kevin/linux
1
Fork 0
Code

bcachefs: Kill nodes_intent_locked

Browse Source 
Previously, we used two different bit arrays for tracking held btree
node locks. This patch switches to an array of two bit integers, which
will let us track, in a future patch, when we hold a write lock.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
This commit is contained in:
Kent Overstreet 2022-08-21 17:20:42 -04:00 committed by Kent Overstreet
parent d4263e5638
commit 2e27f6567b
3 changed files with 9 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/bcachefs/btree_iter.c
View File

@ -1519,7 +1519,6 @@ static struct btree_path *btree_path_alloc(struct btree_trans *trans,
path->ref = 0;
path->intent_ref = 0;
path->nodes_locked = 0;
path->nodes_intent_locked = 0;
btree_path_list_add(trans, pos, path);
trans->paths_sorted = false;
@ -1574,7 +1573,6 @@ struct btree_path *bch2_path_get(struct btree_trans *trans,
path->level = level;
path->locks_want = locks_want;
path->nodes_locked = 0;
path->nodes_intent_locked = 0;
for (i = 0; i < ARRAY_SIZE(path->l); i++)
path->l[i].b = ERR_PTR(-BCH_ERR_no_btree_node_init);
#ifdef CONFIG_BCACHEFS_DEBUG

26
fs/bcachefs/btree_locking.h
View File

@ -37,14 +37,7 @@ enum btree_node_locked_type {
static inline int btree_node_locked_type(struct btree_path *path,
unsigned level)
{
/*
* We're relying on the fact that if nodes_intent_locked is set
* nodes_locked must be set as well, so that we can compute without
* branches:
*/
return BTREE_NODE_UNLOCKED +
((path->nodes_locked >> level) & 1) +
((path->nodes_intent_locked >> level) & 1);
return BTREE_NODE_UNLOCKED + ((path->nodes_locked >> (level << 1)) & 3);
}
static inline bool btree_node_intent_locked(struct btree_path *path,
@ -65,20 +58,15 @@ static inline bool btree_node_locked(struct btree_path *path, unsigned level)
}
static inline void mark_btree_node_locked_noreset(struct btree_path *path,
unsigned level,
enum btree_node_locked_type type)
unsigned level,
enum btree_node_locked_type type)
{
/* relying on this to avoid a branch */
BUILD_BUG_ON(SIX_LOCK_read != 0);
BUILD_BUG_ON(SIX_LOCK_intent != 1);
path->nodes_locked &= ~(1 << level);
path->nodes_intent_locked &= ~(1 << level);
if (type != BTREE_NODE_UNLOCKED) {
path->nodes_locked |= 1 << level;
path->nodes_intent_locked |= type << level;
}
path->nodes_locked &= ~(3U << (level << 1));
path->nodes_locked |= (type + 1) << (level << 1);
}
static inline void mark_btree_node_unlocked(struct btree_path *path,
@ -162,12 +150,12 @@ static inline void btree_node_unlock(struct btree_trans *trans,
static inline int btree_path_lowest_level_locked(struct btree_path *path)
{
return __ffs(path->nodes_locked);
return __ffs(path->nodes_locked) >> 1;
}
static inline int btree_path_highest_level_locked(struct btree_path *path)
{
return __fls(path->nodes_locked);
return __fls(path->nodes_locked) >> 1;
}
static inline void __bch2_btree_path_unlock(struct btree_trans *trans,

5
fs/bcachefs/btree_types.h
View File

@ -232,9 +232,8 @@ struct btree_path {
*/
bool should_be_locked:1;
unsigned level:3,
locks_want:4,
nodes_locked:4,
nodes_intent_locked:4;
locks_want:4;
u8 nodes_locked;
struct btree_path_level {
struct btree *b;