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authorOleg Nesterov <oleg@redhat.com>2013-07-08 14:24:16 -0700
committerAl Viro <viro@zeniv.linux.org.uk>2013-07-13 13:29:10 +0400
commit4f5e65a1cc90bbb15b9f6cdc362922af1bcc155a (patch)
treec635e87d98c9961ad95c2351bae6d9609eeb761f
parent64372501e2af9b11e2ffd1ff79345dc4b1abe539 (diff)
downloadlinux-4f5e65a1cc90bbb15b9f6cdc362922af1bcc155a.tar.gz
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>
-rw-r--r--fs/file_table.c25
-rw-r--r--include/linux/fs.h2
2 files changed, 12 insertions, 15 deletions
diff --git a/fs/file_table.c b/fs/file_table.c
index b9a77ad08b4..b44e4c55978 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 834c9e5113d..d40e8e78bbd 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>
@@ -768,6 +769,7 @@ struct file {
*/
union {
struct list_head fu_list;
+ struct llist_node fu_llist;
struct rcu_head fu_rcuhead;
} f_u;
struct path f_path;