diff options
| author | Sean Christopherson <seanjc@google.com> | 2023-10-27 11:21:56 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2023-11-13 05:31:38 -0500 |
| commit | 0003e2a414687fff6a75250d381e4abf345d663f (patch) | |
| tree | 7eca3e93819013585f28865630a850a57cc03a91 /mm/migrate.c | |
| parent | 5a475554db1e476a14216e742ea2bdb77362d5d5 (diff) | |
mm: Add AS_UNMOVABLE to mark mapping as completely unmovable
Add an "unmovable" flag for mappings that cannot be migrated under any
circumstance. KVM will use the flag for its upcoming GUEST_MEMFD support,
which will not support compaction/migration, at least not in the
foreseeable future.
Test AS_UNMOVABLE under folio lock as already done for the async
compaction/dirty folio case, as the mapping can be removed by truncation
while compaction is running. To avoid having to lock every folio with a
mapping, assume/require that unmovable mappings are also unevictable, and
have mapping_set_unmovable() also set AS_UNEVICTABLE.
Cc: Matthew Wilcox <willy@infradead.org>
Co-developed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20231027182217.3615211-15-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 06086dc9da28..60f2ff6b36aa 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -956,6 +956,8 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, if (!mapping) rc = migrate_folio(mapping, dst, src, mode); + else if (mapping_unmovable(mapping)) + rc = -EOPNOTSUPP; else if (mapping->a_ops->migrate_folio) /* * Most folios have a mapping and most filesystems |