bcachefs: Fragmentation LRU

Now that we have much more efficient updates to the LRU btree, this
patch adds a new LRU that indexes buckets by fragmentation.

This means copygc no longer has to scan every bucket to find buckets
that need to be evacuated.

Changes:
 - A new field in bch_alloc_v4, fragmentation_lru - this corresponds to
   the bucket's position in the fragmentation LRU. We add a new field
   for this instead of calculating it as needed because we may make the
   fragmentation LRU optional; this field indicates whether a bucket is
   on the fragmentation LRU.

   Also, zoned devices will introduce variable bucket sizes; explicitly
   recording the LRU position will be safer for them.

 - A new copygc path for using the fragmentation LRU instead of
   scanning every bucket and building up an in-memory heap.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 0 insertions, 11 deletions

diff --git a/fs/bcachefs/buckets_types.h b/fs/bcachefs/buckets_types.h
index 1dbba7d906dd..2a9dab9006ef 100644
--- a/fs/bcachefs/buckets_types.h
+++ b/fs/bcachefs/buckets_types.h
@@ -89,15 +89,4 @@ struct disk_reservation {
 	unsigned		nr_replicas;
 };
 
-struct copygc_heap_entry {
-	u8			dev;
-	u8			gen;
-	u8			replicas;
-	u32			fragmentation;
-	u32			sectors;
-	u64			bucket;
-};
-
-typedef HEAP(struct copygc_heap_entry) copygc_heap;
-
 #endif /* _BUCKETS_TYPES_H */