projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | #ifndef _LINUX_BLOCKGROUP_LOCK_H |
| 2 | #define _LINUX_BLOCKGROUP_LOCK_H | |
| 3 | /* | |
| 4 | * Per-blockgroup locking for ext2 and ext3. | |
| 5 | * | |
| 6 | * Simple hashed spinlocking. | |
| 7 | */ | |
| 8 | ||
| 9 | #include <linux/config.h> | |
| 10 | #include <linux/spinlock.h> | |
| 11 | #include <linux/cache.h> | |
| 12 | ||
| 13 | #ifdef CONFIG_SMP | |
| 14 | ||
| 15 | /* | |
| 16 | * We want a power-of-two. Is there a better way than this? | |
| 17 | */ | |
| 18 | ||
| 19 | #if NR_CPUS >= 32 | |
| 20 | #define NR_BG_LOCKS 128 | |
| 21 | #elif NR_CPUS >= 16 | |
| 22 | #define NR_BG_LOCKS 64 | |
| 23 | #elif NR_CPUS >= 8 | |
| 24 | #define NR_BG_LOCKS 32 | |
| 25 | #elif NR_CPUS >= 4 | |
| 26 | #define NR_BG_LOCKS 16 | |
| 27 | #elif NR_CPUS >= 2 | |
| 28 | #define NR_BG_LOCKS 8 | |
| 29 | #else | |
| 30 | #define NR_BG_LOCKS 4 | |
| 31 | #endif | |
| 32 | ||
| 33 | #else /* CONFIG_SMP */ | |
| 34 | #define NR_BG_LOCKS 1 | |
| 35 | #endif /* CONFIG_SMP */ | |
| 36 | ||
| 37 | struct bgl_lock { | |
| 38 | spinlock_t lock; | |
| 39 | } ____cacheline_aligned_in_smp; | |
| 40 | ||
| 41 | struct blockgroup_lock { | |
| 42 | struct bgl_lock locks[NR_BG_LOCKS]; | |
| 43 | }; | |
| 44 | ||
| 45 | static inline void bgl_lock_init(struct blockgroup_lock *bgl) | |
| 46 | { | |
| 47 | int i; | |
| 48 | ||
| 49 | for (i = 0; i < NR_BG_LOCKS; i++) | |
| 50 | spin_lock_init(&bgl->locks[i].lock); | |
| 51 | } | |
| 52 | ||
| 53 | /* | |
| 54 | * The accessor is a macro so we can embed a blockgroup_lock into different | |
| 55 | * superblock types | |
| 56 | */ | |
| 57 | #define sb_bgl_lock(sb, block_group) \ | |
| 58 | (&(sb)->s_blockgroup_lock.locks[(block_group) & (NR_BG_LOCKS-1)].lock) | |
| 59 | ||
| 60 | #endif |