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| author | David Sterba <dsterba@suse.com> | 2023-09-08 02:09:42 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2023-10-12 17:44:05 +0300 |
| commit | 150cce2d9fbe0acb48da737f8ea443d8b0847b72 (patch) | |
| tree | fbef46f40dd8c8fff3a87c35f1ca1b513114f837 /fs/btrfs/extent_io.h | |
| parent | 321f4992c127458e51009b5160567b72e3442ff3 (diff) | |
| download | linux-150cce2d9fbe0acb48da737f8ea443d8b0847b72.tar.xz | |
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/extent_io.h')
| -rw-r--r-- | fs/btrfs/extent_io.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index 68368ba99321..2171057a4477 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -80,16 +80,16 @@ struct extent_buffer { spinlock_t refs_lock; atomic_t refs; int read_mirror; - struct rcu_head rcu_head; - pid_t lock_owner; /* >= 0 if eb belongs to a log tree, -1 otherwise */ s8 log_index; + struct rcu_head rcu_head; struct rw_semaphore lock; struct page *pages[INLINE_EXTENT_BUFFER_PAGES]; #ifdef CONFIG_BTRFS_DEBUG struct list_head leak_list; + pid_t lock_owner; #endif }; |