bcachefs: Don't use BTREE_INSERT_USE_RESERVE so much

Previously, we were using BTREE_INSERT_RESERVE in a lot of places where
it no longer makes sense.

 - we now have more open_buckets than we used to, and the reserves work
   better, so we shouldn't need to use BTREE_INSERT_RESERVE just because
   we're holding open_buckets pinned anymore.

 - We have the btree key cache for updates to the alloc btree, meaning
   we no longer need the btree reserve to ensure the allocator can make
   forward progress.

This means that we should only need a reserve for btree updates to
ensure that copygc can make forward progress.

Since it's now just for copygc, we can also fold RESERVE_BTREE into
RESERVE_MOVINGGC (the allocator's freelist reserve).

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

15 files changed, 20 insertions, 62 deletions

diff --git a/fs/bcachefs/alloc_background.c b/fs/bcachefs/alloc_background.c
index 62ca9b7aaefa..36409b599847 100644
--- a/fs/bcachefs/alloc_background.c
+++ b/fs/bcachefs/alloc_background.c
@@ -319,9 +319,7 @@ retry:
 	bch2_trans_update(trans, iter, &a->k_i,
 			  BTREE_TRIGGER_NORUN);
 	ret = bch2_trans_commit(trans, NULL, NULL,
-				BTREE_INSERT_NOFAIL|
-				BTREE_INSERT_USE_RESERVE|
-				flags);
+				BTREE_INSERT_NOFAIL|flags);
 err:
 	if (ret == -EINTR)
 		goto retry;
@@ -575,8 +573,7 @@ static int wait_buckets_available(struct bch_fs *c, struct bch_dev *ca)
 
 		if (available > fifo_free(&ca->free_inc) ||
 		    (available &&
-		     (!fifo_full(&ca->free[RESERVE_BTREE]) ||
-		      !fifo_full(&ca->free[RESERVE_MOVINGGC]))))
+		     !fifo_full(&ca->free[RESERVE_MOVINGGC])))
 			break;
 
 		up_read(&c->gc_lock);
@@ -977,8 +974,7 @@ retry:
 				BTREE_INSERT_NOUNLOCK|
 				BTREE_INSERT_NOCHECK_RW|
 				BTREE_INSERT_NOFAIL|
-				BTREE_INSERT_USE_RESERVE|
-				BTREE_INSERT_USE_ALLOC_RESERVE|
+				BTREE_INSERT_JOURNAL_RESERVED|
 				flags);
 	if (ret == -EINTR)
 		goto retry;
diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c
index 7a92e3d53254..5432a8dae719 100644
--- a/fs/bcachefs/alloc_foreground.c
+++ b/fs/bcachefs/alloc_foreground.c
@@ -204,10 +204,8 @@ success:
 static inline unsigned open_buckets_reserved(enum alloc_reserve reserve)
 {
 	switch (reserve) {
-	case RESERVE_ALLOC:
+	case RESERVE_MOVINGGC:
 		return 0;
-	case RESERVE_BTREE:
-		return OPEN_BUCKETS_COUNT / 4;
 	default:
 		return OPEN_BUCKETS_COUNT / 2;
 	}
@@ -263,16 +261,6 @@ struct open_bucket *bch2_bucket_alloc(struct bch_fs *c, struct bch_dev *ca,
 		goto out;
 
 	switch (reserve) {
-	case RESERVE_ALLOC:
-		if (fifo_pop(&ca->free[RESERVE_BTREE], bucket))
-			goto out;
-		break;
-	case RESERVE_BTREE:
-		if (fifo_used(&ca->free[RESERVE_BTREE]) * 2 >=
-		    ca->free[RESERVE_BTREE].size &&
-		    fifo_pop(&ca->free[RESERVE_BTREE], bucket))
-			goto out;
-		break;
 	case RESERVE_MOVINGGC:
 		if (fifo_pop(&ca->free[RESERVE_MOVINGGC], bucket))
 			goto out;
diff --git a/fs/bcachefs/alloc_types.h b/fs/bcachefs/alloc_types.h
index 20705460bb0a..a510ca9a295b 100644
--- a/fs/bcachefs/alloc_types.h
+++ b/fs/bcachefs/alloc_types.h
@@ -37,11 +37,9 @@ struct bucket_clock {
 /* There is one reserve for each type of btree, one for prios and gens
  * and one for moving GC */
 enum alloc_reserve {
-	RESERVE_ALLOC		= -1,
-	RESERVE_BTREE		= 0,
-	RESERVE_MOVINGGC	= 1,
-	RESERVE_NONE		= 2,
-	RESERVE_NR		= 3,
+	RESERVE_MOVINGGC	= 0,
+	RESERVE_NONE		= 1,
+	RESERVE_NR		= 2,
 };
 
 typedef FIFO(long)	alloc_fifo;
diff --git a/fs/bcachefs/btree_gc.c b/fs/bcachefs/btree_gc.c
index 6268ea637d19..d0a856ec60e3 100644
--- a/fs/bcachefs/btree_gc.c
+++ b/fs/bcachefs/btree_gc.c
@@ -233,7 +233,6 @@ static int bch2_gc_btree(struct bch_fs *c, enum btree_id btree_id,
 			if (max_stale > 64)
 				bch2_btree_node_rewrite(c, iter,
 						b->data->keys.seq,
-						BTREE_INSERT_USE_RESERVE|
 						BTREE_INSERT_NOWAIT|
 						BTREE_INSERT_GC_LOCK_HELD);
 			else if (!bch2_btree_gc_rewrite_disabled &&
diff --git a/fs/bcachefs/btree_key_cache.c b/fs/bcachefs/btree_key_cache.c
index 1a557b753bc1..4357aefdb668 100644
--- a/fs/bcachefs/btree_key_cache.c
+++ b/fs/bcachefs/btree_key_cache.c
@@ -349,8 +349,6 @@ retry:
 				  BTREE_INSERT_NOUNLOCK|
 				  BTREE_INSERT_NOCHECK_RW|
 				  BTREE_INSERT_NOFAIL|
-				  BTREE_INSERT_USE_RESERVE|
-				  BTREE_INSERT_USE_ALLOC_RESERVE|
 				  BTREE_INSERT_JOURNAL_RESERVED|
 				  BTREE_INSERT_JOURNAL_RECLAIM);
 err:
diff --git a/fs/bcachefs/btree_update.h b/fs/bcachefs/btree_update.h
index adb07043cbb3..a25138080169 100644
--- a/fs/bcachefs/btree_update.h
+++ b/fs/bcachefs/btree_update.h
@@ -20,7 +20,6 @@ enum btree_insert_flags {
 	__BTREE_INSERT_NOCHECK_RW,
 	__BTREE_INSERT_LAZY_RW,
 	__BTREE_INSERT_USE_RESERVE,
-	__BTREE_INSERT_USE_ALLOC_RESERVE,
 	__BTREE_INSERT_JOURNAL_REPLAY,
 	__BTREE_INSERT_JOURNAL_RESERVED,
 	__BTREE_INSERT_JOURNAL_RECLAIM,
@@ -43,7 +42,6 @@ enum btree_insert_flags {
 
 /* for copygc, or when merging btree nodes */
 #define BTREE_INSERT_USE_RESERVE	(1 << __BTREE_INSERT_USE_RESERVE)
-#define BTREE_INSERT_USE_ALLOC_RESERVE	(1 << __BTREE_INSERT_USE_ALLOC_RESERVE)
 
 /* Insert is for journal replay - don't get journal reservations: */
 #define BTREE_INSERT_JOURNAL_REPLAY	(1 << __BTREE_INSERT_JOURNAL_REPLAY)
diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index 8f96756ba648..8c7f7a8b5375 100644
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -201,12 +201,9 @@ static struct btree *__bch2_btree_node_alloc(struct bch_fs *c,
 	unsigned nr_reserve;
 	enum alloc_reserve alloc_reserve;
 
-	if (flags & BTREE_INSERT_USE_ALLOC_RESERVE) {
+	if (flags & BTREE_INSERT_USE_RESERVE) {
 		nr_reserve	= 0;
-		alloc_reserve	= RESERVE_ALLOC;
-	} else if (flags & BTREE_INSERT_USE_RESERVE) {
-		nr_reserve	= BTREE_NODE_RESERVE / 2;
-		alloc_reserve	= RESERVE_BTREE;
+		alloc_reserve	= RESERVE_MOVINGGC;
 	} else {
 		nr_reserve	= BTREE_NODE_RESERVE;
 		alloc_reserve	= RESERVE_NONE;
@@ -577,8 +574,6 @@ static void btree_update_nodes_written(struct btree_update *as)
 	bch2_trans_init(&trans, c, 0, 512);
 	ret = __bch2_trans_do(&trans, &as->disk_res, &journal_seq,
 			      BTREE_INSERT_NOFAIL|
-			      BTREE_INSERT_USE_RESERVE|
-			      BTREE_INSERT_USE_ALLOC_RESERVE|
 			      BTREE_INSERT_NOCHECK_RW|
 			      BTREE_INSERT_JOURNAL_RECLAIM|
 			      BTREE_INSERT_JOURNAL_RESERVED,
@@ -1457,15 +1452,6 @@ int bch2_btree_split_leaf(struct bch_fs *c, struct btree_iter *iter,
 	struct btree_update *as;
 	struct closure cl;
 	int ret = 0;
-	struct btree_insert_entry *i;
-
-	/*
-	 * We already have a disk reservation and open buckets pinned; this
-	 * allocation must not block:
-	 */
-	trans_for_each_update(trans, i)
-		if (btree_node_type_needs_gc(i->iter->btree_id))
-			flags |= BTREE_INSERT_USE_RESERVE;
 
 	closure_init_stack(&cl);
 
@@ -1926,10 +1912,7 @@ int bch2_btree_node_update_key(struct bch_fs *c, struct btree_iter *iter,
 retry:
 	as = bch2_btree_update_start(iter->trans, iter->btree_id,
 		parent ? btree_update_reserve_required(c, parent) : 0,
-		BTREE_INSERT_NOFAIL|
-		BTREE_INSERT_USE_RESERVE|
-		BTREE_INSERT_USE_ALLOC_RESERVE,
-		&cl);
+		BTREE_INSERT_NOFAIL, &cl);
 
 	if (IS_ERR(as)) {
 		ret = PTR_ERR(as);
diff --git a/fs/bcachefs/btree_update_leaf.c b/fs/bcachefs/btree_update_leaf.c
index c77e243b2a04..c490df4709ba 100644
--- a/fs/bcachefs/btree_update_leaf.c
+++ b/fs/bcachefs/btree_update_leaf.c
@@ -1084,8 +1084,7 @@ int bch2_btree_delete_at(struct btree_trans *trans,
 
 	bch2_trans_update(trans, iter, &k, 0);
 	return bch2_trans_commit(trans, NULL, NULL,
-				 BTREE_INSERT_NOFAIL|
-				 BTREE_INSERT_USE_RESERVE|flags);
+				 BTREE_INSERT_NOFAIL|flags);
 }
 
 int bch2_btree_delete_range_trans(struct btree_trans *trans, enum btree_id id,
diff --git a/fs/bcachefs/buckets.c b/fs/bcachefs/buckets.c
index 1934b845ea15..8bbf958d64e4 100644
--- a/fs/bcachefs/buckets.c
+++ b/fs/bcachefs/buckets.c
@@ -2192,7 +2192,7 @@ int bch2_dev_buckets_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
 			     ca->mi.bucket_size / c->opts.btree_node_size);
 	/* XXX: these should be tunable */
 	size_t reserve_none	= max_t(size_t, 1, nbuckets >> 9);
-	size_t copygc_reserve	= max_t(size_t, 2, nbuckets >> 7);
+	size_t copygc_reserve	= max_t(size_t, 2, nbuckets >> 6);
 	size_t free_inc_nr	= max(max_t(size_t, 1, nbuckets >> 12),
 				      btree_reserve * 2);
 	bool resize = ca->buckets[0] != NULL;
@@ -2209,7 +2209,6 @@ int bch2_dev_buckets_resize(struct bch_fs *c, struct bch_dev *ca, u64 nbuckets)
 	    !(buckets_nouse	= kvpmalloc(BITS_TO_LONGS(nbuckets) *
 					    sizeof(unsigned long),
 					    GFP_KERNEL|__GFP_ZERO)) ||
-	    !init_fifo(&free[RESERVE_BTREE], btree_reserve, GFP_KERNEL) ||
 	    !init_fifo(&free[RESERVE_MOVINGGC],
 		       copygc_reserve, GFP_KERNEL) ||
 	    !init_fifo(&free[RESERVE_NONE], reserve_none, GFP_KERNEL) ||
diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
index 8f39c4de6672..0b65a4cf0f48 100644
--- a/fs/bcachefs/ec.c
+++ b/fs/bcachefs/ec.c
@@ -800,8 +800,7 @@ static int ec_stripe_update_ptrs(struct bch_fs *c,
 		bch2_trans_update(&trans, iter, sk.k, 0);
 
 		ret = bch2_trans_commit(&trans, NULL, NULL,
-					BTREE_INSERT_NOFAIL|
-					BTREE_INSERT_USE_RESERVE);
+					BTREE_INSERT_NOFAIL);
 		if (ret == -EINTR)
 			ret = 0;
 		if (ret)
diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c
index 9211364c3e99..91135d00bedf 100644
--- a/fs/bcachefs/io.c
+++ b/fs/bcachefs/io.c
@@ -320,8 +320,7 @@ int bch2_extent_update(struct btree_trans *trans,
 
 	ret = bch2_trans_commit(trans, disk_res, journal_seq,
 				BTREE_INSERT_NOCHECK_RW|
-				BTREE_INSERT_NOFAIL|
-				BTREE_INSERT_USE_RESERVE);
+				BTREE_INSERT_NOFAIL);
 	if (ret)
 		return ret;
 
diff --git a/fs/bcachefs/journal.c b/fs/bcachefs/journal.c
index d54424829378..56b750c50fbd 100644
--- a/fs/bcachefs/journal.c
+++ b/fs/bcachefs/journal.c
@@ -777,7 +777,7 @@ static int __bch2_set_nr_journal_buckets(struct bch_dev *ca, unsigned nr,
 			}
 		} else {
 			rcu_read_lock();
-			ob = bch2_bucket_alloc(c, ca, RESERVE_ALLOC,
+			ob = bch2_bucket_alloc(c, ca, RESERVE_NONE,
 					       false, cl);
 			rcu_read_unlock();
 			if (IS_ERR(ob)) {
diff --git a/fs/bcachefs/move.c b/fs/bcachefs/move.c
index 6242b7d91a00..48b47857acc4 100644
--- a/fs/bcachefs/move.c
+++ b/fs/bcachefs/move.c
@@ -168,7 +168,6 @@ static int bch2_migrate_index_update(struct bch_write_op *op)
 		ret = bch2_trans_commit(&trans, &op->res,
 				op_journal_seq(op),
 				BTREE_INSERT_NOFAIL|
-				BTREE_INSERT_USE_RESERVE|
 				m->data_opts.btree_insert_flags);
 		if (!ret)
 			atomic_long_inc(&c->extent_migrate_done);
diff --git a/fs/bcachefs/movinggc.c b/fs/bcachefs/movinggc.c
index 2c5daed58aca..efa7f38ecec6 100644
--- a/fs/bcachefs/movinggc.c
+++ b/fs/bcachefs/movinggc.c
@@ -200,6 +200,11 @@ static int bch2_copygc(struct bch_fs *c)
 		return -1;
 	}
 
+	/*
+	 * Our btree node allocations also come out of RESERVE_MOVINGGC:
+	 */
+	sectors_to_move = (sectors_to_move * 3) / 4;
+
 	for (i = h->data; i < h->data + h->used; i++)
 		sectors_to_move += i->sectors * i->replicas;
 
diff --git a/fs/bcachefs/sysfs.c b/fs/bcachefs/sysfs.c
index cc13fc258115..bfae0d7142e0 100644
--- a/fs/bcachefs/sysfs.c
+++ b/fs/bcachefs/sysfs.c
@@ -798,7 +798,6 @@ static void dev_alloc_debug_to_text(struct printbuf *out, struct bch_dev *ca)
 
 	pr_buf(out,
 		"free_inc:               %zu/%zu\n"
-		"free[RESERVE_BTREE]:    %zu/%zu\n"
 		"free[RESERVE_MOVINGGC]: %zu/%zu\n"
 		"free[RESERVE_NONE]:     %zu/%zu\n"
 		"buckets:\n"
@@ -827,7 +826,6 @@ static void dev_alloc_debug_to_text(struct printbuf *out, struct bch_dev *ca)
 		"open_buckets_user:      %u\n"
 		"btree reserve cache:    %u\n",
 		fifo_used(&ca->free_inc),		ca->free_inc.size,
-		fifo_used(&ca->free[RESERVE_BTREE]),	ca->free[RESERVE_BTREE].size,
 		fifo_used(&ca->free[RESERVE_MOVINGGC]),	ca->free[RESERVE_MOVINGGC].size,
 		fifo_used(&ca->free[RESERVE_NONE]),	ca->free[RESERVE_NONE].size,
 		ca->mi.nbuckets - ca->mi.first_bucket,