Commit 73ffa530 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: Drop journal entry compaction 



Previously, we dropped empty journal entries and coalesced entries that
could be - but it's not worth the overhead; we very rarely leave unused
journal entries after getting a journal reservation.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 67997234

fs/bcachefs/journal_io.c

+2 −24
Original line number Diff line number Diff line
@@ -1725,7 +1725,7 @@ static CLOSURE_CALLBACK(do_journal_write) 
static int bch2_journal_write_prep(struct journal *j, struct journal_buf *w)

{

	struct bch_fs *c = container_of(j, struct bch_fs, journal);

	struct jset_entry *start, *end, *i, *next, *prev = NULL;

	struct jset_entry *start, *end, *i;

	struct jset *jset = w->data;

	struct journal_keys_to_wb wb = { NULL };

	unsigned sectors, bytes, u64s;
@@ -1742,7 +1742,7 @@ static int bch2_journal_write_prep(struct journal *j, struct journal_buf *w) 
	 * If we wanted to be really fancy here, we could sort all the keys in

	 * the jset and drop keys that were overwritten - probably not worth it:

	 */

	vstruct_for_each_safe(jset, i, next) {

	vstruct_for_each(jset, i) {

		unsigned u64s = le16_to_cpu(i->u64s);



		/* Empty entry: */
@@ -1782,34 +1782,12 @@ static int bch2_journal_write_prep(struct journal *j, struct journal_buf *w) 
			i->type = BCH_JSET_ENTRY_btree_keys;

			break;

		}



		/* Can we merge with previous entry? */

		if (prev &&

		    i->btree_id == prev->btree_id &&

		    i->level	== prev->level &&

		    i->type	== prev->type &&

		    i->type	== BCH_JSET_ENTRY_btree_keys &&

		    le16_to_cpu(prev->u64s) + u64s <= U16_MAX) {

			memmove_u64s_down(vstruct_next(prev),

					  i->_data,

					  u64s);

			le16_add_cpu(&prev->u64s, u64s);

			continue;

		}



		/* Couldn't merge, move i into new position (after prev): */

		prev = prev ? vstruct_next(prev) : jset->start;

		if (i != prev)

			memmove_u64s_down(prev, i, jset_u64s(u64s));

	}



	if (wb.wb)

		bch2_journal_keys_to_write_buffer_end(c, &wb);

	w->need_flush_to_write_buffer = false;



	prev = prev ? vstruct_next(prev) : jset->start;

	jset->u64s = cpu_to_le32((u64 *) prev - jset->_data);



	start = end = vstruct_last(jset);



	end	= bch2_btree_roots_to_journal_entries(c, end, btree_roots_have);