linux/fs/bcachefs/lru.h
Kent Overstreet 80c3308578 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>
2023-10-22 17:09:53 -04:00

62 lines
1.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_LRU_H
#define _BCACHEFS_LRU_H
#define LRU_TIME_BITS 48
#define LRU_TIME_MAX ((1ULL << LRU_TIME_BITS) - 1)
static inline struct bpos lru_pos(u16 lru_id, u64 dev_bucket, u64 time)
{
EBUG_ON(time > LRU_TIME_MAX);
return POS(((u64) lru_id << LRU_TIME_BITS)|time, dev_bucket);
}
static inline u64 lru_pos_id(struct bpos pos)
{
return pos.inode >> LRU_TIME_BITS;
}
static inline u64 lru_pos_time(struct bpos pos)
{
return pos.inode & ~(~0ULL << LRU_TIME_BITS);
}
#define BCH_LRU_TYPES() \
x(read) \
x(fragmentation)
enum bch_lru_type {
#define x(n) BCH_LRU_##n,
BCH_LRU_TYPES()
#undef x
};
#define BCH_LRU_FRAGMENTATION_START ((1U << 16) - 1)
static inline enum bch_lru_type lru_type(struct bkey_s_c l)
{
u16 lru_id = l.k->p.inode >> 48;
if (lru_id == BCH_LRU_FRAGMENTATION_START)
return BCH_LRU_fragmentation;
return BCH_LRU_read;
}
int bch2_lru_invalid(const struct bch_fs *, struct bkey_s_c, unsigned, struct printbuf *);
void bch2_lru_to_text(struct printbuf *, struct bch_fs *, struct bkey_s_c);
void bch2_lru_pos_to_text(struct printbuf *, struct bpos);
#define bch2_bkey_ops_lru ((struct bkey_ops) { \
.key_invalid = bch2_lru_invalid, \
.val_to_text = bch2_lru_to_text, \
})
int bch2_lru_del(struct btree_trans *, u16, u64, u64);
int bch2_lru_set(struct btree_trans *, u16, u64, u64);
int bch2_lru_change(struct btree_trans *, u16, u64, u64, u64);
int bch2_check_lrus(struct bch_fs *);
#endif /* _BCACHEFS_LRU_H */