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bcachefs: Optimize btree_path_alloc()

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- move slowpath code to a separate function, btree_path_overflow()
 - no need to use hweight64
 - copy nr_max_paths from btree_transaction_stats to btree_trans,
   avoiding a data dependency in the fast path

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2022-09-26 16:19:56 -04:00
parent 14d8f26ad0
commit 3f3bc66ef0
1 changed files with 12 additions and 7 deletions
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19
fs/bcachefs/btree_iter.c
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@ -1408,7 +1408,8 @@ static void bch2_trans_update_max_paths(struct btree_trans *trans)
if (!buf.allocation_failure) {
mutex_lock(&s->lock);
if (s->nr_max_paths < hweight64(trans->paths_allocated)) {
s->nr_max_paths = hweight64(trans->paths_allocated);
s->nr_max_paths = trans->nr_max_paths =
hweight64(trans->paths_allocated);
swap(s->max_paths_text, buf.buf);
}
mutex_unlock(&s->lock);
@ -1419,17 +1420,21 @@ static void bch2_trans_update_max_paths(struct btree_trans *trans)
trans->nr_max_paths = hweight64(trans->paths_allocated);
}
static struct btree_path *btree_path_alloc(struct btree_trans *trans,
struct btree_path *pos)
static noinline void btree_path_overflow(struct btree_trans *trans)
{
bch2_dump_trans_paths_updates(trans);
panic("trans path oveflow\n");
}
static inline struct btree_path *btree_path_alloc(struct btree_trans *trans,
struct btree_path *pos)
{
struct btree_path *path;
unsigned idx;
if (unlikely(trans->paths_allocated ==
~((~0ULL << 1) << (BTREE_ITER_MAX - 1)))) {
bch2_dump_trans_paths_updates(trans);
panic("trans path oveflow\n");
}
~((~0ULL << 1) << (BTREE_ITER_MAX - 1))))
btree_path_overflow(trans);
idx = __ffs64(~trans->paths_allocated);
trans->paths_allocated |= 1ULL << idx;