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fput: turn "list_head delayed_fput_list" into llist_head 

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.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Oleg Nesterov 2013-07-08 14:24:16 -07:00 committed by Al Viro
parent 64372501e2
commit 4f5e65a1cc
2 changed files with 12 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
fs/file_table.c
View File

@ -265,18 +265,15 @@ static void __fput(struct file *file)
mntput(mnt); mntput(mnt);
} }
static DEFINE_SPINLOCK(delayed_fput_lock); static LLIST_HEAD(delayed_fput_list);
static LIST_HEAD(delayed_fput_list);
static void delayed_fput(struct work_struct *unused) static void delayed_fput(struct work_struct *unused)
{ {
LIST_HEAD(head); struct llist_node *node = llist_del_all(&delayed_fput_list);
spin_lock_irq(&delayed_fput_lock); struct llist_node *next;
list_splice_init(&delayed_fput_list, &head);
spin_unlock_irq(&delayed_fput_lock); for (; node; node = next) {
while (!list_empty(&head)) { next = llist_next(node);
struct file *f = list_first_entry(&head, struct file, f_u.fu_list); __fput(llist_entry(node, struct file, f_u.fu_llist));
list_del_init(&f->f_u.fu_list);
__fput(f);
} }
} }
@ -306,7 +303,6 @@ void fput(struct file *file)
{ {
if (atomic_long_dec_and_test(&file->f_count)) { if (atomic_long_dec_and_test(&file->f_count)) {
struct task_struct *task = current; struct task_struct *task = current;
unsigned long flags;
file_sb_list_del(file); file_sb_list_del(file);
if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) { if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
@ -320,10 +316,9 @@ void fput(struct file *file)
* fput to avoid leaking *file. * fput to avoid leaking *file.
*/ */
} }
spin_lock_irqsave(&delayed_fput_lock, flags);
list_add(&file->f_u.fu_list, &delayed_fput_list); if (llist_add(&file->f_u.fu_llist, &delayed_fput_list))
schedule_work(&delayed_fput_work); schedule_work(&delayed_fput_work);
spin_unlock_irqrestore(&delayed_fput_lock, flags);
} }
} }

2
include/linux/fs.h
View File

@ -10,6 +10,7 @@
#include <linux/stat.h> #include <linux/stat.h>
#include <linux/cache.h> #include <linux/cache.h>
#include <linux/list.h> #include <linux/list.h>
#include <linux/llist.h>
#include <linux/radix-tree.h> #include <linux/radix-tree.h>
#include <linux/rbtree.h> #include <linux/rbtree.h>
#include <linux/init.h> #include <linux/init.h>
@ -768,6 +769,7 @@ struct file {
*/ */
union { union {
struct list_head fu_list; struct list_head fu_list;
struct llist_node fu_llist;
struct rcu_head fu_rcuhead; struct rcu_head fu_rcuhead;
} f_u; } f_u;
struct path f_path; struct path f_path;