From: Jeff Layton jlayton@poochiereds.net
commit 0918f1c309b86301605650c836ddd2021d311ae2 upstream.
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.
Signed-off-by: Jeff Layton jeff.layton@primarydata.com Tested-by: Eryu Guan guaneryu@gmail.com Reviewed-by: Jan Kara jack@suse.cz Cc: Eric Paris eparis@parisplace.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org [mruffell: cherry picked] Signed-off-by: Matthew Ruffell matthew.ruffell@canonical.com --- 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);