Re: linux-next: manual merge of the kvm tree with the vfs-brauner tree

Stephen Rothwell
2023-12-04T00:51:52Z

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Hi all,

On Wed, 22 Nov 2023 12:55:39 +1100 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> Today's linux-next merge of the kvm tree got a conflict in:
>
> include/linux/pagemap.h
>
> between commit:
>
> 762321dab9a7 ("filemap: add a per-mapping stable writes flag")

This is now in Linus' tree.

> from the vfs-brauner tree and commit:
>
> 0003e2a41468 ("mm: Add AS_UNMOVABLE to mark mapping as completely unmovable")
>
> from the kvm tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.

The current resolution is below.

--
Cheers,
Stephen Rothwell

diff --cc include/linux/pagemap.h
index 06142ff7f9ce,bf2965b01b35..c2d90588c0bf
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@@ -203,9 -203,8 +203,10 @@@ enum mapping_flags
/* writeback related tags are not used */
AS_NO_WRITEBACK_TAGS = 5,
AS_LARGE_FOLIO_SUPPORT = 6,
- AS_RELEASE_ALWAYS = 7, /* Call ->release_folio(), even if no private data */
- AS_UNMOVABLE = 8, /* The mapping cannot be moved, ever */
+ AS_RELEASE_ALWAYS, /* Call ->release_folio(), even if no private data */
+ AS_STABLE_WRITES, /* must wait for writeback before modifying
+ folio contents */
++ AS_UNMOVABLE, /* The mapping cannot be moved, ever */
};

/**
@@@ -291,21 -290,22 +292,37 @@@ static inline void mapping_clear_releas
clear_bit(AS_RELEASE_ALWAYS, &mapping->flags);
}

+ static inline void mapping_set_unmovable(struct address_space *mapping)
+ {
+ /*
+ * It's expected unmovable mappings are also unevictable. Compaction
+ * migrate scanner (isolate_migratepages_block()) relies on this to
+ * reduce page locking.
+ */
+ set_bit(AS_UNEVICTABLE, &mapping->flags);
+ set_bit(AS_UNMOVABLE, &mapping->flags);
+ }
+
+ static inline bool mapping_unmovable(struct address_space *mapping)
+ {
+ return test_bit(AS_UNMOVABLE, &mapping->flags);
+ }
+
+static inline bool mapping_stable_writes(const struct address_space *mapping)
+{
+ return test_bit(AS_STABLE_WRITES, &mapping->flags);
+}
+
+static inline void mapping_set_stable_writes(struct address_space *mapping)
+{
+ set_bit(AS_STABLE_WRITES, &mapping->flags);
+}
+
+static inline void mapping_clear_stable_writes(struct address_space *mapping)
+{
+ clear_bit(AS_STABLE_WRITES, &mapping->flags);
+}
+
static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
{
return mapping->gfp_mask;