bcachefs: Change copygc to consider bucket fragmentation

When devices have different sized buckets this is more correct.

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

diff --git a/fs/bcachefs/buckets_types.h b/fs/bcachefs/buckets_types.h
index 0f7fcfe29e0e3b9ef4c15009c799580aeb5f66bb..26779e94a18958deedfaed73f2c422bc1fa32e66 100644 (file)
--- a/fs/bcachefs/buckets_types.h
+++ b/fs/bcachefs/buckets_types.h
@@ -123,6 +123,7 @@ struct disk_reservation {
 struct copygc_heap_entry {
        u8                      dev;
        u8                      gen;
+       u16                     fragmentation;
        u32                     sectors;
        u64                     offset;
 };

diff --git a/fs/bcachefs/movinggc.c b/fs/bcachefs/movinggc.c
index 25ae4e195c15b46a89e59d3724d540222ff106e5..5f96f619bee0c3b7005a7f9e6506839fa9719c8c 100644 (file)
--- a/fs/bcachefs/movinggc.c
+++ b/fs/bcachefs/movinggc.c
@@ -44,13 +44,6 @@
 #define COPYGC_BUCKETS_PER_ITER(ca)                                    \
        ((ca)->free[RESERVE_MOVINGGC].size / 2)
 
-static inline int sectors_used_cmp(copygc_heap *heap,
-                                  struct copygc_heap_entry l,
-                                  struct copygc_heap_entry r)
-{
-       return cmp_int(l.sectors, r.sectors);
-}
-
 static int bucket_offset_cmp(const void *_l, const void *_r, size_t size)
 {
        const struct copygc_heap_entry *l = _l;
@@ -123,6 +116,13 @@ static bool have_copygc_reserve(struct bch_dev *ca)
        return ret;
 }
 
+static inline int fragmentation_cmp(copygc_heap *heap,
+                                  struct copygc_heap_entry l,
+                                  struct copygc_heap_entry r)
+{
+       return cmp_int(l.fragmentation, r.fragmentation);
+}
+
 static int bch2_copygc(struct bch_fs *c)
 {
        copygc_heap *h = &c->copygc_heap;
@@ -180,10 +180,12 @@ static int bch2_copygc(struct bch_fs *c)
                        e = (struct copygc_heap_entry) {
                                .dev            = dev_idx,
                                .gen            = m.gen,
+                               .fragmentation  = bucket_sectors_used(m) * (1U << 15)
+                                       / ca->mi.bucket_size,
                                .sectors        = bucket_sectors_used(m),
                                .offset         = bucket_to_sector(ca, b),
                        };
-                       heap_add_or_replace(h, e, -sectors_used_cmp, NULL);
+                       heap_add_or_replace(h, e, -fragmentation_cmp, NULL);
                }
                up_read(&ca->bucket_lock);
        }
@@ -197,7 +199,7 @@ static int bch2_copygc(struct bch_fs *c)
                sectors_to_move += i->sectors;
 
        while (sectors_to_move > sectors_reserved) {
-               BUG_ON(!heap_pop(h, e, -sectors_used_cmp, NULL));
+               BUG_ON(!heap_pop(h, e, -fragmentation_cmp, NULL));
                sectors_to_move -= e.sectors;
        }