diff mbox series

[v3,2/6] mm: add private field of first tail to struct page and struct folio

Message ID 20220908193706.1716548-3-sidhartha.kumar@oracle.com (mailing list archive)
State New
Headers show
Series begin converting hugetlb code to folios | expand

Commit Message

Sidhartha Kumar Sept. 8, 2022, 7:37 p.m. UTC 
Allows struct folio to store hugetlb metadata that is contained in the
private field of the first tail page. On 32-bit, _private_1 aligns with
page[1].private.

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
 include/linux/mm_types.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

Comments

Mike Kravetz Sept. 19, 2022, 10:14 p.m. UTC | #1 
On 09/08/22 12:37, Sidhartha Kumar wrote:
> Allows struct folio to store hugetlb metadata that is contained in the
> private field of the first tail page. On 32-bit, _private_1 aligns with
> page[1].private.
> 
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
> ---
>  include/linux/mm_types.h | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)

This change is fine with me as it makes the following patches dealing
with hugetlb page subpool folio aware.  I 'think' Matthew is OK with
this direction, but it would be good if he chimed in.

Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
diff mbox series

Patch

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 8a9ee9d24973..7a33171a05b6 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -143,6 +143,7 @@  struct page {
 			atomic_t compound_pincount;
 #ifdef CONFIG_64BIT
 			unsigned int compound_nr; /* 1 << compound_order */
+			unsigned long _private_1;
 #endif
 		};
 		struct {	/* Second tail page of compound page */
@@ -251,6 +252,7 @@  struct page {
  * @_total_mapcount: Do not use directly, call folio_entire_mapcount().
  * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
  * @_folio_nr_pages: Do not use directly, call folio_nr_pages().
+ * @_private_1: Do not use directly, call folio_get_private_1().
  *
  * A folio is a physically, virtually and logically contiguous set
  * of bytes.  It is a power-of-two in size, and it is aligned to that
@@ -298,6 +300,7 @@  struct folio {
 #ifdef CONFIG_64BIT
 	unsigned int _folio_nr_pages;
 #endif
+	unsigned long _private_1;
 };
 
 #define FOLIO_MATCH(pg, fl)						\
@@ -325,6 +328,7 @@  FOLIO_MATCH(compound_mapcount, _total_mapcount);
 FOLIO_MATCH(compound_pincount, _pincount);
 #ifdef CONFIG_64BIT
 FOLIO_MATCH(compound_nr, _folio_nr_pages);
+FOLIO_MATCH(_private_1, _private_1);
 #endif
 #undef FOLIO_MATCH
 
@@ -370,6 +374,16 @@  static inline void *folio_get_private(struct folio *folio)
 	return folio->private;
 }
 
+static inline void folio_set_private_1(struct folio *folio, unsigned long private)
+{
+	folio->_private_1 = private;
+}
+
+static inline unsigned long folio_get_private_1(struct folio *folio)
+{
+	return folio->_private_1;
+}
+
 struct page_frag_cache {
 	void * va;
 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)