bcachefs: Allocator prefers not to expand mi.btree_allocated bitmap

We now have a small bitmap in the member info section of the superblock
for "regions that have btree nodes", so that if we ever have to scan for
btree nodes in repair we don't have to scan the whole device(s).

This tweaks the allocator to prefer allocating from regions that are
already marked in this bitmap.

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

diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c
index 9fbd0d97f68cc6aa888785f0ea1e180b7d2e60f3..927a5f300b30e8ce7b3a9c3ba5d83c5ede8ba86a 100644 (file)
--- a/fs/bcachefs/alloc_foreground.c
+++ b/fs/bcachefs/alloc_foreground.c
@@ -71,7 +71,7 @@ void bch2_reset_alloc_cursors(struct bch_fs *c)
 {
        rcu_read_lock();
        for_each_member_device_rcu(c, ca, NULL)
-               ca->alloc_cursor = 0;
+               memset(ca->alloc_cursor, 0, sizeof(ca->alloc_cursor));
        rcu_read_unlock();
 }
 
@@ -389,7 +389,8 @@ bch2_bucket_alloc_early(struct btree_trans *trans,
        struct bkey_s_c k, ck;
        struct open_bucket *ob = NULL;
        u64 first_bucket = max_t(u64, ca->mi.first_bucket, ca->new_fs_bucket_idx);
-       u64 alloc_start = max(first_bucket, READ_ONCE(ca->alloc_cursor));
+       u64 *dev_alloc_cursor = &ca->alloc_cursor[s->btree_bitmap];
+       u64 alloc_start = max(first_bucket, *dev_alloc_cursor);
        u64 alloc_cursor = alloc_start;
        int ret;
 
@@ -405,8 +406,7 @@ bch2_bucket_alloc_early(struct btree_trans *trans,
 again:
        for_each_btree_key_norestart(trans, iter, BTREE_ID_alloc, POS(ca->dev_idx, alloc_cursor),
                           BTREE_ITER_slots, k, ret) {
-               struct bch_alloc_v4 a_convert;
-               const struct bch_alloc_v4 *a;
+               u64 bucket = k.k->p.offset;
 
                if (bkey_ge(k.k->p, POS(ca->dev_idx, ca->mi.nbuckets)))
                        break;
@@ -415,7 +415,24 @@ again:
                    is_superblock_bucket(ca, k.k->p.offset))
                        continue;
 
-               a = bch2_alloc_to_v4(k, &a_convert);
+               if (s->btree_bitmap != BTREE_BITMAP_ANY &&
+                   s->btree_bitmap != bch2_dev_btree_bitmap_marked_sectors(ca,
+                               bucket_to_sector(ca, bucket), ca->mi.bucket_size)) {
+                       if (s->btree_bitmap == BTREE_BITMAP_YES &&
+                           bucket_to_sector(ca, bucket) > 64ULL << ca->mi.btree_bitmap_shift)
+                               break;
+
+                       bucket = sector_to_bucket(ca,
+                                       round_up(bucket_to_sector(ca, bucket) + 1,
+                                                1ULL << ca->mi.btree_bitmap_shift));
+                       bch2_btree_iter_set_pos(&iter, POS(ca->dev_idx, bucket));
+                       s->buckets_seen++;
+                       s->skipped_mi_btree_bitmap++;
+                       continue;
+               }
+
+               struct bch_alloc_v4 a_convert;
+               const struct bch_alloc_v4 *a = bch2_alloc_to_v4(k, &a_convert);
                if (a->data_type != BCH_DATA_free)
                        continue;
 
@@ -441,7 +458,6 @@ next:
        bch2_trans_iter_exit(trans, &iter);
 
        alloc_cursor = iter.pos.offset;
-       ca->alloc_cursor = alloc_cursor;
 
        if (!ob && ret)
                ob = ERR_PTR(ret);
@@ -451,6 +467,8 @@ next:
                goto again;
        }
 
+       *dev_alloc_cursor = alloc_cursor;
+
        return ob;
 }
 
@@ -463,7 +481,8 @@ static struct open_bucket *bch2_bucket_alloc_freelist(struct btree_trans *trans,
        struct btree_iter iter;
        struct bkey_s_c k;
        struct open_bucket *ob = NULL;
-       u64 alloc_start = max_t(u64, ca->mi.first_bucket, READ_ONCE(ca->alloc_cursor));
+       u64 *dev_alloc_cursor = &ca->alloc_cursor[s->btree_bitmap];
+       u64 alloc_start = max_t(u64, ca->mi.first_bucket, READ_ONCE(*dev_alloc_cursor));
        u64 alloc_cursor = alloc_start;
        int ret;
 
@@ -485,6 +504,26 @@ again:
 
                        s->buckets_seen++;
 
+                       u64 bucket = alloc_cursor & ~(~0ULL << 56);
+                       if (s->btree_bitmap != BTREE_BITMAP_ANY &&
+                           s->btree_bitmap != bch2_dev_btree_bitmap_marked_sectors(ca,
+                                       bucket_to_sector(ca, bucket), ca->mi.bucket_size)) {
+                               if (s->btree_bitmap == BTREE_BITMAP_YES &&
+                                   bucket_to_sector(ca, bucket) > 64ULL << ca->mi.btree_bitmap_shift)
+                                       goto fail;
+
+                               bucket = sector_to_bucket(ca,
+                                               round_up(bucket_to_sector(ca, bucket) + 1,
+                                                        1ULL << ca->mi.btree_bitmap_shift));
+                               u64 genbits = alloc_cursor >> 56;
+                               alloc_cursor = bucket | (genbits << 56);
+
+                               if (alloc_cursor > k.k->p.offset)
+                                       bch2_btree_iter_set_pos(&iter, POS(ca->dev_idx, alloc_cursor));
+                               s->skipped_mi_btree_bitmap++;
+                               continue;
+                       }
+
                        ob = try_alloc_bucket(trans, ca, watermark,
                                              alloc_cursor, s, k, cl);
                        if (ob) {
@@ -496,10 +535,9 @@ again:
                if (ob || ret)
                        break;
        }
+fail:
        bch2_trans_iter_exit(trans, &iter);
 
-       ca->alloc_cursor = alloc_cursor;
-
        if (!ob && ret)
                ob = ERR_PTR(ret);
 
@@ -508,6 +546,8 @@ again:
                goto again;
        }
 
+       *dev_alloc_cursor = alloc_cursor;
+
        return ob;
 }
 
@@ -537,6 +577,7 @@ static noinline void trace_bucket_alloc2(struct bch_fs *c, struct bch_dev *ca,
        prt_printf(&buf, "need journal commit\t%llu\n", s->skipped_need_journal_commit);
        prt_printf(&buf, "nocow\t%llu\n",       s->skipped_nocow);
        prt_printf(&buf, "nouse\t%llu\n",       s->skipped_nouse);
+       prt_printf(&buf, "mi_btree_bitmap\t%llu\n", s->skipped_mi_btree_bitmap);
 
        if (!IS_ERR(ob)) {
                prt_printf(&buf, "allocated\t%llu\n", ob->bucket);
@@ -571,7 +612,9 @@ static struct open_bucket *bch2_bucket_alloc_trans(struct btree_trans *trans,
        struct open_bucket *ob = NULL;
        bool freespace = READ_ONCE(ca->mi.freespace_initialized);
        u64 avail;
-       struct bucket_alloc_state s = { 0 };
+       struct bucket_alloc_state s = {
+               .btree_bitmap = data_type == BCH_DATA_btree,
+       };
        bool waiting = false;
 again:
        bch2_dev_usage_read_fast(ca, usage);
@@ -609,6 +652,11 @@ alloc:
        if (s.skipped_need_journal_commit * 2 > avail)
                bch2_journal_flush_async(&c->journal, NULL);
 
+       if (!ob && s.btree_bitmap != BTREE_BITMAP_ANY) {
+               s.btree_bitmap = BTREE_BITMAP_ANY;
+               goto alloc;
+       }
+
        if (!ob && freespace && c->curr_recovery_pass <= BCH_RECOVERY_PASS_check_alloc_info) {
                freespace = false;
                goto alloc;

diff --git a/fs/bcachefs/alloc_types.h b/fs/bcachefs/alloc_types.h
index c2226e947c41fbcd7e462a7baa49d8726de44ecc..9bbb28e90b934fa27618537e85c901e0bf8efbda 100644 (file)
--- a/fs/bcachefs/alloc_types.h
+++ b/fs/bcachefs/alloc_types.h
@@ -9,11 +9,18 @@
 #include "fifo.h"
 
 struct bucket_alloc_state {
+       enum {
+               BTREE_BITMAP_NO,
+               BTREE_BITMAP_YES,
+               BTREE_BITMAP_ANY,
+       }       btree_bitmap;
+
        u64     buckets_seen;
        u64     skipped_open;
        u64     skipped_need_journal_commit;
        u64     skipped_nocow;
        u64     skipped_nouse;
+       u64     skipped_mi_btree_bitmap;
 };
 
 #define BCH_WATERMARKS()               \

diff --git a/fs/bcachefs/bcachefs.h b/fs/bcachefs/bcachefs.h
index ab415f0dd14ee05bba0a2b170d1ffe97f86a397c..ab2dc2c70da21a0473353fa55288042a5420bd00 100644 (file)
--- a/fs/bcachefs/bcachefs.h
+++ b/fs/bcachefs/bcachefs.h
@@ -587,7 +587,7 @@ struct bch_dev {
 
        /* Allocator: */
        u64                     new_fs_bucket_idx;
-       u64                     alloc_cursor;
+       u64                     alloc_cursor[3];
 
        unsigned                nr_open_buckets;
        unsigned                nr_btree_reserve;