fput() and delayed_fput() can use llist and avoid the locking. This is unlikely path, it is not that this change can improve the performance, but this way the code looks simpler.
Suggested-by: Andrew Morton <[email protected]> Signed-off-by: Oleg Nesterov <[email protected]> --- fs/file_table.c | 25 ++++++++++--------------- include/linux/fs.h | 2 ++ 2 files changed, 12 insertions(+), 15 deletions(-) diff --git a/fs/file_table.c b/fs/file_table.c index 3a2bbc5..94b1bfa 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -265,18 +265,15 @@ static void __fput(struct file *file) mntput(mnt); } -static DEFINE_SPINLOCK(delayed_fput_lock); -static LIST_HEAD(delayed_fput_list); +static LLIST_HEAD(delayed_fput_list); static void delayed_fput(struct work_struct *unused) { - LIST_HEAD(head); - spin_lock_irq(&delayed_fput_lock); - list_splice_init(&delayed_fput_list, &head); - spin_unlock_irq(&delayed_fput_lock); - while (!list_empty(&head)) { - struct file *f = list_first_entry(&head, struct file, f_u.fu_list); - list_del_init(&f->f_u.fu_list); - __fput(f); + struct llist_node *node = llist_del_all(&delayed_fput_list); + struct llist_node *next; + + for (; node; node = next) { + next = llist_next(node); + __fput(llist_entry(node, struct file, f_u.fu_llist)); } } @@ -306,7 +303,6 @@ void fput(struct file *file) { if (atomic_long_dec_and_test(&file->f_count)) { struct task_struct *task = current; - unsigned long flags; file_sb_list_del(file); if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) { @@ -320,10 +316,9 @@ void fput(struct file *file) * fput to avoid leaking *file. */ } - spin_lock_irqsave(&delayed_fput_lock, flags); - list_add(&file->f_u.fu_list, &delayed_fput_list); - schedule_work(&delayed_fput_work); - spin_unlock_irqrestore(&delayed_fput_lock, flags); + + if (llist_add(&file->f_u.fu_llist, &delayed_fput_list)) + schedule_work(&delayed_fput_work); } } diff --git a/include/linux/fs.h b/include/linux/fs.h index 43db02e..8a60d99 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -10,6 +10,7 @@ #include <linux/stat.h> #include <linux/cache.h> #include <linux/list.h> +#include <linux/llist.h> #include <linux/radix-tree.h> #include <linux/rbtree.h> #include <linux/init.h> @@ -767,6 +768,7 @@ struct file { */ union { struct list_head fu_list; + struct llist_node fu_llist; struct rcu_head fu_rcuhead; } f_u; struct path f_path; -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
