diff options
Diffstat (limited to 'fs/locks.c')
| -rw-r--r-- | fs/locks.c | 69 |
1 files changed, 49 insertions, 20 deletions
diff --git a/fs/locks.c b/fs/locks.c index c98e1a1431ea..b27a3005d78d 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -127,6 +127,8 @@ #include <linux/rcupdate.h> #include <linux/pid_namespace.h> #include <linux/hashtable.h> +#include <linux/percpu.h> +#include <linux/lglock.h> #include <asm/uaccess.h> @@ -155,11 +157,13 @@ int lease_break_time = 45; for (lockp = &inode->i_flock; *lockp != NULL; lockp = &(*lockp)->fl_next) /* - * The global file_lock_list is only used for displaying /proc/locks. Protected - * by the file_lock_lock. + * The global file_lock_list is only used for displaying /proc/locks, so we + * keep a list on each CPU, with each list protected by its own spinlock via + * the file_lock_lglock. Note that alterations to the list also require that + * the relevant i_lock is held. */ -static HLIST_HEAD(file_lock_list); -static DEFINE_SPINLOCK(file_lock_lock); +DEFINE_STATIC_LGLOCK(file_lock_lglock); +static DEFINE_PER_CPU(struct hlist_head, file_lock_list); /* * The blocked_hash is used to find POSIX lock loops for deadlock detection. @@ -506,20 +510,30 @@ static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) return fl1->fl_owner == fl2->fl_owner; } +/* Must be called with the i_lock held! */ static inline void locks_insert_global_locks(struct file_lock *fl) { - spin_lock(&file_lock_lock); - hlist_add_head(&fl->fl_link, &file_lock_list); - spin_unlock(&file_lock_lock); + lg_local_lock(&file_lock_lglock); + fl->fl_link_cpu = smp_processor_id(); + hlist_add_head(&fl->fl_link, this_cpu_ptr(&file_lock_list)); + lg_local_unlock(&file_lock_lglock); } +/* Must be called with the i_lock held! */ static inline void locks_delete_global_locks(struct file_lock *fl) { - spin_lock(&file_lock_lock); + /* + * Avoid taking lock if already unhashed. This is safe since this check + * is done while holding the i_lock, and new insertions into the list + * also require that it be held. + */ + if (hlist_unhashed(&fl->fl_link)) + return; + lg_local_lock_cpu(&file_lock_lglock, fl->fl_link_cpu); hlist_del_init(&fl->fl_link); - spin_unlock(&file_lock_lock); + lg_local_unlock_cpu(&file_lock_lglock, fl->fl_link_cpu); } static unsigned long @@ -2243,6 +2257,11 @@ EXPORT_SYMBOL_GPL(vfs_cancel_lock); #include <linux/proc_fs.h> #include <linux/seq_file.h> +struct locks_iterator { + int li_cpu; + loff_t li_pos; +}; + static void lock_get_status(struct seq_file *f, struct file_lock *fl, loff_t id, char *pfx) { @@ -2316,39 +2335,41 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl, static int locks_show(struct seq_file *f, void *v) { + struct locks_iterator *iter = f->private; struct file_lock *fl, *bfl; fl = hlist_entry(v, struct file_lock, fl_link); - lock_get_status(f, fl, *((loff_t *)f->private), ""); + lock_get_status(f, fl, iter->li_pos, ""); list_for_each_entry(bfl, &fl->fl_block, fl_block) - lock_get_status(f, bfl, *((loff_t *)f->private), " ->"); + lock_get_status(f, bfl, iter->li_pos, " ->"); return 0; } static void *locks_start(struct seq_file *f, loff_t *pos) { - loff_t *p = f->private; + struct locks_iterator *iter = f->private; - spin_lock(&file_lock_lock); + iter->li_pos = *pos + 1; + lg_global_lock(&file_lock_lglock); spin_lock(&blocked_lock_lock); - *p = (*pos + 1); - return seq_hlist_start(&file_lock_list, *pos); + return seq_hlist_start_percpu(&file_lock_list, &iter->li_cpu, *pos); } static void *locks_next(struct seq_file *f, void *v, loff_t *pos) { - loff_t *p = f->private; - ++*p; - return seq_hlist_next(v, &file_lock_list, pos); + struct locks_iterator *iter = f->private; + + ++iter->li_pos; + return seq_hlist_next_percpu(v, &file_lock_list, &iter->li_cpu, pos); } static void locks_stop(struct seq_file *f, void *v) { spin_unlock(&blocked_lock_lock); - spin_unlock(&file_lock_lock); + lg_global_unlock(&file_lock_lglock); } static const struct seq_operations locks_seq_operations = { @@ -2360,7 +2381,8 @@ static const struct seq_operations locks_seq_operations = { static int locks_open(struct inode *inode, struct file *filp) { - return seq_open_private(filp, &locks_seq_operations, sizeof(loff_t)); + return seq_open_private(filp, &locks_seq_operations, + sizeof(struct locks_iterator)); } static const struct file_operations proc_locks_operations = { @@ -2460,9 +2482,16 @@ EXPORT_SYMBOL(lock_may_write); static int __init filelock_init(void) { + int i; + filelock_cache = kmem_cache_create("file_lock_cache", sizeof(struct file_lock), 0, SLAB_PANIC, NULL); + lg_lock_init(&file_lock_lglock, "file_lock_lglock"); + + for_each_possible_cpu(i) + INIT_HLIST_HEAD(per_cpu_ptr(&file_lock_list, i)); + return 0; } |