diff options
| -rw-r--r-- | include/linux/cgroup-defs.h | 2 | ||||
| -rw-r--r-- | kernel/cgroup/cgroup.c | 25 |
2 files changed, 25 insertions, 2 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index dc5b70449dc6..133531fcfb33 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -105,6 +105,8 @@ enum { struct cgroup_file { /* do not access any fields from outside cgroup core */ struct kernfs_node *kn; + unsigned long notified_at; + struct timer_list notify_timer; }; /* diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 25309c868728..fdb7a582f8fc 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -61,6 +61,8 @@ #define CGROUP_FILE_NAME_MAX (MAX_CGROUP_TYPE_NAMELEN + \ MAX_CFTYPE_NAME + 2) +/* let's not notify more than 100 times per second */ +#define CGROUP_FILE_NOTIFY_MIN_INTV DIV_ROUND_UP(HZ, 100) /* * cgroup_mutex is the master lock. Any modification to cgroup or its @@ -1554,6 +1556,8 @@ static void cgroup_rm_file(struct cgroup *cgrp, const struct cftype *cft) spin_lock_irq(&cgroup_file_kn_lock); cfile->kn = NULL; spin_unlock_irq(&cgroup_file_kn_lock); + + del_timer_sync(&cfile->notify_timer); } kernfs_remove_by_name(cgrp->kn, cgroup_file_name(cgrp, cft, name)); @@ -3532,6 +3536,12 @@ static int cgroup_kn_set_ugid(struct kernfs_node *kn) return kernfs_setattr(kn, &iattr); } +static void cgroup_file_notify_timer(struct timer_list *timer) +{ + cgroup_file_notify(container_of(timer, struct cgroup_file, + notify_timer)); +} + static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp, struct cftype *cft) { @@ -3558,6 +3568,8 @@ static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp, if (cft->file_offset) { struct cgroup_file *cfile = (void *)css + cft->file_offset; + timer_setup(&cfile->notify_timer, cgroup_file_notify_timer, 0); + spin_lock_irq(&cgroup_file_kn_lock); cfile->kn = kn; spin_unlock_irq(&cgroup_file_kn_lock); @@ -3807,8 +3819,17 @@ void cgroup_file_notify(struct cgroup_file *cfile) unsigned long flags; spin_lock_irqsave(&cgroup_file_kn_lock, flags); - if (cfile->kn) - kernfs_notify(cfile->kn); + if (cfile->kn) { + unsigned long last = cfile->notified_at; + unsigned long next = last + CGROUP_FILE_NOTIFY_MIN_INTV; + + if (time_in_range(jiffies, last, next)) { + timer_reduce(&cfile->notify_timer, next); + } else { + kernfs_notify(cfile->kn); + cfile->notified_at = jiffies; + } + } spin_unlock_irqrestore(&cgroup_file_kn_lock, flags); } |