bcache: Rework allocator reserves
We need a reserve for allocating buckets for new btree nodes - and now that
we've got multiple btrees, it really needs to be per btree.
This reworks the reserves so we've got separate freelists for each reserve
instead of watermarks, which seems to make things a bit cleaner, and it adds
some code so that btree_split() can make sure the reserve is available before it
starts.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 101231f..6a0f5fa 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -167,6 +167,8 @@
_r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__); \
} \
rw_unlock(_w, _b); \
+ if (_r == -EINTR) \
+ schedule(); \
bch_cannibalize_unlock(c); \
if (_r == -ENOSPC) { \
wait_event((c)->try_wait, \
@@ -175,6 +177,7 @@
} \
} while (_r == -EINTR); \
\
+ finish_wait(&(c)->bucket_wait, &(op)->wait); \
_r; \
})
@@ -1075,7 +1078,7 @@
mutex_lock(&c->bucket_lock);
retry:
- if (__bch_bucket_alloc_set(c, WATERMARK_METADATA, &k.key, 1, wait))
+ if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, wait))
goto err;
bkey_put(c, &k.key);
@@ -1132,6 +1135,28 @@
atomic_inc(&b->c->prio_blocked);
}
+static int btree_check_reserve(struct btree *b, struct btree_op *op)
+{
+ struct cache_set *c = b->c;
+ struct cache *ca;
+ unsigned i, reserve = c->root->level * 2 + 1;
+ int ret = 0;
+
+ mutex_lock(&c->bucket_lock);
+
+ for_each_cache(ca, c, i)
+ if (fifo_used(&ca->free[RESERVE_BTREE]) < reserve) {
+ if (op)
+ prepare_to_wait(&c->bucket_wait, &op->wait,
+ TASK_UNINTERRUPTIBLE);
+ ret = -EINTR;
+ break;
+ }
+
+ mutex_unlock(&c->bucket_lock);
+ return ret;
+}
+
/* Garbage collection */
uint8_t __bch_btree_mark_key(struct cache_set *c, int level, struct bkey *k)
@@ -1428,7 +1453,8 @@
if (!IS_ERR(last->b)) {
should_rewrite = btree_gc_mark_node(last->b, gc);
- if (should_rewrite) {
+ if (should_rewrite &&
+ !btree_check_reserve(b, NULL)) {
n = btree_node_alloc_replacement(last->b,
false);
@@ -2071,6 +2097,10 @@
closure_init_stack(&cl);
bch_keylist_init(&parent_keys);
+ if (!b->level &&
+ btree_check_reserve(b, op))
+ return -EINTR;
+
n1 = btree_node_alloc_replacement(b, true);
if (IS_ERR(n1))
goto err;