bcachefs: Prep work for variable size btree node buffers

bcachefs btree nodes are big - typically 256k - and btree roots are
pinned in memory. As we're now up to 18 btrees, we now have significant
memory overhead in mostly empty btree roots.

And in the future we're going to start enforcing that certain btree node
boundaries exist, to solve lock contention issues - analagous to XFS's
AGIs.

Thus, we need to start allocating smaller btree node buffers when we
can. This patch changes code that refers to the filesystem constant
c->opts.btree_node_size to refer to the btree node buffer size -
btree_buf_bytes() - where appropriate.

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

1 files changed, 19 insertions, 19 deletions

diff --git a/fs/bcachefs/btree_io.c b/fs/bcachefs/btree_io.c
index 33db48e2153f..aa9b6cbe3226 100644
--- a/fs/bcachefs/btree_io.c
+++ b/fs/bcachefs/btree_io.c
@@ -112,7 +112,7 @@ static void *btree_bounce_alloc(struct bch_fs *c, size_t size,
 	unsigned flags = memalloc_nofs_save();
 	void *p;
 
-	BUG_ON(size > btree_bytes(c));
+	BUG_ON(size > c->opts.btree_node_size);
 
 	*used_mempool = false;
 	p = vpmalloc(size, __GFP_NOWARN|GFP_NOWAIT);
@@ -174,8 +174,8 @@ static void bch2_sort_whiteouts(struct bch_fs *c, struct btree *b)
 
 	ptrs = ptrs_end = ((void *) new_whiteouts + bytes);
 
-	for (k = unwritten_whiteouts_start(c, b);
-	     k != unwritten_whiteouts_end(c, b);
+	for (k = unwritten_whiteouts_start(b);
+	     k != unwritten_whiteouts_end(b);
 	     k = bkey_p_next(k))
 		*--ptrs = k;
 
@@ -192,7 +192,7 @@ static void bch2_sort_whiteouts(struct bch_fs *c, struct btree *b)
 	verify_no_dups(b, new_whiteouts,
 		       (void *) ((u64 *) new_whiteouts + b->whiteout_u64s));
 
-	memcpy_u64s(unwritten_whiteouts_start(c, b),
+	memcpy_u64s(unwritten_whiteouts_start(b),
 		    new_whiteouts, b->whiteout_u64s);
 
 	btree_bounce_free(c, bytes, used_mempool, new_whiteouts);
@@ -313,7 +313,7 @@ static void btree_node_sort(struct bch_fs *c, struct btree *b,
 	}
 
 	bytes = sorting_entire_node
-		? btree_bytes(c)
+		? btree_buf_bytes(b)
 		: __vstruct_bytes(struct btree_node, u64s);
 
 	out = btree_bounce_alloc(c, bytes, &used_mempool);
@@ -338,7 +338,7 @@ static void btree_node_sort(struct bch_fs *c, struct btree *b,
 	if (sorting_entire_node) {
 		u64s = le16_to_cpu(out->keys.u64s);
 
-		BUG_ON(bytes != btree_bytes(c));
+		BUG_ON(bytes != btree_buf_bytes(b));
 
 		/*
 		 * Our temporary buffer is the same size as the btree node's
@@ -502,7 +502,7 @@ void bch2_btree_init_next(struct btree_trans *trans, struct btree *b)
 
 	bne = want_new_bset(c, b);
 	if (bne)
-		bch2_bset_init_next(c, b, bne);
+		bch2_bset_init_next(b, bne);
 
 	bch2_btree_build_aux_trees(b);
 
@@ -1160,7 +1160,7 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 			     ptr_written, b->written);
 	} else {
 		for (bne = write_block(b);
-		     bset_byte_offset(b, bne) < btree_bytes(c);
+		     bset_byte_offset(b, bne) < btree_buf_bytes(b);
 		     bne = (void *) bne + block_bytes(c))
 			btree_err_on(bne->keys.seq == b->data->keys.seq &&
 				     !bch2_journal_seq_is_blacklisted(c,
@@ -1172,7 +1172,7 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 				     "found bset signature after last bset");
 	}
 
-	sorted = btree_bounce_alloc(c, btree_bytes(c), &used_mempool);
+	sorted = btree_bounce_alloc(c, btree_buf_bytes(b), &used_mempool);
 	sorted->keys.u64s = 0;
 
 	set_btree_bset(b, b->set, &b->data->keys);
@@ -1188,7 +1188,7 @@ int bch2_btree_node_read_done(struct bch_fs *c, struct bch_dev *ca,
 
 	BUG_ON(b->nr.live_u64s != u64s);
 
-	btree_bounce_free(c, btree_bytes(c), used_mempool, sorted);
+	btree_bounce_free(c, btree_buf_bytes(b), used_mempool, sorted);
 
 	if (updated_range)
 		bch2_btree_node_drop_keys_outside_node(b);
@@ -1284,7 +1284,7 @@ static void btree_node_read_work(struct work_struct *work)
 		rb->have_ioref		= bch2_dev_get_ioref(ca, READ);
 		bio_reset(bio, NULL, REQ_OP_READ|REQ_SYNC|REQ_META);
 		bio->bi_iter.bi_sector	= rb->pick.ptr.offset;
-		bio->bi_iter.bi_size	= btree_bytes(c);
+		bio->bi_iter.bi_size	= btree_buf_bytes(b);
 
 		if (rb->have_ioref) {
 			bio_set_dev(bio, ca->disk_sb.bdev);
@@ -1512,7 +1512,7 @@ fsck_err:
 	}
 
 	if (best >= 0) {
-		memcpy(b->data, ra->buf[best], btree_bytes(c));
+		memcpy(b->data, ra->buf[best], btree_buf_bytes(b));
 		ret = bch2_btree_node_read_done(c, NULL, b, false, saw_error);
 	} else {
 		ret = -1;
@@ -1578,7 +1578,7 @@ static int btree_node_read_all_replicas(struct bch_fs *c, struct btree *b, bool
 	for (i = 0; i < ra->nr; i++) {
 		ra->buf[i] = mempool_alloc(&c->btree_bounce_pool, GFP_NOFS);
 		ra->bio[i] = bio_alloc_bioset(NULL,
-					      buf_pages(ra->buf[i], btree_bytes(c)),
+					      buf_pages(ra->buf[i], btree_buf_bytes(b)),
 					      REQ_OP_READ|REQ_SYNC|REQ_META,
 					      GFP_NOFS,
 					      &c->btree_bio);
@@ -1598,7 +1598,7 @@ static int btree_node_read_all_replicas(struct bch_fs *c, struct btree *b, bool
 		rb->pick		= pick;
 		rb->bio.bi_iter.bi_sector = pick.ptr.offset;
 		rb->bio.bi_end_io	= btree_node_read_all_replicas_endio;
-		bch2_bio_map(&rb->bio, ra->buf[i], btree_bytes(c));
+		bch2_bio_map(&rb->bio, ra->buf[i], btree_buf_bytes(b));
 
 		if (rb->have_ioref) {
 			this_cpu_add(ca->io_done->sectors[READ][BCH_DATA_btree],
@@ -1665,7 +1665,7 @@ void bch2_btree_node_read(struct btree_trans *trans, struct btree *b,
 	ca = bch_dev_bkey_exists(c, pick.ptr.dev);
 
 	bio = bio_alloc_bioset(NULL,
-			       buf_pages(b->data, btree_bytes(c)),
+			       buf_pages(b->data, btree_buf_bytes(b)),
 			       REQ_OP_READ|REQ_SYNC|REQ_META,
 			       GFP_NOFS,
 			       &c->btree_bio);
@@ -1679,7 +1679,7 @@ void bch2_btree_node_read(struct btree_trans *trans, struct btree *b,
 	INIT_WORK(&rb->work, btree_node_read_work);
 	bio->bi_iter.bi_sector	= pick.ptr.offset;
 	bio->bi_end_io		= btree_node_read_endio;
-	bch2_bio_map(bio, b->data, btree_bytes(c));
+	bch2_bio_map(bio, b->data, btree_buf_bytes(b));
 
 	if (rb->have_ioref) {
 		this_cpu_add(ca->io_done->sectors[READ][BCH_DATA_btree],
@@ -2074,8 +2074,8 @@ do_write:
 	i->u64s		= 0;
 
 	sort_iter_add(&sort_iter.iter,
-		      unwritten_whiteouts_start(c, b),
-		      unwritten_whiteouts_end(c, b));
+		      unwritten_whiteouts_start(b),
+		      unwritten_whiteouts_end(b));
 	SET_BSET_SEPARATE_WHITEOUTS(i, false);
 
 	b->whiteout_u64s = 0;
@@ -2251,7 +2251,7 @@ bool bch2_btree_post_write_cleanup(struct bch_fs *c, struct btree *b)
 
 	bne = want_new_bset(c, b);
 	if (bne)
-		bch2_bset_init_next(c, b, bne);
+		bch2_bset_init_next(b, bne);
 
 	bch2_btree_build_aux_trees(b);