diff options
| -rw-r--r-- | fs/gfs2/glock.c | 126 |
1 files changed, 104 insertions, 22 deletions
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index 1029340..11d48b96 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -15,6 +15,7 @@ #include <linux/buffer_head.h> #include <linux/delay.h> #include <linux/sort.h> +#include <linux/hash.h> #include <linux/jhash.h> #include <linux/kallsyms.h> #include <linux/gfs2_ondisk.h> @@ -80,6 +81,66 @@ static struct rhashtable_params ht_parms = { static struct rhashtable gl_hash_table; +#define GLOCK_WAIT_TABLE_BITS 12 +#define GLOCK_WAIT_TABLE_SIZE (1 << GLOCK_WAIT_TABLE_BITS) +static wait_queue_head_t glock_wait_table[GLOCK_WAIT_TABLE_SIZE] __cacheline_aligned; + +struct wait_glock_queue { + struct lm_lockname *name; + wait_queue_entry_t wait; +}; + +static int glock_wake_function(wait_queue_entry_t *wait, unsigned int mode, + int sync, void *key) +{ + struct wait_glock_queue *wait_glock = + container_of(wait, struct wait_glock_queue, wait); + struct lm_lockname *wait_name = wait_glock->name; + struct lm_lockname *wake_name = key; + + if (wake_name->ln_sbd != wait_name->ln_sbd || + wake_name->ln_number != wait_name->ln_number || + wake_name->ln_type != wait_name->ln_type) + return 0; + return autoremove_wake_function(wait, mode, sync, key); +} + +static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name) +{ + u32 hash = jhash2((u32 *)name, sizeof(*name) / 4, 0); + + return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS); +} + +static void prepare_to_wait_on_glock(wait_queue_head_t **wq, + struct wait_glock_queue *wait, + struct lm_lockname *name) +{ + wait->name = name; + init_wait(&wait->wait); + wait->wait.func = glock_wake_function; + *wq = glock_waitqueue(name); + prepare_to_wait(*wq, &wait->wait, TASK_UNINTERRUPTIBLE); +} + +static void finish_wait_on_glock(wait_queue_head_t *wq, + struct wait_glock_queue *wait) +{ + finish_wait(wq, &wait->wait); +} + +/** + * wake_up_glock - Wake up waiters on a glock + * @gl: the glock + */ +static void wake_up_glock(struct gfs2_glock *gl) +{ + wait_queue_head_t *wq = glock_waitqueue(&gl->gl_name); + + if (waitqueue_active(wq)) + __wake_up(wq, TASK_NORMAL, 1, &gl->gl_name); +} + static void gfs2_glock_dealloc(struct rcu_head *rcu) { struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu); @@ -96,6 +157,9 @@ void gfs2_glock_free(struct gfs2_glock *gl) { struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; + rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms); + smp_mb(); + wake_up_glock(gl); call_rcu(&gl->gl_rcu, gfs2_glock_dealloc); if (atomic_dec_and_test(&sdp->sd_glock_disposal)) wake_up(&sdp->sd_glock_wait); @@ -194,7 +258,6 @@ static void __gfs2_glock_put(struct gfs2_glock *gl) gfs2_glock_remove_from_lru(gl); spin_unlock(&gl->gl_lockref.lock); - rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms); GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders)); GLOCK_BUG_ON(gl, mapping && mapping->nrpages); trace_gfs2_glock_put(gl); @@ -679,6 +742,36 @@ static void glock_work_func(struct work_struct *work) spin_unlock(&gl->gl_lockref.lock); } +static struct gfs2_glock *find_insert_glock(struct lm_lockname *name, + struct gfs2_glock *new) +{ + struct wait_glock_queue wait; + wait_queue_head_t *wq; + struct gfs2_glock *gl; + +again: + prepare_to_wait_on_glock(&wq, &wait, name); + rcu_read_lock(); + if (new) { + gl = rhashtable_lookup_get_insert_fast(&gl_hash_table, + &new->gl_node, ht_parms); + if (IS_ERR(gl)) + goto out; + } else { + gl = rhashtable_lookup_fast(&gl_hash_table, + name, ht_parms); + } + if (gl && !lockref_get_not_dead(&gl->gl_lockref)) { + rcu_read_unlock(); + schedule(); + goto again; + } +out: + rcu_read_unlock(); + finish_wait_on_glock(wq, &wait); + return gl; +} + /** * gfs2_glock_get() - Get a glock, or create one if one doesn't exist * @sdp: The GFS2 superblock @@ -705,15 +798,11 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, struct kmem_cache *cachep; int ret = 0; - rcu_read_lock(); - gl = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms); - if (gl && !lockref_get_not_dead(&gl->gl_lockref)) - gl = NULL; - rcu_read_unlock(); - - *glp = gl; - if (gl) + gl = find_insert_glock(&name, NULL); + if (gl) { + *glp = gl; return 0; + } if (!create) return -ENOENT; @@ -767,10 +856,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number, mapping->writeback_index = 0; } -again: - rcu_read_lock(); - tmp = rhashtable_lookup_get_insert_fast(&gl_hash_table, &gl->gl_node, - ht_parms); + tmp = find_insert_glock(&name, gl); if (!tmp) { *glp = gl; goto out; @@ -779,13 +865,7 @@ again: ret = PTR_ERR(tmp); goto out_free; } - if (lockref_get_not_dead(&tmp->gl_lockref)) { - *glp = tmp; - goto out_free; - } - rcu_read_unlock(); - cond_resched(); - goto again; + *glp = tmp; out_free: kfree(gl->gl_lksb.sb_lvbptr); @@ -793,7 +873,6 @@ out_free: atomic_dec(&sdp->sd_glock_disposal); out: - rcu_read_unlock(); return ret; } @@ -1806,7 +1885,7 @@ static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr) int __init gfs2_glock_init(void) { - int ret; + int i, ret; ret = rhashtable_init(&gl_hash_table, &ht_parms); if (ret < 0) @@ -1835,6 +1914,9 @@ int __init gfs2_glock_init(void) return ret; } + for (i = 0; i < GLOCK_WAIT_TABLE_SIZE; i++) + init_waitqueue_head(glock_wait_table + i); + return 0; } |
