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authorMatthew Wilcox <willy@infradead.org>2023-08-21 18:08:47 +0200
committerAndrew Morton <akpm@linux-foundation.org>2023-08-24 16:20:28 -0700
commit85a1333417a7561c1d10a77d6c873a37e6ea63a0 (patch)
tree148d430e6fa824c59aedca49b711d7fd5f792cce
parentcfeed8ffe55b37fa10286aaaa1369da00cb88440 (diff)
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: Matthew Wilcox <willy@infradead.org> Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Chris 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: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--include/linux/mm_types.h23
-rw-r--r--include/linux/swap.h5
2 files changed, 15 insertions, 13 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 55cd4bc57b8d..36c5b43999e6 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -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;
- void *private;
+ 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.
diff --git a/include/linux/swap.h b/include/linux/swap.h
index e5cf58a1cf9e..352eca0a75bc 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -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 */