diff options
Diffstat (limited to 'fs/buffer.c')
| -rw-r--r-- | fs/buffer.c | 43 |
1 files changed, 15 insertions, 28 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index ea0e05ec2916..5715dac7821f 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1281,44 +1281,31 @@ static inline void check_irqs_on(void) } /* - * The LRU management algorithm is dopey-but-simple. Sorry. + * Install a buffer_head into this cpu's LRU. If not already in the LRU, it is + * inserted at the front, and the buffer_head at the back if any is evicted. + * Or, if already in the LRU it is moved to the front. */ static void bh_lru_install(struct buffer_head *bh) { - struct buffer_head *evictee = NULL; + struct buffer_head *evictee = bh; + struct bh_lru *b; + int i; check_irqs_on(); bh_lru_lock(); - if (__this_cpu_read(bh_lrus.bhs[0]) != bh) { - struct buffer_head *bhs[BH_LRU_SIZE]; - int in; - int out = 0; - - get_bh(bh); - bhs[out++] = bh; - for (in = 0; in < BH_LRU_SIZE; in++) { - struct buffer_head *bh2 = - __this_cpu_read(bh_lrus.bhs[in]); - if (bh2 == bh) { - __brelse(bh2); - } else { - if (out >= BH_LRU_SIZE) { - BUG_ON(evictee != NULL); - evictee = bh2; - } else { - bhs[out++] = bh2; - } - } + b = this_cpu_ptr(&bh_lrus); + for (i = 0; i < BH_LRU_SIZE; i++) { + swap(evictee, b->bhs[i]); + if (evictee == bh) { + bh_lru_unlock(); + return; } - while (out < BH_LRU_SIZE) - bhs[out++] = NULL; - memcpy(this_cpu_ptr(&bh_lrus.bhs), bhs, sizeof(bhs)); } - bh_lru_unlock(); - if (evictee) - __brelse(evictee); + get_bh(bh); + bh_lru_unlock(); + brelse(evictee); } /* |