diff options
| author | David Sterba <dsterba@suse.com> | 2023-09-08 01:09:42 +0200 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2023-10-12 16:44:05 +0200 |
| commit | 150cce2d9fbe0acb48da737f8ea443d8b0847b72 (patch) | |
| tree | fbef46f40dd8c8fff3a87c35f1ca1b513114f837 /fs/btrfs/locking.c | |
| parent | 321f4992c127458e51009b5160567b72e3442ff3 (diff) | |
btrfs: move extent_buffer::lock_owner to debug section
The lock_owner is used for a rare corruption case and we haven't seen
any reports in years. Move it to the debugging section of eb. To close
the holes also move log_index so the final layout looks like:
struct extent_buffer {
u64 start; /* 0 8 */
long unsigned int len; /* 8 8 */
long unsigned int bflags; /* 16 8 */
struct btrfs_fs_info * fs_info; /* 24 8 */
spinlock_t refs_lock; /* 32 4 */
atomic_t refs; /* 36 4 */
int read_mirror; /* 40 4 */
s8 log_index; /* 44 1 */
/* XXX 3 bytes hole, try to pack */
struct callback_head callback_head __attribute__((__aligned__(8))); /* 48 16 */
/* --- cacheline 1 boundary (64 bytes) --- */
struct rw_semaphore lock; /* 64 40 */
struct page * pages[16]; /* 104 128 */
/* size: 232, cachelines: 4, members: 11 */
/* sum members: 229, holes: 1, sum holes: 3 */
/* forced alignments: 1, forced holes: 1, sum forced holes: 3 */
/* last cacheline: 40 bytes */
} __attribute__((__aligned__(8)));
This saves 8 bytes in total and still keeps the lock on a separate cacheline.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/locking.c')
| -rw-r--r-- | fs/btrfs/locking.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c index c3128cdf1177..6ac4fd8cc8dc 100644 --- a/fs/btrfs/locking.c +++ b/fs/btrfs/locking.c @@ -103,6 +103,15 @@ void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root, struct extent_buff #endif +#ifdef CONFIG_BTRFS_DEBUG +static void btrfs_set_eb_lock_owner(struct extent_buffer *eb, pid_t owner) +{ + eb->lock_owner = owner; +} +#else +static void btrfs_set_eb_lock_owner(struct extent_buffer *eb, pid_t owner) { } +#endif + /* * Extent buffer locking * ===================== @@ -165,7 +174,7 @@ int btrfs_try_tree_read_lock(struct extent_buffer *eb) int btrfs_try_tree_write_lock(struct extent_buffer *eb) { if (down_write_trylock(&eb->lock)) { - eb->lock_owner = current->pid; + btrfs_set_eb_lock_owner(eb, current->pid); trace_btrfs_try_tree_write_lock(eb); return 1; } @@ -198,7 +207,7 @@ void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest) start_ns = ktime_get_ns(); down_write_nested(&eb->lock, nest); - eb->lock_owner = current->pid; + btrfs_set_eb_lock_owner(eb, current->pid); trace_btrfs_tree_lock(eb, start_ns); } @@ -213,7 +222,7 @@ void btrfs_tree_lock(struct extent_buffer *eb) void btrfs_tree_unlock(struct extent_buffer *eb) { trace_btrfs_tree_unlock(eb); - eb->lock_owner = 0; + btrfs_set_eb_lock_owner(eb, 0); up_write(&eb->lock); } |