)page;
+}
+
static inline atomic_t *compound_mapcount_ptr(struct page *page)
{
return &page[1].compound_mapcount;
--
2.29.2
next prev parent reply other threads:[~2021-01-28 7:04 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-28 7:03 [PATCH v3 00/25] Page folios Matthew Wilcox (Oracle)
2021-01-28 7:03 ` Matthew Wilcox (Oracle) [this message]
2021-03-01 20:26 ` [PATCH v3 01/25] mm: Introduce struct folio Zi Yan
2021-03-01 20:53 ` Matthew Wilcox
2021-03-01 21:03 ` Zi Yan
2021-01-28 7:03 ` [PATCH v3 02/25] mm: Add folio_pgdat Matthew Wilcox (Oracle)
2021-03-01 21:05 ` Zi Yan
2021-01-28 7:03 ` [PATCH v3 03/25] mm/vmstat: Add folio stat wrappers Matthew Wilcox (Oracle)
2021-03-01 21:17 ` Zi Yan
2021-03-01 22:15 ` Matthew Wilcox
2021-01-28 7:03 ` [PATCH v3 04/25] mm/debug: Add VM_BUG_ON_FOLIO and VM_WARN_ON_ONCE_FOLIO Matthew Wilcox (Oracle)
2021-03-01 21:25 ` Zi Yan
2021-01-28 7:03 ` [PATCH v3 05/25] mm: Add put_folio Matthew Wilcox (Oracle)
2021-03-01 21:41 ` Zi Yan
2021-01-28 7:03 ` [PATCH v3 06/25] mm: Add get_folio Matthew Wilcox (Oracle)
2021-03-01 21:45 ` Zi Yan
2021-01-28 7:03 ` [PATCH v3 07/25] mm: Create FolioFlags Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 08/25] mm: Handle per-folio private data Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 09/25] mm: Add folio_index, folio_page and folio_contains Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 10/25] mm/util: Add folio_mapping and folio_file_mapping Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 11/25] mm/memcg: Add folio_memcg, lock_folio_memcg and unlock_folio_memcg Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 12/25] mm/memcg: Add mem_cgroup_folio_lruvec Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 13/25] mm: Add unlock_folio Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 14/25] mm: Add lock_folio Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 15/25] mm: Add lock_folio_killable Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 16/25] mm: Convert lock_page_async to lock_folio_async Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 17/25] mm/filemap: Convert end_page_writeback to end_folio_writeback Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 18/25] mm: Convert wait_on_page_bit to wait_on_folio_bit Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 19/25] mm: Add wait_for_stable_folio and wait_on_folio_writeback Matthew Wilcox (Oracle)
2021-01-28 7:03 ` [PATCH v3 20/25] mm: Add wait_on_folio_locked & wait_on_folio_locked_killable Matthew Wilcox (Oracle)
2021-01-28 7:04 ` [PATCH v3 21/25] mm: Convert lock_page_or_retry to lock_folio_or_retry Matthew Wilcox (Oracle)
2021-01-28 7:04 ` [PATCH v3 22/25] mm/filemap: Convert wake_up_page_bit to wake_up_folio_bit Matthew Wilcox (Oracle)
2021-01-28 7:04 ` [PATCH v3 23/25] mm: Convert test_clear_page_writeback to test_clear_folio_writeback Matthew Wilcox (Oracle)
2021-01-28 7:04 ` [PATCH v3 24/25] mm/filemap: Convert page wait queues to be folios Matthew Wilcox (Oracle)
2021-01-28 7:04 ` [PATCH v3 25/25] cachefiles: Switch to wait_page_key Matthew Wilcox (Oracle)
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