Commit 19b22d04 authored by Kent Overstreet's avatar Kent Overstreet
Browse files

bcachefs: Don't set btree nodes as accessed on fill 



Prevent jobs that do lots of scanning (i.e. evacuatee, scrub) from
causing OOMs.

The shrinker code seems to be having issues when it doesn't do any
freeing because it's just flipping off the acccessed bit - and the
accessed bit shouldn't be set on first use anyways.

Signed-off-by: default avatarKent Overstreet <kent.overstreet@linux.dev>
parent 7b6759b1

fs/bcachefs/btree_cache.c

+4 −5
Original line number Diff line number Diff line
@@ -852,7 +852,6 @@ struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_rea 
	b->sib_u64s[1]		= 0;

	b->whiteout_u64s	= 0;

	bch2_btree_keys_init(b);

	set_btree_node_accessed(b);



	bch2_time_stats_update(&c->times[BCH_TIME_btree_node_mem_alloc],

			       start_time);
@@ -1286,6 +1285,10 @@ struct btree *bch2_btree_node_get_noiter(struct btree_trans *trans, 
			six_unlock_read(&b->c.lock);

			goto retry;

		}



		/* avoid atomic set bit if it's not needed: */

		if (!btree_node_accessed(b))

			set_btree_node_accessed(b);

	}



	/* XXX: waiting on IO with btree locks held: */
@@ -1301,10 +1304,6 @@ struct btree *bch2_btree_node_get_noiter(struct btree_trans *trans, 
		prefetch(p + L1_CACHE_BYTES * 2);

	}



	/* avoid atomic set bit if it's not needed: */

	if (!btree_node_accessed(b))

		set_btree_node_accessed(b);



	if (unlikely(btree_node_read_error(b))) {

		six_unlock_read(&b->c.lock);

		b = ERR_PTR(-BCH_ERR_btree_node_read_err_cached);