Commit 2177147b authored by Kent Overstreet's avatar Kent Overstreet Committed by Kent Overstreet
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bcachefs: Improve bset compaction 



The previous patch that fixed btree nodes being written too aggressively
now meant that we weren't sorting btree node bsets optimally - this
patch fixes that.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 241e2636

fs/bcachefs/btree_cache.c

+1 −1
Original line number Diff line number Diff line
@@ -215,7 +215,7 @@ static int __btree_node_reclaim(struct bch_fs *c, struct btree *b, bool flush) 
		if (bch2_verify_btree_ondisk)

			bch2_btree_node_write(c, b, SIX_LOCK_intent);

		else

			__bch2_btree_node_write(c, b, SIX_LOCK_read);

			__bch2_btree_node_write(c, b);



		/* wait for any in flight btree write */

		btree_node_wait_on_io(b);

fs/bcachefs/btree_io.c

+34 −17
Original line number Diff line number Diff line
@@ -241,7 +241,6 @@ bool bch2_compact_whiteouts(struct bch_fs *c, struct btree *b, 
}



static void btree_node_sort(struct bch_fs *c, struct btree *b,

			    struct btree_iter *iter,

			    unsigned start_idx,

			    unsigned end_idx,

			    bool filter_whiteouts)
@@ -377,8 +376,7 @@ void bch2_btree_sort_into(struct bch_fs *c, 
 * We're about to add another bset to the btree node, so if there's currently

 * too many bsets - sort some of them together:

 */

static bool btree_node_compact(struct bch_fs *c, struct btree *b,

			       struct btree_iter *iter)

static bool btree_node_compact(struct bch_fs *c, struct btree *b)

{

	unsigned unwritten_idx;

	bool ret = false;
@@ -390,13 +388,13 @@ static bool btree_node_compact(struct bch_fs *c, struct btree *b, 
			break;



	if (b->nsets - unwritten_idx > 1) {

		btree_node_sort(c, b, iter, unwritten_idx,

		btree_node_sort(c, b, unwritten_idx,

				b->nsets, false);

		ret = true;

	}



	if (unwritten_idx > 1) {

		btree_node_sort(c, b, iter, 0, unwritten_idx, false);

		btree_node_sort(c, b, 0, unwritten_idx, false);

		ret = true;

	}
@@ -426,12 +424,30 @@ void bch2_btree_init_next(struct bch_fs *c, struct btree *b, 
			  struct btree_iter *iter)

{

	struct btree_node_entry *bne;

	bool did_sort;

	bool reinit_iter = false;



	EBUG_ON(!(b->c.lock.state.seq & 1));

	EBUG_ON(iter && iter->l[b->c.level].b != b);

	BUG_ON(bset_written(b, bset(b, &b->set[1])));



	if (b->nsets == MAX_BSETS) {

		unsigned log_u64s[] = {

			ilog2(bset_u64s(&b->set[0])),

			ilog2(bset_u64s(&b->set[1])),

			ilog2(bset_u64s(&b->set[2])),

		};



		if (log_u64s[1] >= (log_u64s[0] + log_u64s[2]) / 2) {

			bch2_btree_node_write(c, b, SIX_LOCK_write);

			reinit_iter = true;

		}

	}



	if (b->nsets == MAX_BSETS &&

	    btree_node_compact(c, b))

		reinit_iter = true;



	did_sort = btree_node_compact(c, b, iter);

	BUG_ON(b->nsets >= MAX_BSETS);



	bne = want_new_bset(c, b);

	if (bne)
@@ -439,7 +455,7 @@ void bch2_btree_init_next(struct bch_fs *c, struct btree *b, 


	bch2_btree_build_aux_trees(b);



	if (iter && did_sort)

	if (iter && reinit_iter)

		bch2_btree_iter_reinit_node(iter, b);

}
@@ -1324,8 +1340,7 @@ static int validate_bset_for_write(struct bch_fs *c, struct btree *b, 
	return ret;

}



void __bch2_btree_node_write(struct bch_fs *c, struct btree *b,

			    enum six_lock_type lock_type_held)

void __bch2_btree_node_write(struct bch_fs *c, struct btree *b)

{

	struct btree_write_bio *wbio;

	struct bset_tree *t;
@@ -1596,7 +1611,7 @@ bool bch2_btree_post_write_cleanup(struct bch_fs *c, struct btree *b) 
	 * single bset:

	 */

	if (b->nsets > 1) {

		btree_node_sort(c, b, NULL, 0, b->nsets, true);

		btree_node_sort(c, b, 0, b->nsets, true);

		invalidated_iter = true;

	} else {

		invalidated_iter = bch2_drop_whiteouts(b, COMPACT_ALL);
@@ -1628,11 +1643,10 @@ bool bch2_btree_post_write_cleanup(struct bch_fs *c, struct btree *b) 
void bch2_btree_node_write(struct bch_fs *c, struct btree *b,

			   enum six_lock_type lock_type_held)

{

	BUG_ON(lock_type_held == SIX_LOCK_write);



	if (lock_type_held == SIX_LOCK_intent ||

	    six_lock_tryupgrade(&b->c.lock)) {

		__bch2_btree_node_write(c, b, SIX_LOCK_intent);

	    (lock_type_held == SIX_LOCK_read &&

	     six_lock_tryupgrade(&b->c.lock))) {

		__bch2_btree_node_write(c, b);



		/* don't cycle lock unnecessarily: */

		if (btree_node_just_written(b) &&
@@ -1644,7 +1658,10 @@ void bch2_btree_node_write(struct bch_fs *c, struct btree *b, 
		if (lock_type_held == SIX_LOCK_read)

			six_lock_downgrade(&b->c.lock);

	} else {

		__bch2_btree_node_write(c, b, SIX_LOCK_read);

		__bch2_btree_node_write(c, b);

		if (lock_type_held == SIX_LOCK_write &&

		    btree_node_just_written(b))

			bch2_btree_post_write_cleanup(c, b);

	}

}

fs/bcachefs/btree_io.h

+1 −2
Original line number Diff line number Diff line
@@ -144,8 +144,7 @@ void bch2_btree_complete_write(struct bch_fs *, struct btree *, 
			      struct btree_write *);

void bch2_btree_write_error_work(struct work_struct *);



void __bch2_btree_node_write(struct bch_fs *, struct btree *,

			    enum six_lock_type);

void __bch2_btree_node_write(struct bch_fs *, struct btree *);

bool bch2_btree_post_write_cleanup(struct bch_fs *, struct btree *);



void bch2_btree_node_write(struct bch_fs *, struct btree *,

fs/bcachefs/btree_update_interior.h

+3 −1
Original line number Diff line number Diff line
@@ -256,13 +256,15 @@ static inline size_t bch_btree_keys_u64s_remaining(struct bch_fs *c, 
	return remaining;

}



#define BTREE_WRITE_SET_U64s_BITS	9



static inline unsigned btree_write_set_buffer(struct btree *b)

{

	/*

	 * Could buffer up larger amounts of keys for btrees with larger keys,

	 * pending benchmarking:

	 */

	return 4 << 10;

	return 8 << BTREE_WRITE_SET_U64s_BITS;

}



static inline struct btree_node_entry *want_new_bset(struct bch_fs *c,