From 0a63b66db566cffdf90182eb6e66fdd4d0479e63 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Mon, 17 Mar 2014 17:15:53 -0700 Subject: bcache: Rework btree cache reserve handling This changes the bucket allocation reserves to use _real_ reserves - separate freelists - instead of watermarks, which if nothing else makes the current code saner to reason about and is going to be important in the future when we add support for multiple btrees. It also adds btree_check_reserve(), which checks (and locks) the reserves for both bucket allocation and memory allocation for btree nodes; the old code just kinda sorta assumed that since (e.g. for btree node splits) it had the root locked and that meant no other threads could try to make use of the same reserve; this technically should have been ok for memory allocation (we should always have a reserve for memory allocation (the btree node cache is used as a reserve and we preallocate it)), but multiple btrees will mean that locking the root won't be sufficient anymore, and for the bucket allocation reserve it was technically possible for the old code to deadlock. Signed-off-by: Kent Overstreet --- drivers/md/bcache/btree.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/md/bcache/btree.h') diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h index acebf26809cc..3ce371fa7f98 100644 --- a/drivers/md/bcache/btree.h +++ b/drivers/md/bcache/btree.h @@ -242,8 +242,9 @@ void __bch_btree_node_write(struct btree *, struct closure *); void bch_btree_node_write(struct btree *, struct closure *); void bch_btree_set_root(struct btree *); -struct btree *bch_btree_node_alloc(struct cache_set *, int, bool); -struct btree *bch_btree_node_get(struct cache_set *, struct bkey *, int, bool); +struct btree *bch_btree_node_alloc(struct cache_set *, struct btree_op *, int); +struct btree *bch_btree_node_get(struct cache_set *, struct btree_op *, + struct bkey *, int, bool); int bch_btree_insert_check_key(struct btree *, struct btree_op *, struct bkey *); -- cgit v1.2.3