We don't require a dedicated thread for fsnotify cleanup. Switch it over
to a workqueue job instead that runs on the system_unbound_wq.
In the interest of not thrashing the queued job too often when there are
a lot of marks being removed, we delay the reaper job slightly when
queueing it, to allow several to gather on the list.
Cc: Jan Kara <jack@xxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Eryu Guan <guaneryu@xxxxxxxxx>
Signed-off-by: Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx>
---
fs/notify/mark.c | 49 ++++++++++++++++++-------------------------------
1 file changed, 18 insertions(+), 31 deletions(-)
diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index fc0df4442f7b..7115c5d7d373 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -91,10 +91,14 @@
#include <linux/fsnotify_backend.h>
#include "fsnotify.h"
+#define FSNOTIFY_REAPER_DELAY (1) /* 1 jiffy */
+
struct srcu_struct fsnotify_mark_srcu;
static DEFINE_SPINLOCK(destroy_lock);
static LIST_HEAD(destroy_list);
-static DECLARE_WAIT_QUEUE_HEAD(destroy_waitq);
+
+static void fsnotify_mark_destroy(struct work_struct *work);
+static DECLARE_DELAYED_WORK(reaper_work, fsnotify_mark_destroy);
void fsnotify_get_mark(struct fsnotify_mark *mark)
{
@@ -189,7 +193,8 @@ void fsnotify_free_mark(struct fsnotify_mark *mark)
spin_lock(&destroy_lock);
list_add(&mark->g_list, &destroy_list);
spin_unlock(&destroy_lock);
- wake_up(&destroy_waitq);
+ queue_delayed_work(system_unbound_wq, &reaper_work,
+ FSNOTIFY_REAPER_DELAY);
/*
* Some groups like to know that marks are being freed. This is a
@@ -388,7 +393,8 @@ err:
spin_lock(&destroy_lock);
list_add(&mark->g_list, &destroy_list);
spin_unlock(&destroy_lock);
- wake_up(&destroy_waitq);
+ queue_delayed_work(system_unbound_wq, &reaper_work,
+ FSNOTIFY_REAPER_DELAY);
return ret;
}
@@ -493,39 +499,20 @@ void fsnotify_init_mark(struct fsnotify_mark *mark,
mark->free_mark = free_mark;
}
-static int fsnotify_mark_destroy(void *ignored)
+static void fsnotify_mark_destroy(struct work_struct *work)
{
struct fsnotify_mark *mark, *next;
struct list_head private_destroy_list;
- for (;;) {
- spin_lock(&destroy_lock);
- /* exchange the list head */
- list_replace_init(&destroy_list, &private_destroy_list);
- spin_unlock(&destroy_lock);
-
- synchronize_srcu(&fsnotify_mark_srcu);
+ spin_lock(&destroy_lock);
+ /* exchange the list head */
+ list_replace_init(&destroy_list, &private_destroy_list);
+ spin_unlock(&destroy_lock);
- list_for_each_entry_safe(mark, next, &private_destroy_list, g_list) {
- list_del_init(&mark->g_list);
- fsnotify_put_mark(mark);
- }
+ synchronize_srcu(&fsnotify_mark_srcu);
- wait_event_interruptible(destroy_waitq, !list_empty(&destroy_list));
+ list_for_each_entry_safe(mark, next, &private_destroy_list, g_list) {
+ list_del_init(&mark->g_list);
+ fsnotify_put_mark(mark);
}
-
- return 0;
-}
-
-static int __init fsnotify_mark_init(void)
-{
- struct task_struct *thread;
-
- thread = kthread_run(fsnotify_mark_destroy, NULL,
- "fsnotify_mark");
- if (IS_ERR(thread))
- panic("unable to start fsnotify mark destruction thread.");
-
- return 0;
}
-device_initcall(fsnotify_mark_init);
--
2.5.0
--
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