Commit 85a13334 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Andrew Morton
Browse files

mm/swap: use dedicated entry for swap in folio 

Let's stop working on the private field and use an explicit swap field. 
We have to move the swp_entry_t typedef.

Link: https://lkml.kernel.org/r/20230821160849.531668-3-david@redhat.com


Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarChris Li <chrisl@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent cfeed8ff

include/linux/mm_types.h

+13 −10
Original line number Diff line number Diff line
@@ -248,6 +248,14 @@ static inline struct page *encoded_page_ptr(struct encoded_page *page) 
	return (struct page *)(~ENCODE_PAGE_BITS & (unsigned long)page);

}



/*

 * A swap entry has to fit into a "unsigned long", as the entry is hidden

 * in the "index" field of the swapper address space.

 */

typedef struct {

	unsigned long val;

} swp_entry_t;



/**

 * struct folio - Represents a contiguous set of bytes.

 * @flags: Identical to the page flags.
@@ -258,7 +266,7 @@ static inline struct page *encoded_page_ptr(struct encoded_page *page) 
 * @index: Offset within the file, in units of pages.  For anonymous memory,

 *    this is the index from the beginning of the mmap.

 * @private: Filesystem per-folio data (see folio_attach_private()).

 *    Used for swp_entry_t if folio_test_swapcache().

 * @swap: Used for swp_entry_t if folio_test_swapcache().

 * @_mapcount: Do not access this member directly.  Use folio_mapcount() to

 *    find out how many times this folio is mapped by userspace.

 * @_refcount: Do not access this member directly.  Use folio_ref_count()
@@ -301,7 +309,10 @@ struct folio { 
			};

			struct address_space *mapping;

			pgoff_t index;

			union {

				void *private;

				swp_entry_t swap;

			};

			atomic_t _mapcount;

			atomic_t _refcount;

#ifdef CONFIG_MEMCG
@@ -1209,14 +1220,6 @@ enum tlb_flush_reason { 
	NR_TLB_FLUSH_REASONS,

};



 /*

  * A swap entry has to fit into a "unsigned long", as the entry is hidden

  * in the "index" field of the swapper address space.

  */

typedef struct {

	unsigned long val;

} swp_entry_t;



/**

 * enum fault_flag - Fault flag definitions.

 * @FAULT_FLAG_WRITE: Fault was a write fault.

include/linux/swap.h

+2 −3
Original line number Diff line number Diff line
@@ -335,8 +335,7 @@ struct swap_info_struct { 


static inline swp_entry_t folio_swap_entry(struct folio *folio)

{

	swp_entry_t entry = { .val = page_private(&folio->page) };

	return entry;

	return folio->swap;

}



static inline swp_entry_t page_swap_entry(struct page *page)
@@ -350,7 +349,7 @@ static inline swp_entry_t page_swap_entry(struct page *page) 


static inline void folio_set_swap_entry(struct folio *folio, swp_entry_t entry)

{

	folio->private = (void *)entry.val;

	folio->swap = entry;

}



/* linux/mm/workingset.c */