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fsnotify: turn fsnotify reaper thread into a workqueue job 

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>
This commit is contained in:
Jeff Layton 2016-02-17 13:11:21 -08:00 committed by Linus Torvalds
parent 13d34ac6e5
commit 0918f1c309
1 changed files with 18 additions and 31 deletions
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49
fs/notify/mark.c
View File

@ -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 @@ int fsnotify_add_mark_locked(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);
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);
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);
synchronize_srcu(&fsnotify_mark_srcu);
list_for_each_entry_safe(mark, next, &private_destroy_list, g_list) {
list_del_init(&mark->g_list);
fsnotify_put_mark(mark);
}
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);