Messages in this thread |  | | | Date | Tue, 14 Jul 2009 09:47:29 +0900 | | From | KAMEZAWA Hiroyuki <> | | Subject | Re: [PATCH 1/2] Resource usage threshold notification addition to res_counter (v3) |
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On Mon, 13 Jul 2009 17:36:40 -0700 Paul Menage <menage@google.com> wrote:
> As I mentioned in another thread, I think that associating the > threshold with the res_counter rather than with each individual waiter > is a mistake, since it creates global state and makes it hard to have > multiple waiters on the same cgroup. > Ah, Hmm...maybe yes.
But the problem is "hierarchy". (even if this usage notifier don't handle it.)
While we charge as following res_coutner+hierarchy
res_counter_A + PAGE_SIZE res_counter_B + PAGE_SIZE res_counter_C + PAGE_SIZE
Checking "where we exceeds" in smart way is not very easy. Balbir's soft limit does similar check but it's not very smart, either I think.
If there are prural thesholds (notifer, softlimit, etc...), this is worth to be tried. Hmm...if not, size of res_coutner excees 128bytes and we'll see terrible counter. Any idea ?
Thanks, -Kame
> Paul > > On Mon, Jul 13, 2009 at 5:16 PM, Vladislav > Buzov<vbuzov@embeddedalley.com> wrote: > > This patch updates the Resource Counter to add a configurable resource usage > > threshold notification mechanism. > > > > Signed-off-by: Vladislav Buzov <vbuzov@embeddedalley.com> > > Signed-off-by: Dan Malek <dan@embeddedalley.com> > > --- > > Documentation/cgroups/resource_counter.txt | 21 ++++++++- > > include/linux/res_counter.h | 69 ++++++++++++++++++++++++++++ > > kernel/res_counter.c | 7 +++ > > 3 files changed, 95 insertions(+), 2 deletions(-) > > > > diff --git a/Documentation/cgroups/resource_counter.txt b/Documentation/cgroups/resource_counter.txt > > index 95b24d7..1369dff 100644 > > --- a/Documentation/cgroups/resource_counter.txt > > +++ b/Documentation/cgroups/resource_counter.txt > > @@ -39,7 +39,20 @@ to work with it. > > The failcnt stands for "failures counter". This is the number of > > resource allocation attempts that failed. > > > > - c. spinlock_t lock > > + e. unsigned long long threshold > > + > > + The resource usage threshold to notify the resouce controller. This is > > + the minimal difference between the resource limit and current usage > > + to fire a notification. > > + > > + f. void (*threshold_notifier)(struct res_counter *counter) > > + > > + The threshold notification callback installed by the resource > > + controller. Called when the usage reaches or exceeds the threshold. > > + Should be fast and not sleep because called when interrupts are > > + disabled. > > + > > + g. spinlock_t lock > > > > Protects changes of the above values. > > > > @@ -140,6 +153,7 @@ counter fields. They are recommended to adhere to the following rules: > > usage usage_in_<unit_of_measurement> > > max_usage max_usage_in_<unit_of_measurement> > > limit limit_in_<unit_of_measurement> > > + threshold notify_threshold_in_<unit_of_measurement> > > failcnt failcnt > > lock no file :) > > > > @@ -153,9 +167,12 @@ counter fields. They are recommended to adhere to the following rules: > > usage prohibited > > max_usage reset to usage > > limit set the limit > > + threshold set the threshold > > failcnt reset to zero > > > > - > > + d. Notification is enabled by installing the threshold notifier callback. It > > + is up to the resouce controller to communicate the notification to user > > + space tasks. > > > > 5. Usage example > > > > diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h > > index 511f42f..5ec98d7 100644 > > --- a/include/linux/res_counter.h > > +++ b/include/linux/res_counter.h > > @@ -9,6 +9,11 @@ > > * > > * Author: Pavel Emelianov <xemul@openvz.org> > > * > > + * Resouce usage threshold notification update > > + * Copyright 2009 CE Linux Forum and Embedded Alley Solutions, Inc. > > + * Author: Dan Malek <dan@embeddedalley.com> > > + * Author: Vladislav Buzov <vbuzov@embeddedalley.com> > > + * > > * See Documentation/cgroups/resource_counter.txt for more > > * info about what this counter is. > > */ > > @@ -35,6 +40,19 @@ struct res_counter { > > */ > > unsigned long long limit; > > /* > > + * the resource usage threshold to notify the resouce controller. This > > + * is the minimal difference between the resource limit and current > > + * usage to fire a notification. > > + */ > > + unsigned long long threshold; > > + /* > > + * the threshold notification callback installed by the resource > > + * controller. Called when the usage reaches or exceeds the threshold. > > + * Should be fast and not sleep because called when interrupts are > > + * disabled. > > + */ > > + void (*threshold_notifier)(struct res_counter *counter); > > + /* > > * the number of unsuccessful attempts to consume the resource > > */ > > unsigned long long failcnt; > > @@ -87,6 +105,7 @@ enum { > > RES_MAX_USAGE, > > RES_LIMIT, > > RES_FAILCNT, > > + RES_THRESHOLD, > > }; > > > > /* > > @@ -132,6 +151,21 @@ static inline bool res_counter_limit_check_locked(struct res_counter *cnt) > > return false; > > } > > > > +static inline bool res_counter_threshold_check_locked(struct res_counter *cnt) > > +{ > > + if (cnt->usage + cnt->threshold < cnt->limit) > > + return true; > > + > > + return false; > > +} > > + > > +static inline void res_counter_threshold_notify_locked(struct res_counter *cnt) > > +{ > > + if (!res_counter_threshold_check_locked(cnt) && > > + cnt->threshold_notifier) > > + cnt->threshold_notifier(cnt); > > +} > > + > > /* > > * Helper function to detect if the cgroup is within it's limit or > > * not. It's currently called from cgroup_rss_prepare() > > @@ -147,6 +181,21 @@ static inline bool res_counter_check_under_limit(struct res_counter *cnt) > > return ret; > > } > > > > +/* > > + * Helper function to detect if the cgroup usage is under it's threshold or > > + * not. > > + */ > > +static inline bool res_counter_check_under_threshold(struct res_counter *cnt) > > +{ > > + bool ret; > > + unsigned long flags; > > + > > + spin_lock_irqsave(&cnt->lock, flags); > > + ret = res_counter_threshold_check_locked(cnt); > > + spin_unlock_irqrestore(&cnt->lock, flags); > > + return ret; > > +} > > + > > static inline void res_counter_reset_max(struct res_counter *cnt) > > { > > unsigned long flags; > > @@ -174,6 +223,26 @@ static inline int res_counter_set_limit(struct res_counter *cnt, > > spin_lock_irqsave(&cnt->lock, flags); > > if (cnt->usage <= limit) { > > cnt->limit = limit; > > + if (limit <= cnt->threshold) > > + cnt->threshold = 0; > > + else > > + res_counter_threshold_notify_locked(cnt); > > + ret = 0; > > + } > > + spin_unlock_irqrestore(&cnt->lock, flags); > > + return ret; > > +} > > + > > +static inline int res_counter_set_threshold(struct res_counter *cnt, > > + unsigned long long threshold) > > +{ > > + unsigned long flags; > > + int ret = -EINVAL; > > + > > + spin_lock_irqsave(&cnt->lock, flags); > > + if (cnt->limit > threshold) { > > + cnt->threshold = threshold; > > + res_counter_threshold_notify_locked(cnt); > > ret = 0; > > } > > spin_unlock_irqrestore(&cnt->lock, flags); > > diff --git a/kernel/res_counter.c b/kernel/res_counter.c > > index e1338f0..9b36748 100644 > > --- a/kernel/res_counter.c > > +++ b/kernel/res_counter.c > > @@ -5,6 +5,10 @@ > > * > > * Author: Pavel Emelianov <xemul@openvz.org> > > * > > + * Resouce usage threshold notification update > > + * Copyright 2009 CE Linux Forum and Embedded Alley Solutions, Inc. > > + * Author: Dan Malek <dan@embeddedalley.com> > > + * Author: Vladislav Buzov <vbuzov@embeddedalley.com> > > */ > > > > #include <linux/types.h> > > @@ -32,6 +36,7 @@ int res_counter_charge_locked(struct res_counter *counter, unsigned long val) > > counter->usage += val; > > if (counter->usage > counter->max_usage) > > counter->max_usage = counter->usage; > > + res_counter_threshold_notify_locked(counter); > > return 0; > > } > > > > @@ -101,6 +106,8 @@ res_counter_member(struct res_counter *counter, int member) > > return &counter->limit; > > case RES_FAILCNT: > > return &counter->failcnt; > > + case RES_THRESHOLD: > > + return &counter->threshold; > > }; > > > > BUG(); > > -- > > 1.5.6.3 > > > > >
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